Tesi sul tema "Merino sheep Animal nutrition"

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The objective of this study was to evaluate Dohne Merino sheep and Boer goats in terms of the degradable parameters of a high-fibre diet, a low-fibre diet and two vegetable protein sources commonly used in South Africa. Differences between species were evaluated following the potential differences within species. The feedstuffs used were those for the following diets: low-fibre diet (LF); high-fibre diet (HF); sunflower meal (SFM) oilcake; and soybean meal (SBM) oilcake. In the first trial, the digestible characteristics of the HF and LF diets were determined by means of a digestibility study. A 6 × 6 Latin square design was used to determine whether Dohne Merino sheep or Boer goat wethers differ regarding the digestibility characteristics of low- and high-fibre diets. The diets were fed once daily at 1.24 kg to all the wethers, which had ad libitum access to fresh water. Each period consisted of 10 days of adaptation and seven days of faecal and urinary sampling. The results indicated that the intake and digestibility characteristics of nutrients did not differ between sheep and goats. However, the different diets differed in terms of the nutrient intake and digestibility range of sheep and goats. The second trial was an in sacco degradability trial to determine the dry matter (DM) and crude protein (CP) degradability of the LF, HF, SBM and SFM diets. Six Dohne Merino and six Boer goat wethers were fitted with rumen cannulae so that they could be used in the trial. All wethers received the same basal diet. The samples were incubated in the rumen in polyester Dacron bags, with the bags being removed at intervals of 0h, 3h, 9h, 12h, 24h, 48h, 72h, and 96h for the LF and HF diets. All the oilcake was removed at intervals of 0h, 2h, 4h, 8h, 12h, 16h, 24h, 36h and 48h. The sheep and goats were found not to differ from one another in terms of effective degradability of any of the feedstuffs concerned. However, within species differences were observed. To establish a fully integrated outcome of degradability, the study described in the current thesis was structured in such a way that the in vitro trial ran parallel with the in sacco trial, being performed with the aid of a Daisy Incubator (ANKOM Technology Corp., Fairport, NY). Such a procedure was only adopted in relation to the SFM and SBM diets in order to evaluate their in vitro data in relation to the in sacco data. The same oilcake was tested in the case of both trials, with the composite sample of rumen liquid of four sheep or goats, which was used in the in sacco trial, also being used in the in vitro study. In the study, DM disappearance values were determined and fitted to a single-compartment model by means of an iterative least-square procedure in order to determine the DM and CP degradability parameters. The DM used in vitro or in sacco was compared, using the actual values obtained after 8h incubation, due to only a limited amount of residue being left after incubation. In the study, the in vitro method overestimated the digestibility of SBM by 37% to 39% and the digestibility of SFM by 17% to 20% compared with that found to occur in the in sacco method. In vitro DM disappearance values for all SBM samples were found to be higher than those that were detected in the SFM samples. The percentage of in vitro true digestibility parameters was also calculated. No significant differences were found between species for effective degradability, though differences were observed within species between the two substrates concerned. In conclusion, the sheep and goats used in the study were not found to differ in terms of digestion parameters when they were compared on different types of roughage or protein sources. However, within species differences were, indeed, found to occur. Sheep and goats digested the SBM better than they did the SFM.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om te bepaal of Dohne Merino skape verskil van Boerbokke in terme van degradeerbaarheidsparameters van ‘n hoë vesel-, ‘n lae veseldieët en twee plantaardige proteïenbronne wat algemeen in Suid-Afrika gebruik word. Die verskille tussen spesies is ge-evalueer en daarna die potensiële verskille binne spesies. Die volgende grondstowwe is geëvalueer: ‘n laevesel-dieët (LF), ‘n hoëvesel-dieët (HF), sonneblom-oliekoekmeel (SFM) en sojaboon-oliekoekmeel (SBM). In die eerste proef is die degradeerbaarheidsparameters van die HF dieët en die LF dieët met behulp van ‘n verteerbaarheidstudie bepaal. Dohne Merino hamels of Boerbok kapaters was gebruik om te bepaal of skape en bokke verskil in terme van inname en degradeerbaarheid van voedingstowwe wanneer hul hoë- en lae vesel voere gevoer word. Al die hamels en kapaters het ad libitum toegang tot vars water gehad en hul was een keer per dag (1.24 kg) gevoer. Elke periode het bestaan uit ‘n 10 dag aanpassingsperiode en ‘n toegelate 7 dae vir mis- en urienmonster versameling. Die resultate het aangedui dat die inname- en degradeerbaarheidsparameters van nutriënte beinvloed word deur verskillende diëte binne spesies. Geen verskille is gevind tussen spesies wanneer daar hoë- en lae kwaliteit voere gevoer is nie. Die tweede proef was ‘n in sacco-degradeerbaarheidsstudie om te bepaal wat die droë materiaal (DM) en ruproteïen (RP) verteerbaarheidsparameters van die HF dieët, die LF dieët, die SBM en die SFM is. Ses Dohne Merino’s en ses Boer bokke met rumen kanullas is in die studie gebruik en al die diere het dieselfde basale dieët ontvang. Die monsters is in die rumen geïnkubeer in poliester dakronsakkies en die sakkies is verwyder na onderskeidelik 0 uur, 3 uur, 9 uur, 12 uur, 24 uur, 48 uur, 72 uur en 96 uur intervalle. Laasgenoemde intervalle was geldig vir die lae vesel- en hoëveseldieët. Die oliekoeke se intervalle het verskil en is verwyder na 0 uur, 2 uur, 4 uur, 8 uur, 12 uur, 16 uur, 24 uur, 36 uur en 48 uur. Daar was geen verskille tussen spesies in effektiewe degradeerbaarheid nie, alhoewel verskille voorgekom het binne spesies. Skape verteer veselagtige grondstowwe meer effektief terwyl bokke weer hoë proteïn bevattende grondstowwe beter verteer. Om ‘n volkome geïntegreede uitkoms van degradeerbaarheid te bewerkstellig is die in vitro proef en die in sacco proef gelyktydig gedoen. Die in vitro-degradeerbareheidstudie is met behulp van ‘n ANKOM Daisy Inkubeerder uitgevoer (ANKOM Tegnologie Korp., Fairport, NY) vir net die oliekoek behandelings. Gedurende die studie is dieselfde oliekoeke gebruik. ‘n Saamgestelde monster van die rumenvloeistof van vier van die skape of bokke wat vir die in sacco-studie gebruik was, is gebruik vir die in vitro-inkubasie van die monsters. DM verdwyningparameters is bereken en dan met ‘n interaktiewe kleinste kwadraat prosedure op ‘n een-kompartement model gepas om die in sacco DMdegradeerbaarheidsparameters te bepaal. Die DM verdwyning, na 8h inkubasie, was gebruik om die in vitro en die in sacco metodes met mekaar te vergelyk, weens ‘n beperkte residu na die afloop van die elke inkubasiestudie. Tydens die studie het die in vitro metode degradering oorskat in vergelyking met die in sacco metode. DM verdwyningswaardes vir al die SBM monsters was hoër in vitro as die SFM monsters. In die studie is die persentasie in vitro ware degradeerbaarheidswaardes bereken. Geen verskille is opgemerk tussen spesies vir effektiewe degradeerbaarheid nie. Daar was wel verskille binne spesies. Om af te sluit het dit voorgekom dat skape en bokke nie verskil aan degradeerbaarheidswaardes wanneer daar ‘n vergelyking was tussen verskillende vesels- en proteϊenbronne nie, alhoewel verskille voorgekom het binne spesies. Skape en bokke het SBM effektief beter verteer as SFM.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The aim of this study was to investigate the effect of feedlot production on the growth and carcass characteristics, as well as the distribution of the main tissues (muscle, fat and bone) and meat quality of Merino, South African Mutton Merino (SAMM) and Dorper lambs. The Merino and SAMM 2008 outperformed (P<0.05) the 2007 SAMM and both Dorper production groups in terms of average daily gain, while the Merino and both SAMM production groups achieved the best feed conversion ratio (P<0.05). The highest percentage A2 graded carcasses was achieved after 42 days under feedlot conditions by the Merino and both Dorper production groups, but it took only 21 days in the feedlot for the SAMM lambs to achieve the same result. Slaughter weight, carcass weight and dressing percentage all increased significantly with an increase in the number of days under feedlot conditions for all three breeds, while a decrease in the percentage head, trotters and red offal was also documented. The fatter retail cuts (thick rib, flank, prime rib and loin) increased (P<0.05) in percentage with an increase in the number of days under feedlot conditions. A significant decrease in the percentage leaner retail cuts (raised shoulder and hind-quarters) was found when the amount of days under feedlot conditions increased. The highest profit is obtained by the prime rib, loin and hind-quarters in a lamb carcass. For the Merino and Dorper lambs these three cuts, or a combination of the three showed the highest combined percentages after 42 and 63 days under feedlot conditions, respectively. The late maturing SAMM lambs achieved the highest percentages for these three cuts after 63 and 84 days under feedlot conditions in 2007 and 2008 respectively. Visceral and renal fat deposition increased throughout the production period for all breeds. The Dorper lambs attained the highest subcutaneous fat depth, and also produced the heaviest, but fattest carcasses. For A2-graded carcasses, Dorper lambs had the highest dressing percentage and lowest subcutaneous fat depth, followed by the SAMM and then Merino breed. A decrease in the percentage muscle and bone was found with an increase in the number of days under feedlot conditions, whilst an increase in the percentage fat was found under the same conditions. Meat quality was mostly affected by the 48h post mortem pH. This pH value is affected by the cooling rate of the carcasses, which in turn is affected by the level of carcass fatness. Carcass fatness increased with an increase in the number of days under feedlot conditions, resulting in a low 48h post mortem pH. A low 48h post mortem pH is accompanied by higher percentages of cooking and drip loss, as well as a high a*-colour reading for all three breeds.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van voerkraalproduksie op die groeivermoë, karkaseienskappe, verspreiding van spier, been en vet, en vleiskwaliteit van Merino, Suid-Afrikaanse Vleismerino (SAVM) en Dorperlammers te bepaal. Die Merino en SAVM 2008 produksiegroepe het hoër (P<0.05) gemiddelde daaglikse toenames getoon as die SAVM 2007 en beide Dorper groepe, terwyl die Merino en beide SAVM produksiegroepe die beste voeromset verhoudings bereik het (P<0.05). Die hoogste persentasie A2 gegradeerde karkasse is na 42 dae in die voerkraal deur die Merino en beide Dorper produksiegroepe geproduseer, terwyl dit slegs 21 dae onder dieselfde toestande vir die SAVM groepe geneem het om dieselfde resultaat te lewer. Daar is ‘n betekenisvolle verhoging in slagmassa, karkasmassa en uitslagpersentasie vir al drie die rasse gevind met ‘n toename in die aantal dae in die voerkraal, terwyl ‘n afname in die persentasie kop, pote en haarslag gevind was. Die persentasie vetter groothandelsnitte (dikrib, dunrib, ribtjop en lendesnit) het toegeneem (P<0.05) met ‘n toename in die aantal dae in die voerkraal. ‘n Betekenisvolle afname in die persentasie van die maerder groothandelsnitte (blad en boude) is gevind met ‘n toename in die aantal produksie dae in die voerkraal. Die hoogste inkomste van ‘n lamkarkas is afkomstige van die ribtjop, lende snit en boude. ‘n Kombinasie van hierdie drie snitte was die hoogste vir die lammers van die Merino en beide Dorper groepe na 42 en 63 dae in die voerkraal onderskeidelik. Die laat volwasse SAVM lammers het die hoogste persentasie van hierdie drie snitte bereik na 63 en 84 dae in die voerkraal vir die SAVM 2007 en SAVM 2008 onderskeidelik. Die neerlegging van pensvet en niervet het voortdurend toegeneem deur die produksieperiode vir al drie rasse. Die Dorperlammers het die hoogste onderhuidse vetneerlegging getoon, maar het ook die swaarste en vetste karkasse geproduseer. Dorperlammers het die hoogste uitslagpersentasie en laagste onderhuidse vetneerlegging vir A2 gegradeerde karkasse gehad, gevolg deur die SAVM en Merino. ‘n Afname in die persentasie spier en been in karkasse is waargeneem namate die lammers langer in die voerkraal was, terwyl ‘n toename in die persentasie vet onder dieselfde omstandighede waargeneem is. Die 48h post mortem karkas pH affekteer die meeste vleiskwaliteit eienskappe. Hierdie pH waarde word weer deur die tempo van karkasafkoeling beϊnvloed, wat op sy beurt deur die vetheidsgraad van die karkas bepaal word. Die vetheid van karkasse het toegeneem met ‘n toename in die aantal dae in die voerkraal, wat ‘n lae pH waarde 48h post mortem tot gevolg gehad het. ‘n Lae 48h post mortem pH waarde het gelei tot hoër persentasies kook- en dripverliese en hoë a* kleurlesings vir al drie rasse.

Bibliography : leaves 120-133. Defines the sources of reproductive wastage in FecB FecÊ Booroola Merino x South Australian Merino ewes and examines factors associated with the survival of embryos, fetuses and lambs with the aim of improving net reproduction efficiency. Experiments were conducted to define the problem; to examine factors affecting embryonic and fetal loss; and, to investigate factors influencing wastage at lambing.

Thesis (MScAgric)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: One of the reasons why meat supply does not meet human demand is that man has concentrated on utilising relatively few animal species as a source of meat. Development of unconventional livestock, such as goats, is advocated as a means of increasing global meat production and consumption. Although South Africa possesses large numbers of domestic ruminants, meat consumption has been limited mainly to sheep and cattle. Goats are used to a lesser extent. This is partly attributed to a general belief that goat meat is inferior to mutton and beef. Numerous contradictions regarding comparative goat and sheep growth, carcass characteristics and meat composition exist in literature. Concepts involved with most of the contradictions includes average daHy gain (ADG), dressing percentage, carcass weight distribution and organoleptic characteristics, especially tenderness, juiciness and flavour, particularly as pertaining to animals reared/grown under intensive/feedlot conditions. Therefore this project was undertaken to obtain more information on the growth, carcass and organoleptic characteristics, as well as meat chemical compositions of Boer goat (BG) kids in comparison with South African Mutton merino (MM) lambs, reared under feedlot conditions. Thirty-two BG kids and 32 MM lambs were used for this investigation. All the animals were castrated and weaned before entering the feedlot. Two pelleted diets (fed to 16 animals/species) with either a low (LE; 8.9 MJ/kg OM) or a high (HE, 10.9 MJ/kg OM) metabolisabie energy level were fed individually, ad lib for either 28 or 56 days. Feed and water intake, ADG and feed conversion efficiencies (FCE) were monitored. During the last week of the feeding trial, 12 BG kids and 12 MM lambs were used to evaluate the digestibility of the two diets. After either 28 or 56 days, the animals were slaughtered and the carcasses dissected into South African commercial cuts. The m. semimembranosus and 8-9-10-rib cut of each carcass was dissected for determination of chemical composition, drip loss, cooking loss, shear force values and colour measurement. The m. gracilis was dissected from the hind leg of the carcass and used for sensory evaluation. MM's had significantly higher AOG's than BG's (e.g. MMHE56: 0.281; BGHE56: 0.162 kg/day). Within a diet there was no difference (P>0.05) in FCE between BG's and MM's and only the MM's FCE differed between the LE and HE diet (e.g. BGLE28: 7.65; BGHE28: 6.37; MMLE28: 8.73; MMHE28: 5.56 kg feed/kg weight gain). BGLE digested dry matter (OM), crude protein (CP) and energy more efficiently and had a higher energy retention than MMLE. The two diets had the same ME-value for the goats, which confirms that goats perform equally well on a lower quality feed as their contemporaries on a higher quality feed. Neither species, nor diet affected nitrogen retention. The BG had a 49 % lower (P<0.01) water intake per kg weight gain than the MM on both the high and low energy diets. Both species had a lower (P<0.01) water intake on the high than on the low energy diet. Furthermore, the BG had a daily water intake of only 171 ml/kgo.75 compared to the 302 ml/kgo.75 of the MM. The weight of the liver, empty stomach, head and feet (as a percentage of empty body weight) were higher in goats than in sheep. The MM's had significantly heavier skins, probably due to wool growth. Both kidney fat and gastro-intestinal tract (GIT) fat increased with age. The animals slaughtered after 56 days in the feedlot had significantly longer and deeper carcasses than their contemporaries slaughtered after 28 days. Within a diet and slaughter age, the MM had significantly broader and deeper carcasses than the BG's. BG's had significantly less weight per unit carcass length, and thus more slender carcasses than MM's. Diet had no significant influence on the carcass weight distribution of the goats. However, MM's had heavier carcasses (LE: 19.87 vs. 15.28 kg; HE: 24.01 vs. 17.05 kg) and proportionally heavier ribs and buttocks than BG's. Neither diet nor slaughter age influenced the proximate analysis of the m. semimembranosus, but MM's had significantly lower moisture values than BG's. In the 8-9-10-rib cuts BG's had significantly more moisture and protein and lower fat and energy values than MM's. OM, fat and energy values increased with an increase in slaughter age in both species. BG's had significantly higher concentrations of 11 of the 18 measured essential amino acids in their 8-9- 10-rib cuts than the MM's. Gaat carcasses had higher Ca, K, Mg, Na and P-Ievels than sheep carcasses, regardless of the diet fed. There was a tendency for goat's m. semimembranosus to have a lower Fe-content than that of sheep. BG carcasses had a lower carcass cholesterol content than that of lamb (66.77 vs. 99.28 mg/100g, respectively). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1 n9) acid comprised the greatest proportions of fatty acids in both the m. semimembranosus and 8-9-10-rib cut for both species. On a LE-diet there was no significant difference between the saturated fatty acid (SFA) to unsaturated fatty acid (UFA) ratio of goat meat and lamb. However, on the HEdiet, lamb had a significantly higher SFA:UFA ratio than chevon (m. semimembranosus: 0.842 vs. 0.689; 8-9-10-rib cut: 1.407 vs. 0.892). Organoleptically, a difference was noted between chevon and lamb. Each has a specific species flavour, which was not influenced by energy level of the diet. BG meat was perceived to be stringier than that of the MM, but there was no significant difference in Warner-Bratzler shear force values. Tenderness declined with age in both species and there was also a tendency for goat meat to be less juicy than lamb. Chevon had a more pronounced aftertaste than lamb. No objective differences could be distinguished between the colour of the cooked chevon and lamb. There was a tendency for fresh lamb to have a higher a*-value (redness) than chevon. Although diet did not influence drip loss, drip loss increased with an increase in slaughter age. Only after 56 days did the MM's m. semimembranosus have a significantly higher drip loss than the BG's (LE: 4.84 vs. 3.43%; HE: 4.72 vs. 3.32%). In the m. semimembranosus of both species, cooking loss increased with an increase in slaughter age. Since diet did not influence the growth, carcass weight distribution, water holding capacity, colour, shear force values or organoleptic qualities of chevon, BG's may be finished on a diet with a lower ME-value than that usually formulated for sheep, without a reduction in performance. This may render a direct economic advantage for BG feedlot finishing. Meat from young feedlot goats is not inferior to that of lamb and it has a higher protein percentage and lower fat percentage. Therefore, it can be considered as a healthy food commodity, especially among low-income groups or people wishing to consume a low calorie diet.
AFRIKAANSE OPSOMMING: 'n Vergelykende analise van nutriëntverbruik en vleiskwaliteisparameters van Boerbokke en Suid-Afrikaanse Vleismerino's: Een van die hoofredes waarom die vraag na vleis die aanbod oorskrei, is die feit dat die mens tot op hede net op 'n paar dierspesies as bron van vleis gekonsentreer het. Benutting van niekonvensionele spesies, soos bokke, kan aanbeveel word ten einde die globale vleisproduksie en -verbruik te verhoog. Ten spyte van die feit dat Suid-Afrika oor baie gedomestikeerde herkouerspesies beskik, is vleisverbruik in die verlede tot hoofsaaklik skape en beeste beperk. Bokke is tot 'n mindere mate gebruik. Dit kan gedeeltelik toegeskryf word aan die algemene siening dat bokvleis ondergeskik aan skaap- en beesvleis is. Verskeie teenstrydighede ten opsigte van vergelykings tussen bokke en skape se groei, karkaseienskappe en vleissamestelling bestaan in die literatuur. Teenstrydige resultate ten bpsigte van gemiddelde daaglikse toename (GOT), uitslagpersentasie, karkasgewigverspreiding en organoleptiese eienskappe (veral taaiheid, sappigheid en geur) van diere afgerond onder intensiewe/voerkraal-toestande, kom veral voor. Hierdie projek is vervolgens uitgevoer ten einde meer inligting ten opsigte van die groei, karkas- en organoleptiese eienskappe, sowel as die chemiese samestelling van die vleis van Boerbok (BB) lammers in vergelyking met Suid-Afrikaanse Vleismerino (VM) lammers, onder voerkraal-toestande grootgemaak, te verkry. Twee-en-dertig BB lammers en 32 VM lammers is vir hierdie studie gebruik. AI die diere is gekastreer en gespeen voor hulle in die voerkraal geplaas is. Twee verpilde diëte (gevoer aan 16 diere/spesie) met óf 'n lae (LE, 8.9 MJ/kg DM) óf 'n hoë (HE, 10.9 MJ/kg DM) metaboliseerbare energievlak is individueel, ad lib, vir óf 28 óf 56 dae aan die diere gevoer. Voer- en waterinname, GOT en voeromsettingsdoeltreffendheid (VOD) is gemonitor. Gedurende die laaste week van die voedingsproef is 12 BB'e en 12 VM's gebruik ten einde die verteerbaarheid van die twee diëte te bepaal. Na 28 of 56 dae is die diere geslag en die karkasse in Suid-Afrikaanse kommersiële snitte verdeel. Die m. semimembranosus en 8-9-10-rib snit van elke karkas is verwyder vir bepaling van chemiese samestelling, drupverlies, kookverlies, skeurwaardes en kleurbepaling. Die m. gracilis is uit die agterbeen uitgehaal en vir sensoriese evaluering gebruik. VM's het betekenisvolle hoër GOT's as BB'e (bv. VMHE56: 0.281; BBHE56: 0.162 kg/dag) gehad. Binne 'n dieet was daar geen verskille (P>0.05) in VOD tussen BB'e en VM's nie en net die VM's se VOD het tussen die LE- en HE-dieet verskil (bv. BBLE28: 7.65; BBHE28: 6.37; VMLE28: 8.73; VMHE28: 5.56 kg voer/kg gewigstoename). BBLE het die droë materiaal (DM), ruproteïen (RP) en energie meer effektief verteer en het 'n hoër energieretensie as VMLE gehad. Die twee diëte het dieselfde ME-waarde vir die bokke gehad, wat bevestig dat bokke net so goed op 'n laer kwaliteit voer presteer as op 'n dieet van 'n hoër kwaliteit. Stikstofretensie is nie deur spesie of dieet beïnvloed nie. Die BB het 'n 49% laer (P<0.01) waterinname per kg massatoename op beide die HE- en LE-dieet gehad. Beide spesies het 'n laer (P<0.01) waterinname op die hoë as die lae energie dieet gehad. Verder het die BB ook 'n daaglikse waterinname van slegs 171 ml/kg075 gehad in vergelyking met die 302 ml/kgO.75van die VM. Die gewig van die lewer, leë pens, kop en pote (as persentasie van leë liggaamsgewig) was hoër vir bokke as vir skape. Die VM's se velle was betekenisvol swaarder, waarskynlik as gevolg van wolgroei. Beide niervet en kanaalvet het toegeneem met 'n toename in slagouderdom. Die diere wat na 56 dae in die voerkraal geslag is, het betekensivol langer en dieper karkasse gehad as dié na 28 dae. Binne 'n dieet en slagouderdom, het die skape breër en dieper (P<0.05) karkasse as die bokke gehad. BB'e het betekenisvol minder gewig per eenheid karkaslengte en dus maerder karkasse as VM's gehad. Dieet-energievlak het geen betekenisvolle effek op die verspreiding van karkasgewig by bokke gehad nie. VM's het egter swaarder karkasse (LE: 19.87 vs. 15.28 kg; HE: 24.01 vs. 17.05 kg) en proporsioneel swaarder ribbes en boude as BB'e gehad. Dieet of slagouderdom het nie 'n betekenisvolle effek op die chemiese samestelling (vog, vet, proteïen en as) van die m. semimembransous gehad nie, maar VM's het laer (P<0.05) vogwaardes as BB'e gehad. In die 8-9-10-rib snit het BB'e betekenisvolle hoër vog en proteïen, maar laer vet- en energiewaardes as VM's gehad. In beide spesies het DM, vet en energiewaardes toegeneem met 'n toename in slagouderdom. BG'e het 'n betekenisvolle hoër konsentrasie in 11 van die 18 gemete essensiële aminosure in hul 8-9-10-rib snitte gehad in vergelyking met VM's. Bokkarkasse het ook hoër Ca, K, Mg, N en P-vlakke as skaapkarkasse gehad, ongeag die dieet. Daar was 'n neiging vir die bok m. semimembranosus om 'n laer Fe-inhoud as dié van die skaap te hê. BB-karkasse het 'n laer cholesterol-inhoud as skaapkarkasse (66.77 vs. 99.28 mg/100g, onderskeidelik) gehad. Palmitiensuur (C16:0), steariensuur (C18:0) en oleïensuur (C18:1n9) het die grootste proporsies van die vetsure in beide die m. semimembranosus en 8-9-10-rib snit van beide spesies uitgemaak. Op 'n LE-dieet was daar geen verskil tussen die versadigde (SFA) tot onversadigde (UFA) vetsuur-verhouding van bok- en skaapvleis nie. Op 'n HE-dieet het skaapvleis egter 'n betekenisvol hoër SFA:UFA-verhouding as bokvleis gehad (m. semimembranosus: 0.842 vs. 0.689; 8-9-10-rib snit: 1.40 vs. 0.892, onderskeidelik). Organolepties is 'n verskil tussen bok- en skaapvleis gevind. Elkeen het 'n spesifieke spesiegeur, wat onafhanklik van die dieet was. Bokvleis is waargeneem as meer veselrig as skaapvleis, maar daar was geen verskil in Warner-Bratzler skeurwaardes nie. In beide spesies het sagtheid afgeneem met 'n toename in ouderdom en daar was 'n neiging vir bokvleis om minder sappig as lamsvleis te wees. Bokvleis het ook 'n meer pertinente nasmaak as lam gehad. Geen objektiewe verskil kon tussen die kleur van gekookte skaapen bokvleis onderskei word nie. Daar was egter 'n tendens vir vars lamsvleis om 'n hoër a*- waarde (rooiheid) as bokvleis te hê. Alhoewel dieet nie 'n invloed op drupverlies gehad het nie, het drupverlies toegeneem met 'n toename in slagouderdom. Slegs na 56 dae het die VM se m. semimembranosus 'n hoër (P>0.05) drupverlies as dié van die BB getoon (LE: 4.84 vs. 3.43%; HE: 4.72 vs. 3.32%, onderskeidelik). In die m. semimembranosus van beide spesies het kookverlies toegeneem met 'n toename in slagouderdom. Aangesien dieet nie 'n effek op die groei, karkasgewig-verspreiding, waterhouvermoë, kleur, skeurwaardes of organoleptiese eienskappe van bokvleis gehad het nie, kan BB'e op 'n dieet met 'n laer ME-waarde as wat normaalweg vir skape geformuleer word, afgerond word, sonder om 'n verlaging in produksie te verwag. Dit mag 'n direkte ekonomiese voordeel vir afronding van BB'e in die voerkraal inhou. Vleis van jong voerkraalbokke is nie minderwaardig teenoor die van skape nie e-n dit het 'n hoër proteren- en laer vetpersentasie. Dus kan bokvleis as 'n gesonde voedselbron gesien word, veralonder lae-inkomste groepe of mense wat 'n lae kalorie-dieet wil inneem.

Reproductive neuroendocrine activity and appetite are modulated at the hypothalamus by both nutritional status and photoperiod in the seasonal animal. The objectives of this work were (1) to measure circulating hormones and/or metabolites that relay information about peripheral nutritional status to the hypothalamus, (2) to identify which hypothalamic neuropeptides and receptors that are responsive to photoperiodic and nutritional feedback and (3) to establish which changes in peripheral signals and/or hypothalamic neuropeptides are associated with alterations in the activity of the reproductive neuroendocrine axis. Three main experiments were carried out. The first experiment (Chapter 1) utilised a 2 x 2 design to examine the separate and interactive effects of photoperiod and food restriction on hypothalamic neuropeptide and receptor mRNA expression and on GnRH/LH secretion. In the second experiment (Chapter 2), two components of nutritional status, BC and increased food intake were investigated since both are positively related to reproductive performance in sheep. In the final experiment (Chapter 3) the approach was to use an exogenous treatment to artificially raise plasma insulin in an attempt to "drive" some of the foregoing effects. Collectively these studies have lead to the first localisation AgRp, MCH, orexin, Mc3R, Mc4R gene expression in the ovine hypothalamus. They indicate that circulating insulin and leptin are major factors relaying information about nutritional status to the hypothalamus. In addition, they have dissociated BC and food intake as signals to the hypothalamus. Moreover these studies have provided no evidence that NPY, AgRp, POMC, MCH and ObRb play a role in driving seasonal changes in appetite and gonadotrophin secretion. However they do suggest NPY-ergic and melanocortin pathways are important in maintaining appetite/bodyweight/energy homeostasis or restoring energy balance following perturbation. Furthermore the results show that changes in nutrient-sensitive hypothalamic neuropeptide and receptor gene expression may not necessarily lead to alterations in the activity of the reproductive neuroendocrine axis. However, they do indicate that increased NPY biosynthesis during food restriction may be involved in the inhibition of pulsatile GnRH/LH release.

Thesis (MScAgric)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: An experiment was conducted to determine the effect of the frequency of supplementary feeding on the production of South African Mutton Merino (SAMM) ewes grazing wheat stubble. One hundred and sixty ewes were randomly divided into two groups that consisted of four groups each. Eight camps were grazed for 138 days during which lambing occurred. Four groups of 25 ewes each grazed a 17 ha camp at a stocking density of 5.8 ewes/ha and four groups of 15 ewes each grazed a 12 ha camp at a stocking density of 5.0 ewes/ha. A combination energy/protein supplement was made available to the ewes as a lick. Two of the groups received no supplementary feed (control), two groups received 200 g/ewe/day, two groups received 400 g/ewe every second day and two groups received 600 g/ewe every third day. The smallest decrease in weight during the feeding period was observed in the ewe group that received supplementation every day as well as the ewe group that received supplementation every second day, but no significant differences were observed between these two groups. The smallest decrease in weight over the total feeding period was observed in the three ewe groups that received supplementation (P < 0.1), while the ewes that received none (control groups) lost the most weight during the same period. All supplemented groups performed significantly better than the unsupplemented control group in terms of the liveweight change over the feeding as well as the total period. No significant differences occurred in the lambing percentage, weaning percentage, birthweight, 42-day weight and survival rate of the lambs due to the different feeding regimes. It was concluded that supplementation to ewes every third day or every second day is an economically feasible option and will reduce labour and transport costs. In the second study the effect of stocking density on canola stubble composition and subsequently the production of SAMM ewes on this type of stubble was investigated. Forty-eight ewes were randomly divided into four groups that grazed canola stubble at a stocking density of approximately 1.5, 3.5, 5.5 and 7.5 ewes/ha for 152 days. The ewes did not receive any supplementation and were weighed every 14 days. Parturition occurred during the last week in March 1997 until the first week in May 1997, and the lambs were weighed at birth, and every 14 days thereafter. Stubble samples were collected from the paddocks during the first part of the trial (January and February) and at the end of the trial (April and May) by cutting ten replicate quadrates per paddock and were analysed for dry matter (DM), crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and in vitro digestibility of organic matter (IVDOM). The live weight of the ewes at a stocking density of 5.5 ewes/ha decreased significantly, while the ewes at a stocking density of 1.5 ewes/ha gained weight. The ewes at a stocking density of 3.5 ewes/ha had the lowest weight loss (P = 0.01). Stocking density did not affect the birthweight of the lambs significantly. The CP concentration of the stubble decreased with an increase in stocking density, while the ADF and NDF concentration of samples were significantly higher at the higher stocking density. In the third study the supplementation of rumen inert fat or starch on the production of ewes grazing wheat stubble, was investigated. Fifty-six SAMM ewes were randomly divided into four groups of 14 ewes each, grazing the wheat stubble at a stocking density of 4.6 ewes/ha. Each group was supplemented with 250 gJewe daily for the last six weeks of pregnancy, which was increased to 360 gJewe during the first four weeks of lactation. Supplementation was supplied on Mondays, Wednesdays and Fridays for a 70-day period. The CP concentration of the supplement varied between 16.7 % and 19.6 %, while the total digestible nutrient (TDN) content varied between 52.0 % and 76.7 %. No significant difference (P > 0.05) occurred between the live weights of ewes during the last six weeks of pregnancy, the first four weeks of lactation, or the total feeding period. The ewes in the 50 % fat plus 50 % maizemeal group lost less weight (P :s; 0.08) during lactation than the ewes that received maizemeal as their main energy source. The study indicated that there was no significant advantage in the live weight change of the ewes during the experimental period, when compared to the group that received wheat bran (control group). In the fourth study the economic advantage of supplementation to SAMM ewes grazing wheat- or oat stubble were studied. Three hundred and sixteen ewes were divided into four flocks, of which two grazed oat stubble and two wheat stubble. Each of these four flocks was again subdivided into four subdivisions of which two subdivisions received supplementation and two none. Four subdivisions received 200 g/d for 83 days, and the other four subdivisions received 200 g/d for 44 days after which it was increased to 300 g/d for 37 days (81 days in total). The ewes were weighed monthly. The final bodyweight of the ewes that received supplementation was significantly higher than those that received none. Over the feeding period, the ewes that received supplementation had a significant lower weight loss in comparison to the ewes that did not receive supplementation. The 42-day weight of the lambs improved significantly due to supplementation, but no significant increase was indicated in the birthweight, weaning weight and survival rate of the lambs whose mothers received supplementation. In the fifth study the influence of supplementary feeding to ewes and creep feeding of their lambs on the production of both the ewes and lambs were studied. One hundred and sixty eight ewes were divided into two groups of 68 and 100 ewes that grazed a 12.9 and 18 ha camp respectively. Each of these ewe groups was subdivided into four groups of which two ewe groups received supplementation and two none. Within each ewe group two groups of lambs received creep feeding and two received none. A two (supplementation of ewes) by two (creep feeding of lambs) factorial design was used. Supplementation was supplied at 200 g/d for the first 69 days and 300 g/d for the next 120 days to ewes. Lambs received an average ofO.58 kg creep feed per day for 96 days. It was concluded that the live weight change (LWC) of the ewes during the experimental period was not affected significantly by creep feeding of their lambs. Ewes that received supplementation maintained higher live weights than their counterparts for most of the feeding period, although final weights at the end of the experimental period did not differ significantly. The average daily gain (ADG) of the lambs whose mothers received supplementation tended to be higher than that of mothers that received no supplementation, while the ADG of the lambs that received creep feeding was significantly higher than the lambs that received none. In the sixth study the carry-over effect of supplementation in the previous year on the production of the ewes in the following year was studied. Three hundred and sixteen ewes were divided into four flocks, of which two grazed oat stubble and two wheat stubble. Each of these four flocks was again subdivided into four subdivisions of which two subdivisions received supplementation and two none. Four subdivisions received 200 g/d for 83 days, and the other four subdivisions received 200 g/d for 44 days after which it was increased to 300 g/d for 37 days (81 days in total). The ewes were weighed monthly. Results indicated that birth status (lambs born per ewes mated) of lambs showed a tendency to increase in 1999 due to supplementation in 1998, while weaning status was not significantly affected. Due to multiple births in the supplemented groups, the birthweight and weaning weight of lambs was negatively affected by supplementation. The study concluded that supplementary feeding in the previous year did not have significant carry-over effects in the following year. However, the effect may have been influenced by the fact that mature animals were used in the study, while the pasture availability during the non-productive stage will also affect possible carry-over effects.
AFRIKAANSE OPSOMMING: 'n Eksperiment is uitgevoer om te bepaal wat die invloed van die frekwensie van byvoeding op die produksie van Suid-Afrikaanse Vleismerino (SAVM) ooie wat koringstoppel bewei, sal wees. Eenhonderd-en-sestig ooie is ewekansig in twee groepe verdeel wat bestaan het uit vier groepe elk. Die agt kampe is vir 138 dae bewei waartydens die ooie ook gelam het. Vier groepe bestaande uit 25 ooie het 'n 17 ha kamp teen 'n weidigtheid van 5.8 ooie/ha bewei en die ander vier groepe bestaande uit 15 ooie het 'n 12 ha kamp teen 'n weidigtheid van 5.0 ooie/ha bewei. 'n Kombinasie energie/proteïen aanvulling in die vorm van 'n lek is aan die ooie beskikbaar gestel. Twee van die groepe het geen aanvullende voeding ontvang nie (kontrole), twee groepe het 200 g/dag/ooi ontvang, twee groepe het 400 glooi elke tweede dag ontvang en twee groepe het 600 glooi elke derde dag ontvang. Die kleinste daling in liggaamsgewig tydens die voerperiode is waargeneem in die ooie wat elke dag sowel as elke tweede dag byvoeding ontvang het, alhoewel geen betekenisvolle verskille tussen dié twee groepe waargeneem is nie. Die kleinste daling in gewig tydens die totale voerperiode is waargeneem in die drie groepe wat byvoeding ontvang het (P < 0.1) terwyl die groepe wat geen byvoeding ontvang het nie (kontrole) die meeste gewig tydens dieselfde periode verloor het. Al die groepe wat byvoeding ontvang het, se liggaamsmassa verandering oor die voerperiode asook die totale periode was betekenisvol beter as die kontrole groep Geen betekenisvolle verskille is gevind by lampersentasie, speenpersentasie, geboortegewig, 42-dae gewig en oorlewing van lammers nie. Daar is bevind dat die byvoeding aan ooie elke derde of elke tweede dag ekonomies geregverdig is en 'n moontlike afname in arbeid- en vervoerkostes mag meebring. In die tweede studie is die invloed van weidigtheid op die samestelling van kanolastoppel en die produksie van SAVM-ooie op hierdie tipe stoppelondersoek. Agt-en-veertig ooie is ewekansig in vier groepe verdeel en het kanolastoppel teen 'n weidigtheid van ongeveer 1.5, 3.5, 5.5 en 7.5 ooie/ha vir 152 dae bewei. Die ooie het geen byvoeding ontvang nie en is elke 14 dae geweeg. Die ooie het gelam vanaf die laaste week in Maart 1997 tot die eerste week in Mei 1997. Die lammers is met geboorte geweeg en daarna elke 14 dae. Stoppelmonsters van die kampe is versamel gedurende die eerste deel van die studie (Januarie en Februarie) asook aan die einde van die studie (April en Mei) deur tien kwadrate per kamp te sny en is daarna ontleed vir droë materiaal (DM), ruproteïen (RP), suur bestande vesel (SBV), neutraal bestande vesel (NBV) en in vitro verteerbaarheid van organiese materiaal (lVVOM). Die liggaamsgewig van die ooie teen 'n weidigtheid van 5.5 ooie/ha het betekenisvol afgeneem, terwyl die ooie teen die weidigtheid van 1.5 ooie/ha toegeneem het in massa. Die ooie teen 'n weidigtheid van 3.5 ooie/ha het die kleinste gewigsverlies getoon (P = 0.01). Die geboortegewig van die lammers is nie betekenisvol deur weidigtheid beïnvloed nie. Die RP-konsentrasie van die stoppel het afgeneem met 'n toename in weidigtheid, terwyl die SBV en NBV -konsentrasie van die monsters betekenisvol hoër was by die hoër weidigtheid. In die derde studie is die byvoeding van rumen inerte vet of stysel aan ome wat koringstoppel bewei ondersoek. Ses-en-vyftig SAVM ooie is ewekansig in vier groepe van 14 elk verdeel en het koringstoppel teen 'n weidigtheid van 4.6 ooielha bewei. Elke groep het daagliks byvoeding teen 250 glooi tydens die laaste ses weke van dragtigheid ontvang, waarna dit vermeerder is tot 360 glooi tydens die eerste vier weke van laktasie. Byvoeding is op Maandae, Woensdae en Vrydae vir 70 dae voorsien. Die RP-konsentrasie van die byvoeding het gevarieer tussen 16.7 % en 19.6 % terwyl die totale verteerbare voedingstof (TVV) konsentrasie gevarieer het tussen 52.0 % en 76.7 %. Daar was geen betekenisvolle verskille (P > 0.05) tussen die liggaamsmassa van die ooie gedurende die laaste ses weke van dragtigheid, die eerste vier weke van laktasie, of die totale voerperiode nie. Die ooie in die 50 % vet plus 50 % mieliemeel groep het minder gewig (P ~ 0.08) gedurende laktasie verloor as die ooie wat mieliemeel as hulle hoof energiebron ontvang het. Die studie het getoon dat daar geen betekenisvolle toename in die liggaamsgewig van die ooie tydens die eksperimentele periode was in vergelyking met die groep wat koringsemels (kontrole) ontvang het nie. In die vierde studie is die ekonomiese voordeel van byvoeding vir SAVM ooie wat koringof hawerstoppel bewei het ondersoek. Driehonderd-en-sestien ooie is in vier groepe verdeel,waarvan twee hawerstoppel en twee koringstoppel bewei het. Elk van hierdie vier groepe is herverdeel in vier subdivisies waarvan twee byvoeding ontvang het en twee geen. Vier subdivisies het 200 gld vir 83 dae ontvang, terwyl die ander vier subdivisies 200 gld vir 44 dae ontvang het, waarna dit verhoog is na 300 gld vir 37 dae ('n totaal van 81 dae). Die ooie is maandeliks geweeg. Die finale liggaamsgewig van die ooie wat byvoeding ontvang het betekenisvol hoër was as die ooie wat geen byvoeding ontvang het nie. Tydens die voerperiode het die ooie wat byvoeding ontvang het 'n betekenisvolle laer gewigsverlies getoon in vergelyking met die ooie wat geen byvoeding ontvang het nie. Die 42-dae gewig van die lammers het ook betekenisvol toegeneem, maar geen verskil is waargeneem in die geboortegewig, speengewig en oorlewingstempo van lammers wie se moeders byvoeding ontvang het nie. In die vyfde studie is die invloed van byvoeding aan ooie en kruipvoeding aan hulle lammers op die produksie van beide die ooie en lammers bestudeer. Eenhonderd-agt-en-sestig ooie is onderskeidelik in twee groepe van 68 en 100 verdeel wat twee kampe van 12.9 en 18 ha respektiewelik bewei het. Elkeen van hierdie groepe is onderverdeel in vier groepe waarvan twee groepe byvoeding ontvang het en twee groepe geen. Binne elke ooi groep het twee groepe lammers kruipvoeding ontvang en twee geen. 'n Twee (byvoeding aan ooie) by twee (kruipvoeding aan lammers) faktoriaal ontwerp is gebruik. Byvoeding aan die ooie is verskaf teen 200 gld vir die eerste 69 dae en 300 gld vir die volgende 120 dae. Lammers het 0.58 kg kruipvoer per dag vir 96 dae ontvang. Daar is bepaal dat die liggaamsgewig-verandering van die ooie gedurende die eksperimentele periode nie betekenisvol beïnvloed is deur kruipvoeding van die lammers nie. Ooie wat byvoeding ontvang het het 'n hoer liggaamsgewig vir die grootste deel van die voerperiode gehandhaaf, alhoewel die finale gewigte aan die einde van die eksperimentele periode nie betekenisvol verskil het nie. Die gemiddelde daaglikse toename (GDT) van die lammers wie se moeders byvoeding ontvang het, het geneig om hoër te wees as die lammers wie se moeders geen byvoeding ontvang het nie, terwyl die GDT van die lammers wat kruipvoeding ontvang het was betekenisvol hoër as die lammers wat geen kruipvoeding ontvang het nie. In die sesde studie is die oordrageffek van byvoeding in die vorige jaar op ooie se produksie in die opvolgende jaar ondersoek. Driehonderd-en-sestien ooie is in vier groepe verdeel,waarvan twee hawerstoppel en twee koringstoppel bewei het. Elk van hierdie vier groepe is herverdeel in vier subdivisies waarvan twee byvoeding ontvang het en twee geen. Vier subdivisies het 200 gld vir 83 dae ontvang, terwyl die ander vier subdivisies 200 gld vir 44 dae ontvang het, waarna dit verhoog is na 300 gld vir 37 dae ('n totaal van 81 dae). Die ooie is maandeliks geweeg. Resultate het aangedui dat die geboortestatus (lammers gebore/ ooie gepaar) van lammers 'n tendens getoon het om toe te neem in 1999 as gevolg van byvoeding in 1998, terwyl speenstatus nie betekenisvol beïnvloed is nie. Byvoeding in 1998 het die geboortegewig en speengewig van lammers verlaag omdat dit 'n groter aantal meerlinggeboortes veroorsaak het. Die studie het bevind dat byvoeding in die vorige jaar nie 'n betekenisvolle oordrageffek in die volgende jaar teweeg gebring het nie. Die resultate mag egter beïnvloed gewees het deurdat volwasse diere in die studie gebruik is, terwyl die beskikbaarheid van weiding tydens die stadium wanneer die ooie nie gereproduseer het nie ook die moontlike oordrageffek kon beïnvloed het.

Thesis (PhD(Agric) (Animal Sciences))--University of Stellenbosch, 2006.
This project consisted of five studies. The objectives were to determine the essential amino acid (AA) requirements of growing woolled lambs (Merino and Dohne Merino) and the essential AA profile of duodenal digesta pre-dominantly derived from microbial protein. The limiting essential AA`s in high rumen degradable protein (RDP) diets to growing lambs, where microbial protein is the primary source of AA`s, were also identified. The first study determined the essential AA profile of duodenal protein on a high rumen degradable diet and evaluated the impact of dietary RDP concentration and source [true RDP vs. non-protein nitrogen (NPN)] on the AA composition of supplied in the duodenum. The first trial in this study evaluated the effects of increasing true RDP levels on the essential AA composition of duodenal protein primarily derived from rumen microbes. The lambs had free access to wheat straw and fresh water. The daily RDP supplements were administered in two equal doses into the rumens through rumen cannulas at 07:00 and 19:00. Duodenal digesta was extracted with 6h intervals through T-type cannulas, inserted proximally to the common bile duct. Sampling time was advanced 2h every day to obtain duodenal samples on every even hour of a 24h period after three days. As expected, deficient RDP limited the supply of essential AA`s in the iv duodenum. When the true RDP supplements increased, the duodenal flow of essential AA`s also increased concomitantly, but appeared to level off at the higher RDP levels. Despite the positive quantitative effects of true RDP supplementation on AA supply to the duodenum, the AA profile in the duodenum was unaltered. Consequently, the essential AA profile of duodenal protein of sheep receiving high RDP diets, where microbial protein is the primary source of AA`s in the duodenum, is relatively constant and insensitive to dietary RDP concentration. In the second trial the effects of RDP source (true RDP vs. NPN) on the essential AA profile of duodenal protein on high RDP diets were evaluated by substituting increasing amounts of urea for true RDP in isonitrogenous teatments. Higher NPN increments reduced the daily supply of essential AA`s in the duodenum. In corroboration of the first trial, the AA profile of the duodenal protein was very constant, irrespective of the RDP source. Since microbial protein is the major source of duodenal AA`s on high RDP diets, this study supports the view that microbial protein has a relatively constant AA profile, but microbial protein yield varies according to several rate limiting factors in the rumen. A constant microbial AA profile allows accurate estimates of microbial essential AA supply in the small intestine if microbial protein production and fluid and particulate outflow rates from the rumen can be accurately predicted. This allows the development of more accurate undegradable protein (UDP) supplementation strategies, based on the essential AA requirements of animals. In the second study growing male Merino and Dohne Merino lambs were slaughtered at different weights and body condition scores. The digesta was removed from the stomachs and intestines and every organ or body part were weighed to determine the whole empty body (WEB) composition. The WEB was partitioned into the carcass, internall offal (stomachs, intestines, organs and blood) and external offal (head, feet, skin and wool). No differences were apparent in the proportional weight distribution of similar body components of the same breed at different ages. In a comparison between breeds, the proportional weight contributions of the carcasses from both breeds to the WEB weight were remarkably similar at both slaughtering stages. The Dohne Merino lambs had proportionally larger internal offals and smaller external offals than the Merino lambs at both slaughters. Unless the essential amino acid compositions of the internal and external offals were identical to the carcass, the dissimilarities in weight and protein allocation to these two components within the WEB`s of Merino and Dohne Merino lambs imply a distinct WEB essential AA composition for each breed. The apparent digestibilities of dry matter (DM), crude protein (CP), energy, acid detergent fibre (ADF), neutral detergent fibre (NDF), fat and ash did not differ between Merino and Dohne Merino lambs. Energy retention was also similar for the two breeds, but the Merino lambs retained considerably more N than the Dohne Merino lambs. This may also impact on the respective amino acid requirements of the lambs. Since the Merino lambs utilise N more efficiently, they may have potentially lower essential amino acid requirements to achieve a similar growth rate. The WEB essential AA compositions of growing Merino and Dohne Merino lambs were determined in the third study. Based on the ideal protein concept, the WEB essential AA profile was accepted as representative of the AA requirements for growth. The use of a single body part as a representation of the WEB AA profile was also evaluated. Differences in the proportional weight and protein contribution of the three body components (carcass, internal offal and external offal) of the two breeds strongly suggested that the WEB AA composition of the breeds would differ, because of likely differences in the AA profiles of these components. The essential AA profiles of the carcasses from the two breeds were surprisingly similar. However, the essential AA compositions of the internal offal and external offal differed substantially from each other, as well as from the carcass. In addition, the internal offal and external offals of each breed had characteristic essential AA profiles. Inevitably, the WEB essential AA profiles of Merino and Dohne Merino lambs differed considerably. Only the leucine and phenylalanine concentrations in the WEB`s of Merino and Dohne Merino lambs did not differ. Significant differences in the concentrations of eight essential AA`s implied that the two breeds have different AA requirements for growth. The different AA compositions of the internal and external offal within each breed also illustrated that the use of a single body component, like the carcass, as a predictor of WEB essential AA composition contains considerable inaccuracies. The essential AA index indicated that the duodenal protein, primarily derived from rumen microbes, provided approximately 81 % of the qualitative AA requirements of growing lambs. During periods of sufficient availability of very low-quality forage, as the diet in this study simulated, microbial protein is not able to support maximum growth. The first two limiting AA`s (histidine and methionine) could not even support daily growth rates of 100 g/d. This is very low and stresses the need for effective undegradable AA supplementation under these conditions. Chemical scores identified histidine as the first limiting AA in high RDP diets (predominantly microbial protein), followed by methionine, leucine, arginine and phenylalanine. However, the requirements for histidine and arginine are frequently over estimated and these AA`s should actually be considered semi-essential, which could render methionine, leucine and phenylalanine the first three limiting AA`s to growing lambs receiving high RDP diets. Because of the limitations of static measurement systems for the determination of AA requirements, a more comprehensive evaluation method was introduced for determination of the limiting AA`s in duodenal protein of lambs on high RDP diets, in the fourth study. The fourth study focused on the identification of limiting AA`s to growing lambs being limit-fed a high RDP diet. The diet consisted primarily of soybean hulls, for its’ low rumen UDP content. Microbial protein production was calculated as 13 % of total digestible nutrient intake and complementary AA supplements prepared to simulate the WEB AA profile, determined in the previous study, in the small intestine. To eliminate the influence of the rumen on the AA supplements, the latter were infused into the abomasums via flexible tubing. Each essential AA was in turn removed from the control treatment (simulating the WEB composition) and the effect on N retention measured. When methionine or the branched-chain amino acids (BCAA`s) were removed from the infusate, N retention of the lambs was reduced. Consequently, methionine and at least one of the BCAA`s limited growth performance of young lambs when microbial protein was the predominant source of AA`s. The concomitant increased plasma concentrations of total AA`s when methionine or the BCAA`s were removed from the infusate corroborates the effects on N retention, since it indicates that AA utilisation was reduced when these AA imbalances were introduced. Amino acid imbalances had no effect on apparent DM, organic matter (OM) or NDF digestion, but N digestibility was reduced. The final study verified whether the BCAA’s were co-limiting the growth of lambs, or if any single BCAA was responsible for the limitation. Again the WEB AA profile of growing lambs was simulated in the small intestine via abomasal infusions to lambs receiving a soybean hull-based diet. Leucine, isoleucine and valine were individually or simultaneously removed from the infusate and the impact on N retention measured. On an individual basis valine had the largest negative impact on the efficiency of N utilisation. However, the simultaneous removal of the BCAA`s resulted in the lowest N retention, suggesting that valine might be limiting, but the three BCAA`s are more likely to be co-limiting in diets to growing lambs where microbial protein is the primary source of AA`s. Once again, neither DM, OM or NDF digestibility were affected by the AA imbalances. Nitrogen digestibility was, however, negatively affected by AA imbalances. This project succeeded in establishing the essential AA profile of duodenal protein in sheep receiving high RDP diets. The WEB essential AA compositions of growing lambs from two prominent sheep breeds in South Afica were then determined and the duodenal essential AA profile evaluated against the calculated AA requirements. Finally, the AA`s that limit growth in diets where microbial protein is the predominant source thereof were identified. These results contribute to the current knowledge of AA requirements in growing lambs, and highlight areas for future research, as discussed in the General Conclusion.

Diarrhoea ("scouring") in sheep increases the risk of faecal soiling of the breech ("dag") that in turn causes significant production losses for sheep producers and increases susceptibility of sheep to breech blowfly strike. The common causes of scouring in sheep of post-weaning age in Western Australia have not been well described. In a written questionnaire sent to sheep producers in the south west of Western Australia, about half of the respondents reported lamb, hogget and ewe flocks with moderate or severe dag. Flocks with moderate or severe dag were reported more commonly in the winter and spring months in all age groups. Young sheep and mated ewes were most susceptible to moderate or severe dag. The utilisation of professional worm control advice and parasite management tools did not reduce the risk of moderate/severe dag. A study conducted at an abattoir showed that large strongyle worm egg counts (WEC) were frequently identified in lamb lines but were much less common in adult lines. The relationship between WEC and scouring was not clear, suggesting that factors other than large strongyle infections were important, particularly in adult sheep. The low WEC and seasonal scouring pattern observed in adult sheep was consistent with the larval hypersensitivity scouring syndrome and/or factors related to green pasture as potential common causes of scouring in adult sheep. This observation was consistent with detailed investigations of flocks with "low WEC scouring" that found larval hypersensitivity scouring syndrome or factors associated with green pasture were the most likely causes of scouring in eight of the nine flocks examined. Large immature worm burdens were common and the scouring sheep had more fourth stage larvae than normal sheep. Treatment with a fully effective drench and an ivermectin controlled-release rumen capsule did not result in a reduction of faecal moisture content between three and seven weeks after treatment. The effects of dietary soluble non-starch polysaccharides were studied using carboxymethylcellulose (CMC) as a model. The CMC model was used to demonstrate that significant interactions between diet and strongyle larvae determined both faecal consistency and strongyle establishment. Sheep fed CMC had softer, looser and wetter faeces, but the factors that determined faecal consistency were complex. Establishment of T. colubriformis was significantly greater in sheep fed CMC suggesting that the environment within the gut may affect establishment of T. colubriformis in the small intestine. The findings suggested that dietary factors may interact with strongyle larvae to determine both worm establishment and severity of scouring. The results of the studies described in this thesis suggested that factors related to immature strongyle larvae, diet and the immune response interact to determine the severity of the scouring observed in sheep of post-weaning age in the south west of Western Australia.

Diarrhoea ("scouring") in sheep increases the risk of faecal soiling of the breech ("dag") that in turn causes significant production losses for sheep producers and increases susceptibility of sheep to breech blowfly strike. The common causes of scouring in sheep of post-weaning age in Western Australia have not been well described. In a written questionnaire sent to sheep producers in the south west of Western Australia, about half of the respondents reported lamb, hogget and ewe flocks with moderate or severe dag. Flocks with moderate or severe dag were reported more commonly in the winter and spring months in all age groups. Young sheep and mated ewes were most susceptible to moderate or severe dag. The utilisation of professional worm control advice and parasite management tools did not reduce the risk of moderate/severe dag. A study conducted at an abattoir showed that large strongyle worm egg counts (WEC) were frequently identified in lamb lines but were much less common in adult lines. The relationship between WEC and scouring was not clear, suggesting that factors other than large strongyle infections were important, particularly in adult sheep. The low WEC and seasonal scouring pattern observed in adult sheep was consistent with the larval hypersensitivity scouring syndrome and/or factors related to green pasture as potential common causes of scouring in adult sheep. This observation was consistent with detailed investigations of flocks with "low WEC scouring" that found larval hypersensitivity scouring syndrome or factors associated with green pasture were the most likely causes of scouring in eight of the nine flocks examined. Large immature worm burdens were common and the scouring sheep had more fourth stage larvae than normal sheep. Treatment with a fully effective drench and an ivermectin controlled-release rumen capsule did not result in a reduction of faecal moisture content between three and seven weeks after treatment. The effects of dietary soluble non-starch polysaccharides were studied using carboxymethylcellulose (CMC) as a model. The CMC model was used to demonstrate that significant interactions between diet and strongyle larvae determined both faecal consistency and strongyle establishment. Sheep fed CMC had softer, looser and wetter faeces, but the factors that determined faecal consistency were complex. Establishment of T. colubriformis was significantly greater in sheep fed CMC suggesting that the environment within the gut may affect establishment of T. colubriformis in the small intestine. The findings suggested that dietary factors may interact with strongyle larvae to determine both worm establishment and severity of scouring. The results of the studies described in this thesis suggested that factors related to immature strongyle larvae, diet and the immune response interact to determine the severity of the scouring observed in sheep of post-weaning age in the south west of Western Australia.

The aim of this study was to evaluate the Small Ruminant Nutrition System (SRNS) model’s performance predictions for lambs under South African conditions using growth and body composition data of early- (Dorper) and late-maturing (South African Mutton Merino), indigenous sheep breeds. The Cornell Net Carbohydrate and Protein System (CNCPS) biological model has consistently been modified to include recent information. This has led to the development of the SRNS model, but up to now the SRNS model has only been validated with European sheep breeds under European conditions. Thirty two Dorper, 16 male and 16 female lambs, and 36 South African Mutton Merino, 18 male and 18 female lambs, were fed a grower diet for the experimental period of 60 days. Three groups of lambs of each breed were slaughtered as the lambs reached pre-determined target weights. The first group of 24 animals (slaughter group 1) was slaughtered at the onset of the experiment at a live weight of 20 kg. With the second group (slaughter group 2) the South African Mutton Merinos were slaughtered at an average weight of 35 kg and the Dorpers at an average weight of 30 kg. The last group (slaughter group 3) had an average weight of 50 kg for the South African Mutton Merinos and 40 kg for the Dorpers at slaughter. Using the data from this trial, predictions of the average daily gain (ADG), feed intake (DMI), empty body gain and the composition of the empty body gain were used to evaluate the model. The animals were divided into three slaughter groups, based on growth stage, for the determination of body composition data. Energy value of gain (EVG), fat and protein content on a shrunk and empty body weight basis were compared with the corresponding values predicted by the SRNS. Growth composition of the lambs was determined by dividing them into two growth periods. Average daily gain and DMI were evaluated in the experiment, and results compared to the mean ADG and DMI predictions obtained from the SNRS model. Two different equations were compared to estimate EVG and two sets of coefficients were also compared for the EVG. Five different equations were compared to estimate the efficiency of conversion of metabolisable energy (ME) to net energy (NE) for gain, kg. The correction factor to adjust for the increase in the size of the visceral organs as nutrient intake increases and the coefficient for the effect of gender on maintenance requirements were tested for relevance of use in the SRNS. Overall, based on these evaluations it appears that the original SRNS model gave the best predictions when compared to any of the modifications tested. With regards to ADG the model over-predicts the requirements of the lambs in the early growth stage and under-predicts the requirements of the lambs in the later growth stage. The DMI predictions that were made using the original SRNS were accurate. The evaluation of the SNRS predictions in relation to the composition of gain indicated that this model over-predicted both the fat and the protein content of gain. The predictions were accurate, however the precision was low. The low precision was probably due to the lack of variation in the measured range of fat and protein content of gain. Before field application further studies and adjustments to the SRNS model is required, especially with regard to predictions on the fat and protein content of gain and over or under predictions of ADG during different growth stages of Dorper and South African Mutton Merino lambs.
Dissertation (MSc)--University of Pretoria, 2013.
gm2014
Animal and Wildlife Sciences
unrestricted

Lamb survival and productivity from birth to weaning and lamb postweaning management harvest are areas that the US sheep industry needs to become more efficient at to remain profitable. Western white-faced ewes were supplemented HIGH (12.5% rumen by-pass protein, 880 IU/kg of supplemental Vitamin E, 176 ppm chelated Zn, and 72.7 mg/kg chlortetracycline) or LOW (7.56% rumen by-pass protein, with no supplemental Vitamin E, chelated Zn, or chlortetracycline) supplements at 0.227 kg•ewe -1•d -1 during late gestation. Ewes of different age and body condition scores were individually supplemented for 29 d prior to expected lambing. Thereafter, each ewe was mass fed the appropriate supplement until lambing. In Experiment 3, approximately 600 ewes were group fed HIGH or LOW supplements over 2 yr. Differences in antibody transfer from ewe to lamb were detected in supplemented ewes of different age (P < 0.10); however, lamb production was not different (P > 0.10) for all 3 experiments. To investigate lamb post-weaning management, terminally sired lambs (n = 72) were randomly assigned to 1 of 4 backgrounding treatments. Lamb backgrounding treatments were: ad libitum access to 80% alfalfa: 20% barley pellets (PELLET); cool season grass paddock grazing (GRASS); remain with ewe flock on fall dormant range (LATE WEAN); wean for 96 h and returned to ewe flock on dormant range (RANGE). Background treatments were applied for 29 d. Thereafter, lambs were finished on a corn based diet. Lamb BW and ultrasound measurements were taken at weaning, after background treatment, after feedlot step-up and at the conclusion of the finishing period. Pen intake was measured. Lambs backgrounded on PELLET were heavier (P < 0.10) than all other treatments after the backgrounding period and at the end of the feedlot period. Lambs backgrounded on PELLET had the greatest intakes and ADG (P < 0.10) during the feedlot period. At beginning and end of the feedlot period, PELLET and GRASS lambs had larger (P < 0.05) LM areas than RANGE and LATE WEAN treated lambs. Under the condition of the studies, late gestational supplements did not improve ewe productivity and backgrounding treatments on dormant range diminished feedlot productivity.

11 pp.
This publication contains information about browse utilization by ruminant animals. It provides information about the rangelands in Arizona, the nutritional quality of browse, effects of drought and tannin and how to overcome them.

There is evidence from a number of species that body condition or fatness plays a role in the regulation of energy balance, through a direct effect on voluntary food intake (VFI). However, since differences in body condition are frequently confounded with differences in previous nutrition, this study investigated the role of both factors in the control of VFI in sheep. In ewes grazing autumn pastures, there was a negative effect of body condition on VFI, but no independent effect of the previous level of nutrition. However, there was an interaction between the effects of body condition and herbage availability on intake, since VFIs of fat ewes differed with sward height while VFIs of thin ewes did not. The effect of early nutrition on VFI in growing lambs was studied in an experiment where ewes were given either a restricted or adequate level of nutrition in late pregnancy and early lactation. Mean live weight and gut development at weaning were reduced in lambs whose nutrition was restricted during both pregnancy and lactation, but subsequent VFI was not affected. Feeding behaviour was investigated in fat and thin sheep eating a pelleted diet. Thin ewes had higher intakes and spent more time feeding that fat ewes, but the number of meals and rate of ingestion during meals was the same. Both fat and thin ewes increased meal frequency and ingestion rate when food access time was reduced. Differences in VFI were found to persist longer than differences in body condition. Basal plasma insulin concentrations and those measured following an exogenous insulin challenge were both higher in sheep that had remained fat, than in sheep that had previously been thin. This is consistent with the hypothesis that insulin may provide a long-term negative feedback signal to the brain in fat animals, resulting in lower VFIs.

Feeds often contain molybdenum (Mo) and sulfur (S) in excess of recommended allowances for adequate copper (Cu) absorption by ruminant livestock. Two randomized-block experiments were conducted using lambs given a cereal-based diet (90% of dry matter (DM) intake), containing 8 mg Cu, 0.7 mg Mo and 2.1g S per kg DM, that was either unsupplemented or supplemented with ammonium molybdate or sodium sulfate alone or in combination, to determine the effects of Mo, S and Mo+S on growth, hematology, serum Cu and Mo concentrations and reproductive function. Short term intake (4 weeks) by rams, aged 18 and 20 weeks, of 26 mg Mo alone or in combination with 2g S per kg DM, had no effect on growth, hematology or the concentration of total Cu in serum (TCu). However, supplemented groups had lower (P<0.05) concentrations of serum Cu soluble in trichloroacetic acid (TCA-Cu), but the group given Mo+S had the highest (P<0.05) concentration of serum residual Cu (RCu). Luteinizing hormone (LH) peak amplitude was affected by age*diet interaction (P<0.05), because of high amplitude LH peaks in the serum of lambs, aged 24 wks, given Mo alone. Testosterone serum secretory profiles did not differ among diet groups, but testosterone peak frequency was higher (P<0.05) for older ram lambs. Long term intake (32-39 wks) by ewe, ram and wether lambs (gonadal influence) of 12 mg Mo, or 2g S alone or combined per kg DM also had no effect on hematology or TCu. Food intake and liver weights were higher (P<0.05), but TCA-Cu was lower (P<0.05) for groups given S. Serum concentrations of total Mo (TMo) were higher (P<0.05) for Mo-supplemented groups, but RCu was highest only for the Mo+S group. Growth was affected by Mo*S*gonadal influence*time interaction (P<0.05); until autumn, the body weight of Mo-supplemented groups were higher than those of ram and wether lambs given Mo+S. Ovarian or testicular functions were delayed more severely for Mo- than Mo+S-supplemented groups. Mean concentrations of LH were affected by Mo*S*gonadal influence*time interaction (P<0.05); the mean LH values of Mo-supplemented ram and ewe lambs were higher than the Mo+S-supplemented group, whereas a reverse trend was observed for wether lambs. The amplitude of LH peaks was affected by Mo*S*gonadal influence*time interaction (P<0.05); for ram lambs, LH peak amplitude was higher for Mo than Mo+S-supplemented groups, whereas for wether and ewe lambs the reverse trend was noted. Mean concentrations of serum Cortisol and Cortisol peak amplitude were affected by Mo*S interaction (P<0.05); the mean Cortisol concentration and peak amplitude for the Mo-supplemented group were higher than those for the Mo+S-supplemented group. The frequency of LH and Cortisol peaks did not differ (P>0.10) among diet groups. In conclusion, Mo supplementation of cereal-based diets containing a high concentration of Cu did not adversely affect lamb growth. However, the effect of high dietary Mo on reproductive function appears to depend on the dietary level of S and the induction of high serum RCu (thiomolybdate). Further investigations on the effects of Mo and thiomolybdate on endocrine function may provide a nutritional basis for improving reproductive efficiency in ruminants.
Land and Food Systems, Faculty of
Graduate

Antigen-specific and polyclonal serum immunoglobulin G (IgG) concentrations were measured in control (Con), vitamin A-deficient (A-def), and vitamin A-repleted (A-rep) lambs. In Trial, I ewe lambs were injected with primary and secondary antigenic challenges of ovalbumin (1mg) and lysozyme (.1mg). The A-def lambs were then repleted with vitamin A and all lambs were injected with primary and secondary antigenic challenges of human gamma globulin (HGG) (.1mg). In Trial II Con and A-def wether lambs were given primary and secondary antigenic challenges of ovalbumin (20μg). Half of the A-def lambs were then repleted with vitamin A. All lambs were subsequently given a primary and secondary challenge of HGG (20 μg). Spleen wt were similar for all treatments in Trial I while A-def V lambs in Trial II had greater spleen wt (P<.01) than Con or A-rep lambs. Polyclonal serum IgG concentrations were unaffected by treatment in Trial I while in Trial II concentrations were greater (P<.05) in the A-def lambs during the HGG challenge period. Antigen-specific IgG concentrations in both trials tended to be greater in the Con lambs towards the end of both the ovalbumin (Trial I and II) and lysozyme (Trial I) challenge periods. Control and A-rep lambs in Trial I responded similarly to the HGG challenges. In Trial II both the A-def and A-rep lambs had lower (P<.10) HGG specific serum IgG concentrations on the last 3 wk of the HGG challenge period as compared to A-def lambs. Humoral immune function appears to be impaired in A-def lambs and a 2-wk repletion period was not sufficient in this study to restore humoral immune function to normal levels.
Ph. D.

Transactions of magnesium (Mg) along the gastrointestinal tract and the effect of change in potassium (K) intake were recorded in two in vivo experiments in sheep and cattle. Additional information on the sensitivity to K intake was obtained by comparing Mg transport and electrochemical properties of isolated rumen epithelia of sheep and cattle in 4 additional in vitro experiments. The experiment described in Chapter 2, and performed in sheep housed indoors in metabolic crates, investigated the compensatory capacity of the intestine to respond to the reduction in Mg absorption from the stomach as a consequence of increase in K intake. The animals were equipped with a ruminal cannula and two intestinal cannulae (duodenum and ileum) and flow of digesta was measured by the addition of two indigestible markers, chromium ethylenediaminetetra-acetic acid (Cr-EDTA) and ytterbium acetate (Yb). The animals were infused in a Latin square design for periods of 10 days with a solution of K bicarbonate that provided between 15 and 47 g of K/day. The diet consisted of a 50:50 combination of concentrates plus lucerne hay that provided around 3.7 g of Mg per day and 15 g of K per day. After 5 days of infusion samples of feed, faeces, urine and plasma were collected and analysed for Mg and K content. After 6 days of infusion, samples of duodenal and ileal flow were obtained. The treatments reproduced the detrimental effect of K on Mg absorption, especially in the rumen; a rise in K intake from 15 to 23 g/day reduced total Mg absorption from the gastrointestinal tract from 1.36 to 1.23 g/day, further increase in K intake to 38 and 47 g/day reduced absorption to 1.12 and 1.05 g/day, an overall reduction of around 50% in Mg apparent availability. Magnesium was mainly absorbed in the stomachs and large intestine with the small intestine a site of net secretion. Most of the reduction in Mg absorption with increase in K intake occurred in the stomachs, reducing from 1.86 to 1.11 g/day. A compensatory reduction in the net secretion of Mg from the intestines (small and large) was observed. This compensation was largely due to reduction in net secretion from the small intestine, from 0.85 to 0.22 g/day, rather than an increase in net absorption from the large intestine, although both segments acted synergistically. Results also suggested significant individual variation in plasma Mg concentration, urinary Mg excretion and in the flow and absorption of Mg along the gastrointestinal tract. It was suggested that most of that variability was due to genetic factors. Differences between species (cattle and sheep) were pursued during the course of the experiment described in Chapter three. Four triple cannulated rams and 3 triple cannulated dry cows were placed in metabolic crates, fed daily fresh-cut pasture and infused, in a total randomised design that provided the equivalent of an intake of 30,40 and 50 g of K per kg dry matter intake (DMI) per day. Solutions of K (as K bicarbonate) and markers (CrEDT A and Yb acetate) were infused continuously for a period of 10 days; after 5 days of infusion samples of pasture, faeces, urine and plasma were collected and analysed for Mg and K content. After 6 days of infusion, samples of duodenal and ileal flow were obtained. Total feed offered, refusals and water consumption were recorded daily. Results showed a greater sensitivity of cattle to the increase in K supply. A rise in K supply from 30 to 40 g per kg DMI/day reduced Mg absorption by almost 50% from 0.32 to 0.16 g per kg DMI/day, whereas only the highest treatment dose (50 g of K per kg DMI/day) produced the same deleterious effect in sheep. The absorption of Mg occurred mainly in the stomachs and large intestine; in contrast the small intestine was a site of net secretion in both species. The addition of K slightly reduced the rate of Mg absorption from the rumen, especially in cattle. Similarly, net Mg secretion within the intestines increased with increasing K intake in both species, only to be counterbalanced by a greater Mg absorption from the large intestine. The large intestine in both species (sheep and cattle) reduced faecal losses of Mg but was unable to fully compensate for the reduction in Mg absorption from the stomach or the greater net Mg secretion observed at the small intestine. Differences between species in water content of the faeces were observed to be mainly related to the moisture content of the digesta that reached the ileum rather than a result of differences in absorption in the large intestine. More evidence of species differences in Mg transport and of sensitivity to K intake were obtained by using isolated rumen epithelia and the Ussing chamber technique. Transport and electrophysiological properties of the tissues were observed in standard conditions and by adding different K concentrations to the mucosal side. Under standard conditions and open-circuit voltage, sheep isolated rumen epithelia had greater transmural potential difference (PDt), and lower conductance (Gt) but similar short-circuit current (Isc) than those from cattle. These results suggested that the rumen epithelium of cattle is leakier than that of sheep. Measurement of the transport of Mg showed that isolated rumen epithelia of cattle transported more Mg and was saturated at higher Mg concentrations (12 vs 4 mM) than sheep epithelia. These differences in Mg influx (transport from mucosa to serosa) were also observed in studies of Mg transport using stable isotopes. Magnesium influx (transport from mucosa to serosa) from the isolated rumen of cattle was greater than in sheep (57.5 ± 12.72 vs. 17.3 ± 12.72 nmol.cm⁻².h⁻¹); however this was counterbalanced by a greater Mg efflux (transport from serosa to mucosa) of 48.1 ± 12.72 vs. 9.9 ± 12.72 nmol.cm⁻².h⁻¹, for cattle and sheep respectively, when mucosal K concentrations were around 25 mM. A increase in K concentration on the mucosal side enhanced transmural potential difference (PDt) and short-circuit current (Isc) to a greater extent in sheep than in cattle, suggesting a greater effect of K on sheep than on cattle epithelia. On the other hand, the transport of Mg measured by stable isotopes suggested that net absorption of Mg (7.4 ± 12.72 vs. 11.1 ± 12.72 nmol.cm⁻².h⁻¹) in sheep epithelia was similar at 25 and 50 mM of K on the mucosal side, whereas net Mg influx in cattle was largely depressed as a consequence of a reduction in Mg influx (mucosa to serosa) from 57.7 ± 12.72 to 2.9 ± 12.72 nmol.cm⁻² h⁻¹ together with a constant Mg efflux (serosa to mucosa) 48.1 ± 12.72 and 41.2 ± 12.72 nmol.cm⁻².h⁻¹, presumably leaving through a paracellular shunt. However, this finding was based on date from a small size and caution should be applied to this conclusion. In conclusion, data collected from several comparative studies suggest differences in Mg apparent availability between sheep and cattle and also a greater sensitivity of cattle to an increase in K intake. This high sensitivity to K represents a great risk of hypomagnesaemia in dairy cattle in New Zealand where high K concentration is endemic in pastures. Most importantly, these results suggest that models for Mg metabolism in cattle should be based on measurements from cattle nutritional and physiological studies rather than on extrapolation from sheep studies.

My objectives were to determine if nutritional benefits occur when animals are offered foods with compounds -- alkaloids, saponins, and tannins - that are potentially complementary. I hypothesized that food intake and digestibility increase when lambs consume plants such as alfalfa ALF that contain saponins or birdsfoot trefoil (BFT) that contain tannins when the basal diet is endophyte-infected tall fescue (TF) or reed canarygrass (RCG) both of which contain alkaloids. I predicted that the nutritional status of lambs would be enhanced if basal diets of alkaloid-containing grasses were supplemented with ALF or BFT. Lambs fed a basal diet of either endophyte-infected TF or RCG ate more food and consequently digested more dry matter, energy and nitrogen when supplemented with ALF or BFT. Lambs ingested more dry matter and digested more nutrients when fed a basal diet of RCG than one of TF, and supplementing with ALF and BFT was more beneficial for lambs fed TF than for lambs fed RCG. Increased intake of digestible nutrients was due to greater intake when lambs were offered more than one food, not due to an increase in digestibility. In pen trials meant to complement the field trials, lambs were offered an alkaloid-containing (either gramine or 5-methoxy-N,N-dimethyltryptamine) total mixed ration and supplemented with a food that contained saponins or tannins. All rations were isocaloric (3.3Mcal/kg) and isonitrogenous (14% CP). Lambs fed a ration with either alkaloid and offered a food containing saponin digested approximately the same amount of dry matter, energy, nitrogen, and NDF as lambs not offered saponin. When lambs were fed a ration with either alkaloid and supplemented with food that contained tannins, tannin consumption adversely affected dry matter, energy, and NDF digestibility, but lambs offered food with tannins increased dry matter intake, and as a result, they digested the same amount of dry matter, energy, and NDF as lambs not offered the food with tannins. Lambs offered tannin digested and retained more nitrogen than lambs not offered tannin. These findings indicate a nutritional advantage for sheep eating mixtures as opposed to monocultures of foods with different profiles of secondary compounds and nutrients.

Invitro synthesis and degradation capabilities and the cathepsin D activity of the skeletal muscles of experimentally induced Selenium-Vitamin E deficient lambs were investigated. Twenty-one Dorset x Coopworth x Suffolk lambs were blocked by weight and assigned to one of the following treatments: 1) a basal diet of 85% whole shelled corn and 15% mixed grass hay plus a mineral supplement that was low in Se and E (-Se-E), 2) the basal diet and deficient mineral mixture as fed in treatment 1 with the addition of a casein encapsulated fat supplement (-Se-E+fat), 3) the basal diet plus a mineral mixture which contained supplemental Se and E (+Se+E). Upon completion of the feeding trial, lambs which had been receiving the -Se-E treatment had the greatest body and individual muscle weights. The -Se-E+fat treatment had the lowest degradation rates and the highest synthesis rates. Cathepsin D activity was found to be lowest in the -Se-E+fat treatment. The -Se-E treatment was observed to have the highest degradation rate and the next highest synthesis rate indicating an increased rate of muscle turn-over. In all cases, the degradation rates were positively correlated with cathepsin D activity.
Master of Science

To investigate the whole body metabolism of selenium (Se), isotope kinetic studies were undertaken in which indwelling catheters were implanted in the jugular veins of pregnant and nonpregnant ewes as well as the inferior vena cava and saphenous veins of 110-120 day (d) old ovine fetuses. A single injection of ⁷⁵Se-sodium selenite was administered and blood samples were obtained at various times. A 5 d Se balance trial, which commenced on the day of tracer experiment, was also undertaken. The plasma ⁷⁵Se specific activity data were used for determining the kinetic parameters of Se metabolism and the placental transfer rates. Using the Se balance and tracer data the net absorption and the fecal losses of Se were calculated. The fractional rate constants and T½ Se utilization in individual tissues were estimated by sacrificing the ewes and the fetuses at different times after the tracer injection and determining the tissue ⁷⁵Se specific activities. The effect of Se deficiency on the kinetics, placental transfer, net absorption and tissue metabolism was studied in a similar manner by feeding the ewes with Se deficient rations. The mean plasma Se concentrations in the positive nonpregnant and pregnant ewes were 142 187 ng/ml and were significantly higher than Se and the corresponding values (82 and 69 ng/ml) in the Se deficient ones respectively. The plasma Se levels in the Se positive fetuses (46 ng/ml) were not significantly different from the deficient ones (53 ng/ml). The irreversible disposal (ID) rates of Se were 7 ug/d/kg body weight (B.W.) in both nonpregnant and pregnant ewes, whereas, these values declined to 2 ug/d/kg B.W. under deficiency conditions. The ID values in the Se positive and deficient fetuses were 20 and 11 ug/d/kg B.W. respectively. These results indicated that the plasma Se turnover was lower in Se deficient animals than in the positive ones and that the fetuses had a higher turnover than adult ewes irrespective of the maternal Se status. Values for net Se absorption (% Se intake) and fecal Se losses (ug/d) in the Se positive nonpregnant ewes were 51% and 272 ug/d versus 97% and 25 ug/d in the Se deficient ones. The corresponding values for the Se positive pregnant ewes were 56% and 241 ug/d as against 84% and 27 ug/d in the deficient ones. These results suggested that the efficiency of net Se absorption expressed as the percent of Se intake decreased with increasing Se intakes and that the fecal route exerted a homeostatic control on Se metabolism in ewes. The tissue Se concentrations were significantly higher in the Se positive animals than in the deficient ones, whereas, the tissue fractional rate constant values were higher in the Se deficient animals than in the positive ones. These results implied that the tissue Se concentrations were significantly decreased under Se deficiency conditions and that the Se turnover was higher in tissues when the dietary Se intake was minimal. The placental transfer studies showed that there was a bidirectional exchange of Se across the placenta. The placental Se transfer rates from ewe to fetus declined from 53 ug/d in the positive ewes to 29 ug/d in the deficient ones. The rate of Se transfer from fetus to ewe also decreased from 24 ug/d in the positive ewes to 12 ug/d in the deficient ones. The net placental Se transfer was found to be reduced under conditions of decreased maternal dietary supply. The nutritional implications of Se status of the pregnant ewes on the availability of the trace mineral to the fetus have been discussed.
Land and Food Systems, Faculty of
Graduate

There is little information on nutrient requirements for sheep raised in Brazil, so it is important to have more research in this area because a large number of publications is necessary for developing a table of Brazilian nutritional requirements for sheep. Thus, the present investigation was carried out to determine the body composition and protein and energy requirement for Santa Ines lambs. The experiment was conducted in the Department of Animal Science, Federal University of Sergipe. Twenty four no castrated Santa Ines lambs with an average age of three months and average live weight of 18.7 Kg, were randomly assigned to four treatments which were: corn silage; elephant grass silage + 15% of corn meal; area of sweet potato silage + 15% of corn meal; and robin + 15% corn meal, in a randomized block design. After an adaptation period of 14 days, an animal was randomly selected from each treatment and slaughtered to serve as reference for the estimates of empty body weight (EBW) and initial body composition of the remaining 20 lambs, totaling four treatments with five repetitions. The animals were slaughtered when they reached 30 kg live weight. Samples of blood, guts, organs, head, leather, legs, muscle, bone and fat from the left half carcass were collected to determine and estimate the amounts of nutrients in the EBW of the animals. The results were statistically analyzed using Proc Anova and Proc Reg using the statistical package SAS (2001). Regression analysis was made by the model y = a + b * X. The specific regression equations for each treatment did not differ (P < 0.01) by F test, so an overall regression equation for the EBW as a function of live weight was adopted, and the logarithm content of water, protein fat and energy in function of logarithm EBW lambs. The protein content of the empty body of the animals increased with increasing body weight, which is probably connected to the fact the animals are slaughtered aged solids that muscle development was still at a growing pace. The fat content in the empty body weight increased simultaneously with the increase of energy of body weight 15-30 kg, ranging from 57.88 to 243.10 g / kg EBW. The total net energy requirements of lambs rose with the increase in body weight from 15 to 35 kg, because when animals are in the final stages of growth occur with an increase in energy requirements with increasing body weight. The body content and requirements of protein and energy rose with increasing body weight of male sheep. Dietary protein and energy requirements are higher than those found in the NRC (2007).
Existem poucas informações sobre requerimentos nutricionais para ovinos criados no Brasil, de modo que é importante que se tenha mais pesquisas nessa área, pois é necessário um grande número de publicações para que possa se desenvolver uma tabela de exigências nutricionais brasileira para ovinos. Dessa forma, o presente trabalho foi realizado objetivando determinar a composição corporal e as exigências de proteína e energia para cordeiros da raça Santa Inês. O experimento foi realizado nas dependências do Departamento de Zootecnia da Universidade Federal de Sergipe. Foram utilizados 24 cordeiros não castrados da raça Santa Inês com idade média de três meses e peso vivo inicial médio de 18,7 Kg, que foram distribuídos aleatoriamente em quatro tratamentos, os quais foram: silagem de milho; silagem de capim-elefante + 15% de fubá de milho; silagem da parte aérea da batata doce + 15% de fubá de milho; e silagem de sabiá + 15% de fubá de milho, em um delineamento em blocos casualizados. Após um período de adaptação de 14 dias foi selecionado aleatoriamente um animal de cada tratamento e abatidos para servirem como referência para as estimativas do peso do corpo vazio (PCVZ) e da composição corporal inicial dos 20 cordeiros remanescente, totalizando assim quatro tratamentos com cinco repetições. Os animais foram abatidos quando atingiram 30 kg de peso vivo. Foram coletadas amostras do sangue, vísceras, órgãos, cabeça, couro, patas, do tecido muscular, ósseo e adiposo da meia-carcaça esquerda para determinar e estimar as quantidades dos nutrientes no PCVZ dos animais. Os resultados foram analisados estatisticamente por meio de Proc Anova e Proc Reg utilizando-se o pacote estatístico SAS. A análise de regressão foi feita pelo modelo y = a + b*X. As equações de regressão específicas para cada tratamento não diferiram entre si (P<0,01) pelo teste F, portanto adotou-se uma equação geral de regressão para o PCVZ em função do peso vivo e do logaritmo do conteúdo de água, proteína, gordura e energia em função do logaritmo do PCVZ dos cordeiros. O conteúdo de proteína no corpo vazio dos animais aumentou com a elevação do peso vivo, o que provavelmente, está ligado ao fato de os animais terem sidos abatidos com idade em que o desenvolvimento muscular se encontrava ainda em ritmo crescente. O conteúdo de gordura no peso de corpo vazio aumentou simultaneamente ao de energia com o aumento do peso vivo de 15 a 30 Kg, variando de 57,88 para 243,10 g/Kg PCVZ. As exigências de energia líquidas totais dos cordeiros duplicaram com o aumento do peso vivo de 15 para 35 Kg, pois quando os animais estão na fase final de crescimento verificam-se um incremento nas exigências energéticas com o aumento de peso corporal. O conteúdo corporal e as exigências de proteína e energia se elevaram com o aumento do peso vivo de cordeiros Santa Inês. As exigências dietéticas de proteína e energia são superiores aos encontrados no NRC (2007).

Sheep farming in northeastern Brazil is characterized as a sideline subsistence, requiring technologies that provide better productivity of these animals. In this aspect, called alternative food may to some extent improve the nutrition and animal nutrition. Thus the cassava, a liquid product resulting from the pressing of manioc, may be included in the diet of small ruminants as a food energy. Therefore the objective of this study was to evaluate the effect of adding different levels of cassava in the diet of sheep on consumption, performance, carcass characteristics of lambs Santa Inês feedlot. The experiment was conducted in an experimental field of Embrapa Coastal Tablelands, located in the municipality of Frei Paulo - SE. We used 32 lambs uncastrated Santa Ines with average weight of 24.76 kg and average age of 167 days. Diets were formulated in relation 70% forage and 30% concentrate to meet nutritional requirements. All treatments were Tifton 85 hay (Cynodon spp.), Grounded maize (Zea mays) and concentrated differing by the inclusion of cassava in growing levels: 0 ml, 500 ml, 1000 ml and 1500 ml Manipueira. DM intake (% BW, kg/day and g/kg PV0, 75), the performance and carcass characteristics were not affected by treatments (P> 0.05), but water consumption was affected by the addition of cassava (P<0.05). The addition of 500mL from cassava reduces the water consumption of the lambs. The dry matter intake was not altered with the addition of cassava at any level studied. The inclusion of cassava wastewater in the diet of sheep not altered nutrient intake, weight gain and quantitative features of the carcass, however, the addition of cassava modified water consumption of animals that received the cassava wastewater.
A criação de ovinos no nordeste brasileiro é caracterizada como uma atividade secundária de subsistência, necessitando de tecnologias que proporcionem uma melhor produtividade desses animais. Nesse aspecto, alimentos chamados de alternativos podem, de certa forma, melhorar a alimentação e nutrição dos animais. Sendo assim a manipueira, um produto líquido, resultante da prensagem da massa de mandioca, pode ser incluso na dieta de pequenos ruminantes como um alimento energético. Para tanto, o objetivo do presente trabalho foi avaliar o efeito da adição da manipueira em diferentes níveis na dieta de ovinos, sobre o consumo, desempenho, características de carcaça de cordeiros da raça Santa Inês terminados em confinamento. O experimento foi conduzido em um dos campos experimentais da Embrapa Tabuleiros Costeiros, localizado no município de Frei Paulo SE. Foram utilizados 32 cordeiros não castrados da raça Santa Inês com peso médio inicial de 24,76 ± 3 kg e idade média de 167 dias. As dietas foram formuladas na relação 70% de volumoso e 30% de concentrado de forma a atender aos requerimentos nutricionais. Todos os tratamentos foram constituídos por feno de Tifton 85 (Cynodon spp.), rolão de milho (Zea mays) e concentrado, diferenciando-se pela inclusão de manipueira em níveis crescentes: 0 ml; 500 ml; 1000 ml e 1500 ml de manipueira. O consumo de MS (% PV, kg/dia e g/kg PV0,75), o desempenho produtivo e as características de carcaça não foram afetados pelas dietas (P>0,05), mas o consumo de água foi afetado pela adição da manipueira (P<0,05). A adição a partir de 500ml de manipueira diminui o consumo de água de cordeiros. O consumo de matéria seca não foi alterado com a adição da manipueira em qualquer nível estudado. A inclusão da manipueira na dieta de ovinos não alterou o consumo de nutrientes, desempenho ponderal e as características quantitativas da carcaça, entretanto a adição da manipueira modificou o consumo de água dos animais que receberam a manipueira.

Two metabolism trials were conducted with 15 wethers surgically equipped with duodenal and ileal cannulas to study the absorption of P and certain other minerals from swine waste and broiler litter. The effect of source and level of P on rumen cellulytic bacterial populations was also determined. Animals were fed a low P basal diet until serum inorganic P averaged 5.5 mg/dl, then randomly assigned to the following diets: low P basal alone, or supplemented with swine waste, broiler litter, dicalcium phosphate, or soybean meal. Trials consisted of a 7-d preliminary period, a 7-d collection of urine and feces and a 6-d sampling of duodenal and ileal digesta, and feces. Animals fed the waste diets tended to absorb more P than those fed the conventional supplements. Calculated by difference, sheep absorbed more P from swine waste and broiler litter than from dicalcium phosphate and soybean meal (P< .1). Less Ca was absorbed from the waste diets than from the conventionally supplemented diets (P< .05). Expressed as g/d, there was no difference in Mg absorption between waste and conventional diets. Sheep fed waste tended to digest more dry matter and a higher percentage of ADF in the large intestine. Lignin was primarily digested in the large intestine of all sheep. More cellulytic bacteria were isolated from the rumen of sheep fed the supplemented diets (P< .05). Both P intake and P recycling appear to be important influences on cellulytic bacteria in the rumen. Both broiler litter and swine waste appear to be good sources of P and Mg for ruminants.
Ph. D.

CAPES
Objetivou-se avaliar o efeito da inclusão de diferentes níveis de óleos funcionais extraídos da mamona (Ricinus communis L.) e da casca da castanha do caju (Anacardium occidentale L.) sobre consumo e digestibilidade de nutrientes, parâmetros ruminais e síntese de proteína microbiana em ovinos. Foram utilizados quatro ovinos machos, castrados, sem raça definida, fistulados no rúmen, com peso vivo médio de 49,1 kg em um delineamento experimental quadrado latino 4 x 4, sendo os tratamentos a inclusão de 2, 4 e 6 g/animal/dia de óleos funcionais e o tratamento testemunha sem a inclusão do óleo. Após 21 dias para adaptação dos animais, o experimento foi conduzido em quatro períodos de 20 dias, sendo 15 para adaptação a dieta e cinco para coletas de amostras e dados. A digestibilidade aparente dos componentes da dieta, e os parâmetros ruminais: amônia, açúcares totais, peptídeos e aminoácidos não foram influenciados pelos tratamentos. O pH apresentou efeito cúbico com maiores valores observados com suplementação de 4,7g/dia e o menor valor com 1,4 g/dia de óleos funcionais. Ao longo do dia, a concentração de açúcares apresentou efeito quadrático aumentando nas primeiras horas após a alimentação. Houve efeito linear ao longo do tempo para as concentrações de peptídeos no fluido ruminal de ovinos recebendo 2g/dia de óleos funcionais, para as concentrações de aminoácidos nos ovinos não suplementados com óleos funcionais e para amônia, neste mesmo tratamento com variação de 9,85 mg/dL à 25,29mg/dL. Da mesma forma, o pH ruminal também variou em função do tempo de forma linear após alimentação para todos níveis de suplementação, com aumento nas duas horas após arraçoamento seguindo de decréscimo por pelo menos 6 horas, e evidenciando menor valor de pH de 5,78. Não foi verificado alterações no consumo e balanço de nitrogênio, com valores médios de nitrogênio retido de 24,5 g/dia, correspondendo a 65,07% do nitrogênio ingerido. Os derivados de purina excretados corresponderam a proporção de 51% de alantoína e 48% de ácido úrico, xantina e hipoxantina e não evidenciaram alterações na síntese microbiana.
The objective of this study was to evaluate the effect of the inclusion of different levels of functional oils extracted from castor bean (Ricinus communis L.) and cashew nuts (Anacardium occidentale L.) on nutrient intake and digestibility, ruminal parameters and microbial protein synthesis in sheep. Four male, castrated, undefined, rumen fistulated sheep were used, with a mean live weight of 49,1 kg in a 4 x 4 Latin square experimental design, with treatments being included of 2, 4 and 6 g/animal/day of functional oils and the control treatment without the addition of the oil. After 21 days for adaptation of the animals, the experiment was conducted in four periods of 20 days, 15 for adaptation to diet and five for collection of samples and data. The apparent digestibility of dietary components and ruminal parameters: ammonia, total sugars, peptides and amino acids were not influenced by the treatments. The pH had a cubic effect with higher values observed with supplementation of 4,7 g/day and the lowest value with 1,4g/day of functional oils. Throughout the day, the concentration of sugars presented quadratic effect increasing in the first hours after the feeding. There was a linear effect over time for the concentrations of peptides in the ruminal fluid of sheep receiving 2g/day of functional oils, for amino acid concentrations in sheep not supplemented with functional oils and for ammonia, in this same treatment with a variation of 9,85mg/dL to 25,29mg/dL. In the same way, the ruminal pH also varied as a function of time in a linear way after feeding for all levels of supplementation, with increase in the two hours after feeding, followed by decreasing for at least 6 hours, and evidencing a lower pH value of 5,78. No changes were observed in nitrogen consumption and nitrogen balance, with mean values of nitrogen retained of 24,5g/day, corresponding to 65,07% of the ingested nitrogen. Excreted purine derivatives corresponded to the proportion of 51% allantoin and 48% uric acid, xanthine and hypoxanthine and did not show changes in microbial synthesis.

Vitamin B₁₂ deficiency has been difficult to diagnose, mainly due to the vitamin's lack of biological significance in serum in which it is usually assayed. This research has investigated the marker of vitamin B₁₂/cobalt (Co) deficiency in sheep, methylmalonic acid (MMA), in comparison with serum and liver vitamin B₁₂ concentrations in farm situations where vitamin B₁₂ deficiency is expected in order to establish more accurate reference ranges for serum and liver vitamin B₁₂, and MMA. In addition, an attempt was made to ascertain the vitamin B₁₂ requirements of preruminant (PR) lambs, and to determine whether metabolic demand for vitamin B₁₂ influences tissue concentrations. Furthermore, since the vitamin is active in biological tissues in form of its coenzymes, 5’ -deoxyadenosylcobalamin and methylcobalamin, a preliminary assessment of variation in the distribution of these coenzymes in liver in different situations has been sought. The first trial was set up to find out if the addition of propionate to the PR lamb's diet stimulated the uptake and/or storage of vitamin B₁₂ in the liver as a reflection of the need to deal with the incoming propionate. Sixteen ten day old lambs (Dorset Down/Coopworth cross-bred) were housed indoors soon after birth and fed on milk replacer. For half of the lambs 7.5 % (w:w) of the milk powder was replaced by propionate. Within each group, four lambs were treated with 250 µg vitamin B₁₂ twice weekly. Supplementation with vitamin B₁₂ increased liver concentrations from ~250 to ~900 nmol/kg fresh tissue, but there was no effect of propionate. Propionate addition did, however, result in increased plasma vitamin B₁₂ concentrations in vitamin B₁₂ supplemented groups, values being 3323 and 2355 pmol/l in propionate supplemented and control groups, respectively. This suggested that diet could influence plasma vitamin B₁₂ concentrations. An attempt was made to quantify the PR lamb's ability to absorb vitamin B₁₂ from the alimentary tract by comparing the ability of intra-muscular (IM) and oral vitamin B₁₂ to raise plasma and liver vitamin B₁₂ concentrations. Twenty-seven three to four day old lambs from a farm with marginal Co status were housed indoors and fed on milk replacer. They were divided into three groups: control (n=3), IM treatment (n=12) and oral treatment (n=12). The two treatment groups were further subdivided into five sub-groups. These received, respectively, 0.2 (n=3), 0.4 (n=2), 0.8 (n=2), 1.6 (n=2) and 3.2 µg OH-cbl/d (n=3). The oral groups received tenfold the amount of the comparable IM groups, on the assumption that if oral absorption of the vitamin is about 10 % both groups would show similar increases in plasma and liver vitamin B₁₂ concentration. None of the IM groups showed any significant change in plasma or liver vitamin B₁₂. In the oral groups only the group on the highest dose of vitamin B₁₂, viz 32 µg/d, showed increases in plasma and liver concentrations. It was concluded that either absorption of vitamin B₁₂ was greater than 10 % or that the vitamin was retained better when administered orally. The amount retained in the livers of the lambs in the highest oral group was calculated to represent ~ 7.5 % of the dose. In a follow-up 24 h trial, 14 of the above lambs were divided into three groups: Control (n=3), oral (n=6) and IM (n=5) treatment. The IM group received 3.2 µg OH-cbl and the oral group tenfold the amount as single doses at 0800 h. Blood samples were taken at regular intervals throughout the 24 h period and assayed for vitamin B₁₂, Vitamin B₁₂ concentrations in the IM group rose steeply within the first hour after injection to a concentration that was calculated to reflect 100 % uptake of the vitamin. It rose more slowly over about 8 h in the oral group. From the area under the curve absorption of the oral dose was estimated to be ~ 7 %. The next experiment involved a farm where Co deficiency had been reported previously. In the first year, 50 pregnant two-tooth Half-bred ewes were divided randomly into two groups of 25. One group received a Co bullet plus 1000 µg OH-cb1 IM, the other group remained unsupplemented. In the following year the trial was repeated. Ewes from the previous year's trial (by then four-tooths) were augmented by a new cohort of pregnant two-tooths to make up numbers to 75. After lambing the lambs were divided into four groups: first by their dams' vitamin B₁₂ treatment, then half of each group received injections of vitamin B₁₂ at approximately three weekly intervals while the other half remained untreated. The trials lasted about five months, from mid-pregnancy until weaning. Pasture Co was at its lowest at lambing in both years, 0.09 and 0.10µg/g DM, respectively. In the first year, vitamin B₁₂ concentrations in the untreated ewes rose from 340 to 950 pmol/l in plasma and decreased in liver from 330 to 170 nmol/kg fresh tissue. In the Co treated group, vitamin B₁₂ concentrations in plasma rose from 500 to 1550 pmol/l and in liver from 310 to 560 nmol/kg fresh tissue. In the second year, vitamin B₁₂ concentrations in serum in the unsupplemented groups fell from 500 to 260 pmol/l around lambing before rising again to starting values at weaning, and liver vitamin B₁₂ concentrations fell from 450 at the start to 230 nmol/kg fresh tissue at the end of the trial. Serum vitamin B₁₂ concentrations in the two-tooth supplemented group rose from < 500 to > 3000 pmol/l whereas in the four-tooth supplemented group serum vitamin B₁₂ levels started at ~2800 and rose to nearly 5000 pmol/l. The supplemented four-tooths maintained higher liver vitamin B₁₂ concentrations throughout compared to the supplemented two-tooths, viz 680 compared to below 400 at the start and 900 versus 650 nmol/kg fresh tissue at weaning, respectively. MMA in the untreated groups rose to 15 and to 8 µmol/l during early lactation in the first and second years, respectively, whereas MMA in the treated groups stayed below 3 µmol/l in the first season and below 1.5 µmol/l in the second season. There was a live weight response to treatment in the ewes as the unsupplemented groups showed a significantly lower weight gain during the trials than the supplemented groups, viz 10.0 versus 13.6 kg in the first year, and 10.6 versus 13.3 kg in the four-tooths and 9.9 versus 12.1 kg in the two-tooths in the second year. There was also a significant difference in faecal egg count (FEC) in the first year. FEC in the untreated group was higher during lactation than in the treated group, viz 590 versus 170 eggs per gram wet faeces (epg), respectively. In the second year, the two-tooths had a higher FEC than the four-tooths, viz 120 versus 40 epg during the same time span, respectively. While there was a trend for treatment having an effect on FEC similar to that in the first year it was not significant. Supplementation of ewes in the first year increased mean milk vitamin B₁₂ concentrations at lambing from 800 to 1400 pmol/l and at weaning from 1750 to 4000 pmol/l. In the second year, Co bullet treatment increased milk vitamin B₁₂ concentrations in the four-tooths and two-tooths from 1500 and 2300 to 4000 and 2900 pmol/l at lambing, and from 1800 and 1400 to 6200 and 4500 pmol/l at weaning, respectively. Treatment of ewes increased vitamin B₁₂ concentrations in the lambs which were not themselves supplemented. Plasma values in the first year increased from 160 to 325 pmol/l soon after birth and from 650 to 900 pmol/l at weaning, and liver values from 75 to 140 nmol/kg fresh tissue soon after birth and from 150 to 240 nmol/kg fresh tissue at weaning. In the second year, plasma vitamin B₁₂ concentrations increased from 160 to 380 pmol/l soon after birth and from 500 to 700 pmol/l at weaning, and in liver from 130 to 260 nmol/kg fresh tissue soon after birth and from 220 to 340 nmol/kg fresh tissue at weaning. There was also a significant effect of ewe supplementation on lamb MMA in 1997/1998 when values decreased from 19 to 8 µmol/l around the time of rumen development. MMA in the second year stayed below 3 µmol/l throughout in all groups of lambs. There was no difference in LWG between any groups of lambs. FEC was lowest in the group where both ewes and lambs were supplemented and highest in the group where neither ewes nor lambs were treated. Further investigations were conducted on farms in Southland with lambs post-weaning in order to compare changes in serum and liver vitamin B₁₂ with serum MMA and LWG to determine the critical time and level of deficiency. In the first year, three farms with 50 lambs each participated. Lambs from each farm were allocated to five groups of 10 animals each. The first group received a Co bullet at weaning, and each month another group was treated with a Co bullet. The lambs were weighed monthly, and blood and liver samples were taken prior to treatment and each subsequent month from five lambs of the first supplemented group. The trial lasted about four months. Serum vitamin B₁₂ concentrations in lambs at weaning were between 500 and 1000 pmol/l. Although supplementation increased serum levels for the first month this was followed by a drop to near or below starting concentrations. An exception was Farm 3 where serum vitamin B₁₂ concentrations rose again at the end of the trial. Liver vitamin B₁₂ concentrations also showed an overall decline from starting levels (200 to 300 nmol/kg fresh tissue) to the end of the trial (100 to 200 nmol/kg fresh tissue). MMA started around 2 µmol/l and reached between 6 and 7 µmol/l in the untreated lambs on Farms 1 and 3 two months after weaning before decreasing to around 3 µmol/l at the end of the trial, whereas the treated lambs maintained MMA concentrations around 2 µmol/l. On Farm 2 MMA started just below 5 µmol/l, decreased to around 1 µmol/l for treated and untreated lambs one month later and rose again to between 2.5 and 4 µmol/l, respectively, at the end of the trial. LWG was below average for all lambs (between 0.20 and 0.04 kg/d except for Farm I in the first month after weaning) but no significant differences were noted between treated and untreated lambs on any of the farms. Another trial was conducted on one of these farms in the following year. One hundred lambs were divided into two groups of 50 each at weaning and sampled monthly for about six months. One group was treated with two Co bullets, the other group remained untreated. Pasture Co was between 0.04 and 0.07 µg/g DM, yet serum levels for the untreated group stayed ~500 pmol/l throughout the trial. Serum vitamin B₁₂ concentrations for the treated group started at ~500 pmol/l, rose to ~2500 pmol/l before falling back to ~2000 pmol/l. Liver vitamin B₁₂ concentrations for the untreated and treated groups were 529 and 427 nmol/kg fresh tissue at weaning, respectively. This decreased for both groups to ~350 nmol/kg fresh tissue one month after weaning. In the untreated lambs liver values decreased further to ~290 nmol/kg fresh tissue whereas they increased to ~450 nmol/kg fresh tissue for the treated group at the end of the trial. MMA concentrations started between 2 and 3 µmol/l for both groups and increased to 4.5 µmol/l for the untreated group one month later before falling back to 3.2 µmol/l. In the treated group MMA decreased to ~1µmol/l and stayed at that level throughout the trial. There was no difference in weight gain. In order to obtain an understanding of the distribution of corrinoids in biological tissues a High Performance Liquid Chromatography method was developed. The sensitivity of the analytical method meant that it was only practical to assay mainly liver samples because of the higher vitamin B₁₂ concentrations than in other tissues. The general finding was that the coenzyme 5’ –deoxyadenosylcobalamin (ado-cbl) constituted the highest proportion of corrinoids in liver (45 %), followed by analogues (28 %), OH-cbl (24 %) and lastly methy1cobalamin (3 %). Ado-cbl did tend to be proportionately higher in supplemented than in unsupplemented animals (56 and 42 %, respectively), whereas biologically non-active analogues tended to be higher in untreated than in treated sheep (29 and 21 %, respectively). It was concluded that in the farm trials Co deficiency was only mild or not present although deficiency would have been predicted from the low vitamin B₁₂ concentrations in serum and liver and from raised MMA values. Therefore, currently used thresholds in New Zealand appear to be too high for vitamin B₁₂, and overseas values for MMA do not seem to be appropriate. Revised marginal ranges of 100 to 200 pmol/l for serum, 100 to 200 nmol/kg fresh tissue for liver and 10 to 20 µmol/l for MMA are suggested. Further, this work shows that Co bullets were effective in elevating blood and liver vitamin B₁₂concentrations for longer than one year. In the trials with preruminant lambs it was found that maintenance requirements were met by the vitamin B₁₂ content of milk replacer. There is evidence from indoor and farm trials that vitamin B₁₂ from milk was much more readily absorbed than vitamin B₁₂ from supplements. It was estimated that suckling lambs probably require between 1200 and 4000 pmol vitamin B₁₂/d, depending on age.

Studies were conducted to determine the effects of feeding lasalocid and monensin upon mineral status of ruminants, changes in digestive and renal physiology which bring about altered mineral status, and the effects of dietary K upon the actions of ionophores. Two 84-d grazing trials were conducted with steers fed no ionophore, 200 mg lasalocid, or 150 mg monensin. Monensin tended to increase gain of steers, but lasalocid had no effect. Feeding supplemental lasalocid and monensin altered Ca, P, Mg, Na, K, Cu, Fe and Zn status of grazing steers, but effects were not consistent. Twenty-four crossbred steers were individually fed in a 147-d finishing trial to study a possible K x monensin interaction. Steers were fed diets ad libitum containing .4% or 2.3% K, with or without 23 ppm monensin, dry basis. Feeding monensin with low K increased serum Na, Mg, inorganic P, Cu and Zn, but monensin fed with high K had no effect or decreased these serum minerals. Fifteen wethers, fitted with abomasal and ileal cannulae, were fed a basal diet alone or supplemented with 23 ppm lasalocid or monensin; Apparent absorption of Mg, K and Fe increased when ionophores were fed. Magnesium flow through the small and large intestines was decreased by lasalocid and monensin. Effects of lasalocid and monensin differed for metabolism, digestive tract flow and (or) partial absorption of Ca, P, Cu, Fe and Zn. Twelve ewe lambs were used in a renal clearance experiment. Lambs were fed a basal diet with no ionophore, 23 ppm lasalocid, or 23 ppm monensin, dry basis. Ionophores were fed starting on d 1 of the experimental period. Serial collections of blood and urine were made during d 1 and d 5 of the experimental period. Monensin reduced urine flow rate at d 1 and d 5. Feeding monensin lowered serum clearance and urinary excretion rates of Na and K at d 5. Serum clearance and urinary excretion rates of Ca were lower in sheep fed ionophores at d 1. Feeding monensin decreased serum clearance and urinary excretion rates of Cu at d 1. At d 5, urinary excretion rates of Zn were greater when lasalocid was fed, and lower when monensin was fed, compared to feeding no ionophore. These studies indicate that dietary lasalocid and monensin can alter mineral status of ruminants, although their effects may differ. The effects of ionophores may be dependent upon dietary K levels.
Ph. D.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A ovinocultura é uma atividade em crescimento no plano pecuário brasileiro e é desenvolvida de maneiras diversas (extensiva, semi intensiva, intensiva). Nas criações, tem sido observada a incidência de urolitíase. Devido a este fato, o estudo de aspectos relacionados à gênese, prevenção, diagnóstico e tratamento torna-se necessário e atual. Incorporada ao aparecimento da urolitíase, a alimentação é um dos fatores predisponentes mais importantes na formação dos cálculos, principalmente em animais em confinamento recebendo dietas com maior volume de concentrados e pouca fibra. Este projeto tem como objetivo avaliar a influência da alimentação na constituição da urolitíase em ovinos. De modo específico, foram testadas dois tipos de dietas, as quais diferenciaram-se proporção cálcio/fósforo (Ca/P). O efeito da alimentação sobre os animais foi avaliado através de exames laboratoriais (ureia e creatinina séricas, urinálise, concentração de fósforo, magnésio e cálcio no sangue e na urina) e confirmação do diagnóstico por sinais clínicos. Foram utilizados 30 ovinos machos, com peso entre 18 e 20Kg e 4 meses de idade, divididos aleatoriamente em 2 grupos de acordo com a dieta: Grupo 1 (n = 15) - nível de fósforo de 0,43% e Grupo 2 (n = 15) - nível de fósforo de 0,65%. Os animais receberam as dietas por 90 dias consecutivos e água ad libitum. Momentos (M) de colheita de material: M0 - imediatamente antes do início da dieta e em intervalos de 15 dias nos momentos M1, M2, M3, M4, M5, M6. Foram colhidas amostras de urina e sangue para urinálise, dosagem sérica de ureia e creatinina e concentração de fósforo, Magnésio e Cálcio. Os animais com sinais clínicos urolitíase foram avaliados pelo exame físico, quando confirmado o diagnóstico, submetidos a tratamento clínico (hidropropulsão retrógrada uretral) e, quando necessária, uretrostomia
The sheep industry is a growing activity in the Brazilian livestock and plan is developed in different ways (extensive, semi-intensive, intensive). In creations, the incidence of urolithiasis has been observed. Due to this fact, the study of aspects related to the genesis, prevention, diagnosis and treatment becomes necessary and current. Incorporated to the onset of urolithiasis, power is one of the most important predisposing factors in stone formation, particularly in feedlot animals fed diets with higher volume of concentrates and little fiber. This project aims to evaluate the influence of power in the constitution of urolithiasis in sheep. Specifically, two types of diets, which differed ratio calcium/phosphorus (Ca/P) were tested. The effect of feeding on the animals was assessed by laboratory tests (serum urea and creatinine, urinalysis, concentration of phosphorus, magnesium and calcium in the blood and urine) and confirmation of diagnosis by clinical signs. 30 male sheep were used, weighing between 18 and 20kg and 4 months of age were randomly divided into 2 groups according to diet: Group 1 (n=15) - phosphorus level of 0.43% and Group 2 (n=15) - phosphorus level of 0.65%. The animals were fed the diets for 90 consecutive days and water ad libitum. Moment (M) of crop material M0 - immediately before the beginning of treatment and at 15 days intervals at M1, M2, M3, M4, M5, M6. Blood and urine samples for urinalysis, serum urea and creatinine and phosphorus concentration, Magnesium and Calcium were harvested. Animals with clinical signs urolithiasis were evaluated by physical examination, when confirmed the diagnosis, undergoing medical treatment (retrograde urethral hydropropulsion) and, when necessary, urethrostomy
FAPESP: 12/22620-8

Orientador: Roberto Calderon Gonçalves
Coorientador: Danilo Otávio Laurenti Ferreira
Banca: Simone Biagio Chiacchio
Banca: Ivan Roque de Barros Filho
Resumo: A ovinocultura é uma atividade em crescimento no plano pecuário brasileiro e é desenvolvida de maneiras diversas (extensiva, semi intensiva, intensiva). Nas criações, tem sido observada a incidência de urolitíase. Devido a este fato, o estudo de aspectos relacionados à gênese, prevenção, diagnóstico e tratamento torna-se necessário e atual. Incorporada ao aparecimento da urolitíase, a alimentação é um dos fatores predisponentes mais importantes na formação dos cálculos, principalmente em animais em confinamento recebendo dietas com maior volume de concentrados e pouca fibra. Este projeto tem como objetivo avaliar a influência da alimentação na constituição da urolitíase em ovinos. De modo específico, foram testadas dois tipos de dietas, as quais diferenciaram-se proporção cálcio/fósforo (Ca/P). O efeito da alimentação sobre os animais foi avaliado através de exames laboratoriais (ureia e creatinina séricas, urinálise, concentração de fósforo, magnésio e cálcio no sangue e na urina) e confirmação do diagnóstico por sinais clínicos. Foram utilizados 30 ovinos machos, com peso entre 18 e 20Kg e 4 meses de idade, divididos aleatoriamente em 2 grupos de acordo com a dieta: Grupo 1 (n = 15) - nível de fósforo de 0,43% e Grupo 2 (n = 15) - nível de fósforo de 0,65%. Os animais receberam as dietas por 90 dias consecutivos e água ad libitum. Momentos (M) de colheita de material: M0 - imediatamente antes do início da dieta e em intervalos de 15 dias nos momentos M1, M2, M3, M4, M5, M6. Foram colhidas amostras de urina e sangue para urinálise, dosagem sérica de ureia e creatinina e concentração de fósforo, Magnésio e Cálcio. Os animais com sinais clínicos urolitíase foram avaliados pelo exame físico, quando confirmado o diagnóstico, submetidos a tratamento clínico (hidropropulsão retrógrada uretral) e, quando necessária, uretrostomia
Abstract: The sheep industry is a growing activity in the Brazilian livestock and plan is developed in different ways (extensive, semi-intensive, intensive). In creations, the incidence of urolithiasis has been observed. Due to this fact, the study of aspects related to the genesis, prevention, diagnosis and treatment becomes necessary and current. Incorporated to the onset of urolithiasis, power is one of the most important predisposing factors in stone formation, particularly in feedlot animals fed diets with higher volume of concentrates and little fiber. This project aims to evaluate the influence of power in the constitution of urolithiasis in sheep. Specifically, two types of diets, which differed ratio calcium/phosphorus (Ca/P) were tested. The effect of feeding on the animals was assessed by laboratory tests (serum urea and creatinine, urinalysis, concentration of phosphorus, magnesium and calcium in the blood and urine) and confirmation of diagnosis by clinical signs. 30 male sheep were used, weighing between 18 and 20kg and 4 months of age were randomly divided into 2 groups according to diet: Group 1 (n=15) - phosphorus level of 0.43% and Group 2 (n=15) - phosphorus level of 0.65%. The animals were fed the diets for 90 consecutive days and water ad libitum. Moment (M) of crop material M0 - immediately before the beginning of treatment and at 15 days intervals at M1, M2, M3, M4, M5, M6. Blood and urine samples for urinalysis, serum urea and creatinine and phosphorus concentration, Magnesium and Calcium were harvested. Animals with clinical signs urolithiasis were evaluated by physical examination, when confirmed the diagnosis, undergoing medical treatment (retrograde urethral hydropropulsion) and, when necessary, urethrostomy
Doutor

CAPES; Fundação Araucária
Foi avaliado os efeitos da inclusão de gordura protegida na dieta em ovinos em relação ao consumo, digestibilidade, balanço de nitrogênio, pH ruminal, nitrogênio amoniacal (N-NH3) e açúcares totais (CHO). O experimento foi realizado na Unidade de Ensino e Pesquisa de Metabolismo Animal, da Universidade Tecnológica Federal do Paraná, Câmpus Dois Vizinhos, no período de julho a setembro de 2014. Teve duração de 90 dias, sendo 10 dias de adaptação ao ambiente, com 4 períodos experimentais de 20 dias, sendo 15 para adaptação a dieta e 5 dias para as coletas de fezes, sobras e urina, destes 5 dias, em 4 dias foram coletadas amostras do fluído ruminal. Foram utilizados 4 ovinos machos, sem raça definida, castrados e fistulados no rúmen com peso médio de 50±14kg, distribuídos em um delineamento experimental quadrado latino 4x4, onde os dados foram submetidos a análise de variância e regressão em função da inclusão da gordura. Os animais foram alimentados com concentrado á base de farelo de soja, farelo de trigo e milho com diferentes níveis de inclusão de gordura protegida, sendo o tratamento controle (sem adição de gordura protegida), e os outros três com níveis de inclusão de gordura protegida (2,0%, 4,0% e 6,0% da matéria seca) o volumoso utilizado foi o feno de Tífton 85. Os animais ficaram mantidos em gaiolas metabólicas, com alimento fornecido duas vezes ao dia, às 08:00 e às 16:00 horas. Não houve efeito da inclusão de gordura para consumo e digestibilidade da MS e dos nutrientes, exceto para o consumo de extrato etéreo com efeito linear positivo para (CEE = 22,80 +11,98x) e efeito linear positivo para o coeficiente de digestibilidade no extrato etéreo, sendo representado pela equação CDEE = 87,45+ 0,61x. Em relação ao pH ruminal, não houve efeito do tratamento em relação a adição de gordura, com valor médio de 6,03, porém houve em relação ao tempo, com efeito cúbico (P<0,05), no tratamento com adição de 2,0% de gordura protegida (pH= 6,07-0,02X- 0,01X²- 0,01X³). Sobre a concentração de N-NH3 observou-se efeito cúbico (P<0,05) dos níveis de inclusão de gordura (N- H3=10,50+0,79X + 0,11X² -0,02X³), e efeito cúbico em função do tempo, para o tratamento controle, com a equação N-NH3=9,07-0,08X-0,01X²- 0,01X³. Em relação à concentração de açúcares totais, observou-se efeito cúbico (P<0,05), em função do aumento dos níveis de gordura (CHO= 63,67-2,40X-0,43X²-0,07X³) e efeito quadrático (P<0,05) em função do tempo após a alimentação para o tratamento com adição de 2,0% de gordura protegida (CHO = 61,74 + 1,18X + 0,05X²). Recomenda-se inclusão de gordura protegida em até 6,0% nas dietas com alto teor de concentrado, pois mesmo com os efeitos observados, os valores finais das variáveis ficaram dentro do esperado, sem afetar o desenvolvimento dos animais .
It assessed the effects of inclusion of protected fat in the diet of sheep in relation to consumption, digestibility, nitrogen balance ruminal pH, ammonia (N-NH3) and total sugars (CHO). The experiment was conducted at the Unidade de Ensino e Pesquisa de Metabolismo Animal, da Universidade Tecnológica Federal do Paraná, Câmpus Dois Vizinhos, from July to September 2014. It lasted 90 days, with 10 days of adaptation to the environment, with four experimental periods of 20 days, 15 for adaptation to diet and 5 days for the collection of feces, urine and leftovers, these 5 days, 4 days of ruminal fluid samples were collected. 4 male sheep were used, mixed breed, neutered and rumen with an average weight of 50 ± 14 kg, distributed in a Latin square design 4x4, where the data were subjected to analysis of variance and regression due to the inclusion of fat. The animals were fed with concentrate based soybean meal, wheat bran and corn with different levels of inclusion of protected fat, with the control treatment (no addition of protected fat), and the other three with inclusion levels protected fat (2,0%, 4,0% and 6,0% of dry matter) the roughage used was Tifton 85 hay the animals were kept in metabolic cages, with food provided twice a day, at 08:00 and 16:00. No effect of the inclusion of fat intake and digestibility of MS and nutrients, except for the consumption of ether extract positive linear effect (CEE = 22,80 + 11,98x) and positive linear effect for the digestibility in ether extract, being represented by the equation CDEE = 87,45 + 0,61x. Regarding the ruminal pH, there was no effect of treatment with added fat, with an average value of 6,03, but was over time with a cubic effect (P<0,05) in treatment with addition of 2,0% protected fat (pH = 6,07-0,02X-0,01X² - 0,01X³). On the concentration of NNH3 cubic effect was observed (P<0,05) levels of inclusion of fat (N - NH3 = 10,50 + 0,79X + 0,11X² - 0,02X³) and cubic effect versus time for the control treatment with NNH3 = 9,07 - 0,08X - 0,01X² - 0,01X³ equation. Regarding the concentration of total sugars, there was a cubic effect (P<0,05), due to increased levels of fat (CHO = 63,67-2,40X-0,43X²- 0,07X³) and effect a quadratic (P<0,05) as a function of time after feeding for treatment with addition of 2,0% fat protected (CHO= 61,74+ 1,18X+ 0,05X²). It is recommended inclusion of fat protected by up to 6,0% in diets with high concentrate, because even with the observed effects, the final values of the variables were within the expected range, without affecting the development of animals.

Exposure of the fetus to adverse conditions in utero may result in developmental adaptations that alter metabolism and postnatal growth of the offspring. This thesis investigated the effects of dam size and nutrition during pregnancy on growth, metabolic function and lactational and productive performance of the female offspring to two years of age. Four-hundred and fifty heavy (60.8 kg ± 0.18) and 450 light (42.5 kg ± 0.17) dams were randomly allocated to ad libitum or maintenance nutritional regimens from days 21 - 140 of pregnancy, under pastoral grazing conditions. From one week prior to lambing, all dams were fed ad libitum until weaning. After weaning, female progeny were managed and fed under pastoral conditions as one group. Maternal nutrition during pregnancy affected lamb growth to weaning, however, after weaning lamb growth was affected by dam size. Dam size had no effect on glucose metabolism, adrenal function or fat metabolism in 16-month-old female twin offspring. Dam nutrition during pregnancy had a minor effect on glucose metabolism and no effect on adrenal function or lipolysis, however, it did possibly affect gluconeogenesis and/or glycogenolysis, with increased glucose production in ewes born to maintenance-fed dams. Ewes born to dams fed maintenance showed greater milk production, lactose percentage, lactose and crude protein yield. Ewes born to heavy dams showed greater milk production and lactose yield. Dam size had no effect on reproductive performance of the female offspring. Being born to a larger dam showed no advantages over being born to smaller dams, for number of lambs born and weight of lambs at birth and weaning. ‘Grand’dam maintenance nutrition increased lamb birth and weaning weight and lamb growth rates of the ‘grand’offspring. Ewes born to maintenance-fed dams could have an advantage over ewes born to ad libitum-fed dams in physiological stressful situations in life as their liver may be able to supply more glucose to support their growing conceptus and milk production to increase the chances of survival of their offspring. These results indicate that it is possible to programme the offspring by feeding their dams differently during pregnancy under grazing conditions. With a better understanding of how offspring can be programmed through different maternal nutritional regimens, it may be possible to significantly increase the production potential of the New Zealand ewe population.

The main hypothesis tested in this thesis was that poor animal production from saltbush pastures is due to the negative effects of high sodium chloride (NaCl) and potassium chloride (KCl) on the ruminal environment, and subsequent effects on microbial populations and products of rumen fermentation. This main hypothesis was tested in two experiments. In the first experiment (Chapter Four) the effects of saltbush and a formulated high-salt diet on the ruminal environment and microbial populations were measured over 24-hours following feeding. Feeding both the saltbush and high-salt diet increased the salinity of the rumen fluid, but the formulated high-salt diet caused a decrease in ruminal pH while the saltbush caused an increase. This resulted in differences in the composition of the ruminal microbial populations between the sheep fed different diets. In the second experiment (Chapter Five) the effects of saltbush and a formulated highsalt diet on rumen fermentation were measured. Sheep fed saltbush had inefficient rumen fermentation and this was only partially explained by the high salt content of the diet. Diets containing high levels of NaCl and KCl provided low levels of net energy to sheep, but sheep fed saltbush lost more energy as methane and faecal energy compared to sheep fed the formulated high-salt diet. Inefficient rumen fermentation could help to explain poor animal production from saltbush pastures. Energy supplements such as barley grain can improve the value of saltbush pastures as feed for sheep, but there is no information on how much supplement is required. A third experiment (Chapter Six) was designed to test the hypothesis that there would be an optimal amount of barley required to improve the efficiency of rumen fermentation in sheep fed saltbush. Barley and straw were combined in a pellet and substituted for saltbush at 0, 20, 40, 60, 80 and 100% of the maintenance ration. Feeding barley and straw improved the efficiency of rumen fermentation in sheep fed saltbush, with an optimal level of supplementation at 60% of the maintenance diet. This is likely to be lower (approximately 20% of maintenance) if barley is fed without straw.

Tradicionalmente no Rio Grande do Sul a ovinocultura mantinha um foco na produção de lã, onde os índices reprodutivos do rebanho possuíam pouca importância. Atualmente isso tem mudado devido à alta valorização do cordeiro no mercado. Nos sistemas com foco na produção de cordeiros os índices reprodutivos tornam-se chaves para a economicidade da propriedade. Mas, para que isso ocorra de uma maneira sustentável a eficiência reprodutiva dos rebanhos precisa alcançar melhores índices. O aumento na prolificidade através da manipulação da nutrição é um dos fatores que podem contribuir para melhorar esses índices, além de ser uma alternativa “limpa, verde e ética” de produção animal. Com isso, o objetivo deste trabalho foi de melhorar o desempenho reprodutivo de um rebanho de ovelhas Texel, submetidas a uma suplementação pré-encarneiramento. Foram utilizados 91 animais divididos em dois grupos, suplementado (n=46) e controle (n=45), de acordo com o peso e a condição corporal. As ovelhas do grupo experimental receberam um suplemento a base de milho e farelo de soja por sete dias prévios ao encarneiramento. As taxas de prenhez não diferiram entre os grupos (97,8% e 95,5%, respectivamente; P > 0,05) e observou-se uma tendência dos animais do grupo suplementado a conceberem em apenas um serviço (P=0,068). A prolificidade foi maior nas ovelhas suplementadas em comparação às ovelhas do grupo controle (P≤0,05), assim como nas ovelhas em melhor condição corporal que nas ovelhas em pior condição corporal (P≤0,05). Com isso, pode-se concluir que a suplementação pré-encarneiramento por sete dias com milho e farelo de soja aumentou o número de cordeiros nascidos do rebanho em 11%, além de diminuir o número de ovelhas com retorno ao primeiro serviço.
Traditionally in Rio Grande do Sul the sheep industry maintained a focus on wool production, in this systems the reproductive performance of the herd had little importance. Today, it has been changed due to the high value of the lamb in the market. The systems that have focus on the lamb production, reproductive performance become very important to the property´s economy. For this to occur in a sustainable manner, the reproductive efficiency of livestock must achieve better rates. The increase in prolificacy by manipulating nutrition is one of the factors that can contribute to improving these rates, and is an alternative "clean, green and ethical" in animal production. Thus, the objective was to improve the reproductive performance of Texel sheep, subjected to a pre-mating supplementation. In the experiment 91 animals were divided into two groups, control (n=45) and supplemented (n=46) according to their weight and body condition score. Ewes in the experimental group received a supplement based on corn and soybean meal for seven days prior to mating. Pregnancy rates did not differ between groups (97.8% and 95.5%, respectively, P> 0.05) and the group supplemented tended to conceive at the first service (P = 0.068). The prolificacy was higher in sheep supplemented compared to the control group (P≤ 0.05), as well as in ewes in better body condition than in ewes in poorer body condition score (P≤ 0.05). Thus, we can conclude that supplementation pre-mating for seven days with corn and soybean meal increased the number of lambs born by 11%, and reduce the number of ewes that return to first service.

CAPES
O experimento foi realizado na Universidade Tecnológica Federal do Paraná no período de abril a junho de 2015 tendo como objetivo avaliar o efeito da gordura protegida de óleo de palma na gestação e lactação de ovelhas e comportamento materno filial. Foram utilizadas 40 ovelhas mestiças Santa Inês e Dorper acasaladas com um carneiro da raça Dorper e 42 cordeiros. Foram fornecidos dois concentrados, com e sem gordura protegida de óleo de palma, os quais as ovelhas foram suplementadas a 1,0% do peso vivo corporal com base na matéria-seca. A cada 15 dias, foram realizadas pesagem e avaliação do estado de condição corporal das ovelhas, bem como ao parto. Nos cordeiros posterior ao parto avaliou-se o comportamento de forma direta, anotando-se registros de tempo que o cordeiro levou para ficar em pé e tempo decorrente do nascimento até a primeira mamada. O peso ao nascer foi aferido após a primeira mamada e a cada 15 dias, os cordeiros foram pesados, avaliados quanto o estado de condição corporal, período este avaliado do nascimento até o desmame, ou seja, o momento que o cordeiro atingiu 17 kg de peso vivo. A duração do anestro pós-desmame das ovelhas foi obtida através da manifestação do estro, detectada por macho vasectomizado, cuja região do esterno foi impregnada com mistura de pó xadrez e óleo vegetal. Essas observações foram realizadas desde o desmame até a manifestação do 1º estro. Não houve diferença entre os tratamentos, para peso vivo, escore de condição corporal e ganho médio diário. No entanto na fase de lactação observou-se diferença para ovelhas que receberam gordura protegida de óleo de palma na dieta, apresentando superioridade no aspecto de escore corporal das ovelhas comparadas as que não receberam gordura protegida. A variável que avaliou o tempo total do nascimento ao desmame demonstrou que ovelhas que receberam gordura protegida na dieta desmamaram seus cordeiros mais cedo e também tiveram um tempo menor de anestro pós desmame comparado às ovelhas que não receberam gordura protegida de óleo de palma na alimentação. A suplementação lipídica não influenciou nenhuma das variáveis relacionadas ao comportamento materno filial. Desta forma conclui-se que a utilização de gordura protegida de óleo de palma na lactação de ovelhas apresenta melhoras em parâmetros produtivos e reprodutivos.
The experiment was carried out at the Universidade Tecnológica Federal do Paraná, from April to June 2015, with the aim of evaluating the effect of the protected fat of palm oil on gestation and lactation of sheep and maternal filial behavior. Four hundred crossbred ewes Santa Inês and Dorper were mated with a Dorper lamb and 42 lambs. Two concentrates, with and without palm oil-protected fat were provided, and sheep were supplemented at 1.0% body weight based on dry matter. Every 15 days, weighed and evaluated the state of body condition of the sheep, as well as the delivery. In the post-partum ambs, the behavior was evaluated in a direct manner, recording the length of time the lamb took to stand and time from birth to the first feeding. The birth weight was measured after the first feeding and every 15 days, the lambs were weighed, evaluated for the body condition, which was evaluated from birth to weaning, that is, the moment the lamb reached 17 kg live weight. The duration of the anestrous post weaning of the sheep was obtained through the manifestation of estrus, detected by a vasectomized male, whose sternum region was impregnated with a mix of chess powder and vegetable oil. These observations were made from weaning to the manifestation of the 1st estrus. There was no difference between the treatments, for live weight, body condition score and average daily gain. However, in the lactation phase, a difference was observed for ewes who received protected fat from palm oil in the diet, presenting superiority in the aspect of sheep's body score compared to those who did not receive protected fat. The variable that assessed the total time of birth at weaning showed that sheep that received protected fat in the diet weaned their lambs earlier and also had a shorter time of anestrus after weaning compared to sheep that did not receive protected fat from palm oil in the diet. Lipid supplementation did not influence any of the variables related to maternal filial behavior. Therefore, it is concluded that the use of protected palm oil fat in sheep lactation presents improvements in productive and reproductive parameters.

[EN] The main objective of this Thesis was to study the energy metabolism in small ruminants under different nutrition sceneries. As methodology we utilized indirect calorimetry instead of direct calorimetry or feeding trials. Within indirect calorimetry we worked with a portable open circuit gas exchange system with a head hood. This open circuit respiration system permitted completed the whole energy balance and evaluate the efficiency of utilization of the energy of the diet for different physiological circumstances as milk production in dairy goats or maintenance in sheep. Besides, we could quantify in each trial some of the wastes related to environmental pollution as CH4 emissions and excretion of nitrogen in feces and urine. In this thesis three experiments were designed, two in dairy goats and other in sheep as we described below. In the first experiment, digestibility, energy balance, carbon and nitrogen balance, milk performance, rumen parameters and milk fatty acids and metabolites were obtained. Metabolic cages and open circuit indirect calorimetry system were the methods applied. Treatments consist in two mixed diets with alfalfa as forage. Within the concentrate, oat grain was replaced with rice bran. No significant differences were found for metabolizable energy intake (MEI), 1254kJ/kg of BW0.75 on average, and heat production (HP); 640 kJ/kg of BW0.75 on average. No differences were obtained for milk production (2.2 kg/d on average) and milk fat was greater in the rice bran diet (6.9% vs. 5.3% for rice bran and oat diets, respectively). Energy balance was positive and milk metabolites correlated these found. Regards to CH4 emissions, determined in vivo by gas exchange indirect calorimetry, goats fed the rice bran significantly reduced methane production (23.2 g/d vs 30.1 g/d). In the second experiment, we also used two types of diets, but in this case we substituted the forage and maintained the same concentrate; in one of the diets a grass (Maralfafa [Pennisetum sp.]- M diet) was used as forage and in the other an extensively used leguminous (Alfalfa [Medicago sativa]- A diet). Methods and analysis were the same that in Experiment 1, and here we include metabolites in urine and blood plasma. The dry matter intake was higher for diet A (1.8 vs 1.6 kg/d, respectively) and digestibility coefficients were higher for diet M. However, no significant differences were shown in MEI (1089 kJ/kg of BW0.75, on average) and HP (639 kJ/kg of BW0.75on average). Higher milk yield was observed in A diet than M diet (1.8 vs. 1.7 kg/d, respectively) and metabolites in urine, plasma and milk indicated better use of diet A than M, while no differences in milk composition were found (5% of fat and 4.3% of protein). Methane production was higher for A diet (28.5 g/d) than M diet (25.9 g/d), although these differences were not statistically significant. In the third experiment, energy partition was compared in two sheep breeds (Manchega vs. Guirra) fed above maintenance. We fed again with mixed diets and metabolic cages, indirect calorimetry, nitrogen balance and integral calculus were the tools used for these energy partitioning approach. An approximation of division of heat production was done. ME for maintenence was estimated at 354 kJ/kg of BW0.75and day, on average for the two breeds. Basal metabolic rate was different between breeds; 270 vs. 247 kJ/kg of BW0.75for Guirra and Manchega, respectively.
[ES] El objetivo principal de esta tesis fue estudiar el metabolismo energético en pequeños rumiantes bajo diferentes escenarios de nutrición. Como metodología se utilizó la calorimetría indirecta en vez de calorimetría directa o pruebas de alimentación. Dentro de la calorimetría indirecta trabajamos con un sistema portátil de circuito abierto de intercambio de gases con una "urna" (Heat hood). Este sistema de circuito abierto de respiración nos permitió completar todo el balance energético y evaluar la eficiencia de la utilización de la energía de la dieta para diferentes estados fisiológicos como producción de leche en cabras u oveja en mantenimiento. Además fue posible cuantificar en cada ensayo algunas perdidas relacionadas con la contaminación ambiental como emisiones de CH4 y la excreción de nitrógeno en heces y orina. En esta tesis se diseñaron tres experimentos, dos en cabras en lactación y otro en ovejas como describimos a continuación. En el primer experimento se han determinado, digestibilidad, balance energético, balance carbono nitrógeno, producción de leche, parámetros ruminales, ácidos grasos y metabolitos en leche. Jaulas metabólicas y un sistema de circuito abierto de calorimetría indirecta fue el método aplicado. Los tratamientos consistieron en dos dietas mixtas con alfalfa como forraje y dentro del concentrado el grano de avena fue reemplazado por cilindro de arroz. No se encontraron diferencias significativas en la energía metabolizable ingerida (MEI) de 1254 kJ/kg PV0.75 en promedio y una producción de calor (HP) de 640 kJ/kg PV0.75 en promedio. La producción de leche no presentó diferencias significativas entre las dos dietas, (2,2 kg/den promedio), la grasa de la leche fue mayor en la dieta de cilindro de arroz (6,9% vs. 5,3% para cilindro de arroz y avena respectivamente). El balance energético fue positivo y correlacionado a los metabolitos en leche determinados. En cuanto a las emisiones de CH4, determinadas en vivo mediante el intercambio de gases por calorimetría indirecta, las cabras alimentadas con el subproducto redujeron significativamente la producción de metano (23,2 g / d vs 30,1 g / d.). En el segundo experimento, también utilizamos dos tipos de dietas, pero en este caso sustituimos los forrajes y mantuvimos el mismo pienso; en una de las dietas se utilizó como forraje una gramínea (Maralfafa [Pennisetum sp.] - dieta M) y en el otro una leguminosa de uso extendido (Alfalfa [Medicago sativa] - dieta A). Los métodos de análisis y análisis fueron los mismos que los utilizados en el Experimento 1, y se incluyeron además análisis de metabolitos en orina y plasma. La materia seca ingerida fue mayor para dieta A (1,8 vs 1,6 kg/d, respectivamente), los coeficientes de digestibilidad fueron mayores para la dieta M. Sin embargo, no se encontraron diferencias significativas en MEI (1089 kJ/kg PV0.75, en promedio) y HP 639 kJ/kg PV0.75, en promedio). La producción de leche fue mayor en la dieta A que la dieta M, (1,8 vs. 1,7 kg/d, respectively) y los metabolitos en orina, plasma y leche indican un mejor aprovechamiento de la dieta A. No se presentaron diferencias en la composición de la leche (5% de grasa and 4.3% de proteína). La producción de metano fue mayor para la dieta A (28,5 g/d) que para la dieta M (25,9 g/d), aunque estas diferencias no fueron estadísticamente significativas. En el tercer experimento se compararon la partición energética en dos razas de ovejas (Manchega vs. Guirra) en mantenimiento. Fueron alimentadas con dietas mixtas en jaulas metabólicas, calorimetría indirecta, balance carbono nitrógeno y cálculos integrales fueron las herramientas utilizadas para un aproximación de la partición energética. Se realizó una aproximación de división de producción de calor. El ME para mantenimiento se estimó en 354 kJ/kg PV0.75/ día, en promedio para las dos razas. Las diferencias en la tasa metabólica basal entre las razas fu
[CAT] El principal objectiu d'aquesta tesi va ser estudiar el metabolism energètic en xicotets ruminants baix diferents escenaris de nutrició. Com a metodologia es va utilitzar la calorimetria indirecta en compte de calorimetria directa o proves d'alimentació. Dins de la calorimetria indirecta treballarem amb un sistema portatil de circuit obert d'intercanvi de gasos amb "urna" (Heat hood). Aquest sistema de respiració de circuit obert ens va permetre completar tot el balanç energètic i avaluar l'eficiència de la utilització de l'energia de la dieta per a diferents circumstàncies fisiològiques com produccion de llet en cabres o manteniment en ovelles. A més va ser possible quantificar en cada assaig algunes perdues relacionades amb la contaminacion ambiental com a emissions de CH4 i l'excreció de nitrogen en femta i orina. En aquesta tesi es van dissenyar tres experiments, dos en cabres en lactación i un altre en ovelles com vam descriure a continuació. En el primer experiment s'han determinat,digestibilidad, balanç energètic, balanç carboni nitrogen, producció de llet, paràmetres ruminales, àcids grassos i metabòlits en llet. Gàbies metabòliques i un sistema de circuit obert de calorimetria indirecta va ser el mètode aplicat. Els tractaments van consistir en dues dietes mixtes amb alfals com a farratge i dins del concentrat el gra de civada va ser reemplaçat per cilindre d'arròs. No es van trobar diferències significatives en l'energia metabolizable ingerida (MEI) de 1254 kJ/kg PV0.75 en mitjana i una producció de calor (HP) de 640 kJ/kg PV0.75 en mitjana. La producció de llet no va presentar diferències significatives entre les dues dietes, (2.2 kg/donen mitjana), el greix de la llet va ser major en la dieta de cilindre d'arròs (6.9% vs. 5.3% per a cilindre d'arròs i civada respectivament). El balanç energètic va ser positiu i correlacionat als metabòlits en llet determinats. Quant a les emissions de CH4, determinades en viu mitjançant l'intercanvi de gasos per calorimetria indirecta, les cabres alimentades amb el subproducte van reduir significativament la producció de metà (23.2 g / d vs 30.1 g / d.).En el segon experiment, també utilitzem dos tipus de dietes, però en aquest cas substituïm els farratges i vam mantenir el mateix pinso; en una de les dietes es va utilitzar com a farratge una gramínea (Maralfafa [Pennisetum sp.] - dieta M) i en l'altre una **leguminosa d'ús estès (Alfals [Medicago sativa] - dieta A). Els mètodes d'anàlisis i anàlisis van ser els mateixos que els utilitzats en l'Experiment 1, i es van incloure a més anàlisi de metabòlits en orina i plasma. La matèria seca ingerida va ser major per a dieta A (1,8 vs 1,6 kg/d, respectivament), els coeficients de digestibilidad van ser majors per a la dieta M. No obstant açò no es van trobar diferències significatives en MEI (1089 kJ/kg PV0.75, en mitjana) i HP 639 kJ/kg PV0.75, en mitjana). La producció de llet va ser major en la dieta Al fet que la dieta M, (1,8 vs. 1,7 kg/d, respectively) i els metabòlits en orina, plasma i llet indiquen un millor aprofitament de la dieta A. No es van presentar diferències en la composició de la llet (5% de greix i 4.3% de proteïna). La producció de metà va ser major per a la dieta A (28,5 g/d) que per a la dieta M (25,9 g/d), encara que aquestes diferències no van anar estadísticament significatives. En el tercer experiment es van comparar la partició energètica en dues races d'ovelles (Manxega vs. Guirra) en manteniment. Van ser alimentades amb dietes mixtes en gàbies metabòliques, calorimetria indirecta, balanç carboni nitrogen i càlculs integrals van ser les eines utilitzades per a un aproximació de la partició energètica. Es va realitzar una aproximació de divisió de producció de calor. L'EM para manteniment es va estimar en 354 kJ/kg PV0.75 / dia, en mitjana per a les dues races. Les diferències en la taxa metabòlica basal entre les races va ser de 2
Criscioni Ferreira, PF. (2016). Application of an open circuit indirect calorimetry system for gaseous exchange measurements in small ruminant nutrition [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64069
TESIS

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This study aimed to evaluate the intake, digestibility, performance, carcass characteristics, meat quality and components not constituents carcass of sheep fed increasing levels (0, 100, 200 and 300 g/kg of the diet DM) of annatto byproduct. We used 32 male sheep with an initial weight of 23.17 ± 1.45 kg. The animals were housed in individual stalls and feed offered twice daily. The nutrient intake was quantified by the fractional difference between the present and offered the leftovers. The apparent digestibility was measured using external marker LIPE®. The weight gain was measured by the difference between the final weight and the initial weight of the animals. Elapsed 58, fed, animals were slaughtered and the weights of body components registered. The morphometric measurements were performed in the cold carcass, which was later split into six anatomical regions. The leg was dissected and tissues quantified. In the left loin measurements were taken in color, water holding capacity, cooking loss and shear force. The organ, viscera and slaughter by-products were quantified and had their weights recorded. The dry matter intake (g/day;% PV; g/kg0, 75), organic matter (g/day), protein (g/day), neutral detergent fiber (g/day) was not affected (P > 0.05) by the inclusion of annatto byproduct. The total digestible nutrients showed an average of 0.794 g/day and was not affected (P>0.05) by the inclusion of byproduct of annatto. The apparent digestibility of dry matter, organic matter, crude protein and ether extract were not affected (P>0.05) by the inclusion of byproduct of annatto. The weight gain was not affected by the inclusion of annatto byproduct, but feed conversion and feed efficiency were affected. There was a linear effect (P<0.05) negative for hot carcass weight (kg) and cold carcass weight (kg). Increasing levels of annatto byproduct of a linear reduction (P<0.05) for the palette weight (kg) and leg (kg), but did not affect (P>0.05) yields of retail cuts. Adding the product of annatto decreased carcass compactness index (kg/cm) and the quantity of leg muscle (P<0.05). The weight of the leg reconstituted total weight of muscles, weight and weight of the biceps semitendinosus linearly negative (P<0.05) with the inclusion of the U.S. in the diet. There was no effect of the inclusion of SU (P>0.05) on the leg tissue composition (%), muscle: bone ratio, relative fat or muscle muscularity leg. The physico-chemical parameters of meat (color, shear force, water holding capacity and cooking losses) were not affected by the inclusion of the U.S. in the diet. Adding the product of annatto increased linearly (P<0.05) liver weight, the total weight of the organs in the body weight and the total weight slaughter organs due to the empty body weight. There was no effect (P>0.05) for inclusion annatto byproduct on the weight of the viscera, but the weight of the skin showed a linear negative (P<0.05). Income from “buchada” and “panelada” linearly positive (P<0.05) with the inclusion of annatto byproduct. The annatto byproduct can be included in the diet at levels up to 200 g/kg of total dry matter without affecting the intake, digestibility, weight gain, carcass characteristics of sheep.
Objetivou-se avaliar o consumo, digestibilidade, desempenho, características de carcaça, qualidade de carne e componentes não constituintes da carcaça de ovinos alimentados com níveis crescentes (0, 100, 200 e 300 g/kg da MS da dieta) do subproduto de urucum. Foram utilizados 32 ovinos machos, não castrados, com peso inicial de 23,17 ± 1,45 kg. Os animais forma alojados em baias individuais e a ração ofertada duas vezes ao dia. O consumo de nutrientes foi quantificado por diferença entre as frações presentes no ofertado e nas sobras. A digestibilidade aparente foi determinada com auxílio do marcador externo LIPE®. O ganho em peso foi obtido pela diferença entre o peso final e peso inicial dos animais. Decorrido 58 dias de confinamento, os animais foram abatidos e tiveram os pesos dos constituintes corporais registrados. As medidas morfométricas foram realizadas na carcaça fria, que, posteriormente, foi seccionada em seis regiões anatômicas. A perna foi dissecada e os tecidos quantificados. No lombo esquerdo foram ealizadas as medidas de cor, capacidade de retenção de água, perdas por cocção e força de cisalhamento. Os órgãos, vísceras e subprodutos do abate foram quantificados e tiveram seus pesos registrados. O consumo de matéria seca (g/dia; %PV; g/kg0,75), matéria orgânica (g/dia) e proteína bruta (g/dia) não foi influenciado (P>0,05) pela inclusão do subproduto do urucum. Os coeficientes de digestibilidade aparente da matéria seca, matéria orgânica, proteína bruta e extrato etéreo não foram influenciados (P>0,05) pela inclusão do subproduto do urucum. A taxa de ganho em peso não foi influenciado pela inclusão do subproduto de urucum, todavia, a conversão alimentar e eficiência alimentar foram influenciadas. Houve efeito linear (P<0,05) decrescente para o peso da carcaça quente (kg) e peso da carcaça fria (kg). Os níveis crescentes de subproduto de urucum proporcionaram redução linear (P<0,05) para o peso da paleta (kg) e da perna (kg), mas não influenciou (P>0,05) os rendimentos dos cortes comerciais. A inclusão do subproduto do urucum diminuiu o índice de compacidade das carcaças (kg/cm) e a quantidade de músculo na perna (P<0,05). O peso da perna reconstituída, peso total de músculos, peso do bíceps e peso do semitendinoso apresentaram comportamento linear negativo (P<0,05) com a inclusão do SU na dieta. Não houve efeito da inclusão do SU (P>0,05) sobre a composição tecidual da perna (%), relação músculo:osso, relação músculo gordura ou índice de musculosidade da perna. Os parâmetros físico-químicos da carne (cor, força de cisalhamento, capacidade de retenção de água e perdas por cocção) não foram influenciados pela inclusão do SU na dieta. A inclusão do subproduto do urucum aumentou linearmente (P<0,05) o peso do fígado, o peso total dos órgãos em função do peso corporal ao abate e o peso total dos órgãos em função do peso do corpo vazio. Não houve efeito (P>0,05) da inclusão do subproduto do urucum sobre o peso das vísceras, todavia, o peso da pele apresentou comportamento linear negativo (P<0,05). Os rendimentos de panelada apresentaram comportamento linear positivo (P<0,05) com a inclusão do subproduto do urucum. O subproduto do urucum pode ser incluído na dieta em níveis de até 200 g/kg da matéria seca total, sem afetar o consumo, a digestibilidade, a taxa de ganho de peso, características de carcaça e componentes não constituintes da carcaça de ovinos.

Thesis (MScAgric)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: The following study is to determine if a creep feed balanced for limiting essential amino acids (EAA) at a certain non structural carbohydrate (NSC) level will elicit greater responses than lambs reared on a commercial creep feed. Lysine, Threonine, Methionine, Isoleucine, Phenylalanine and Leucine were determined as the limiting amino acids for nursing lambs. These amino acids were incorporated into the creep feed treatments CF1 and CF2 representing 157 g CP/kg, 477 g NSC/kg and 179 g CP/kg, 508 g NSC/kg, respectively. A commercial creep feed with no optimisation for EAA is represented as CFC with 139 g CP/kg and 455 g NSC/kg. A negative control (CON) treatment represents lambs receiving no creep feed but with ad libitum access to suckle their dams while feeding on kikuyu pasture. A growth trial was conducted on Merino x Döhne-Merino cross twin lambs averaging a birth weight of 4.42 kg ± 0.11 for 60 days following with a digestibility trial towards the end of the trial. Half of the lamb crop was slaughtered at an average live weight of 23.6 kg ± 0.56. The M. longissimus dorsi was removed on both the left and right half of the carcass between the 2nd - 3rd last thoracic vertebrae and the 4th - 5th lumbar vertebrae. A sample from the rumen wall was taken at the rumino-reticular fold to determine development characteristics. Results indicate that the feed conversion ratio for the CFC lambs were better than CF1 (P = 0.052) but not more than CF2 (P = 0.307). The FCR was 0.88, 1.19 and 1.01 (kilogram feed required to gain 1 kg in bodyweight) for CFC, CF1 and CF2, respectively. Dressing percentage was higher for CF2 than for both CFC (P = 0.012) and CF1 (P = 0.077). Along with BUN data it was concluded that the high CP level of CF2 resulted in the higher fat deposition. The optimised creep feeds had higher nitrogen and energy balances than the commercial CFC, this implicates that the optimised creep feeds were more efficiently utilised. Optimised creep feed treatments had longer papillae than CON (P < 0.0001). Papillae of creep feed 2 was longer than CFC (P = 0.0537). Papillae width decreased as the NSC level increased thus it is surmised that higher NSC levels resulted in longer but thinner papillae. Rumen muscularization was equally developed between all the treatments and was ascribed to the lambs’ access to course roughage. Meat quality in terms of physical and chemical characteristics was found to be in range with that expected for lambs at higher slaughter weights (40 kg). In conclusion, the balancing of the limiting EAA increases the benefits of creep feeding while simultaneously being more efficiently utilised. Intensive sheep production systems may benefit from the feeding of such creep feeds provided it fits economically into their farming system.
AFRIKAANSE OPSOMMING: Die volgende studie is om te bepaal of 'n kruipvoer wat gebalanseerd is vir beperkende essensiële aminosure (EAA) by 'n vasgestelde nie-strukturele koolhidraat (NSK) vlak verbeterde groei sal ontlok teenoor lammers wat grootgemaak word op 'n kommersiële kruipvoer. Lisien, Treonien, Metionien, Isoleusien, Fenylalanien en Leusien is bepaal as die beperkende aminosure vir suipende lammers. Hierdie aminosure is opgeneem in die geoptimiseerde kruipvoer behandelings CF1 en CF2 wat 157 g RP/kg, 477 g NSK/kg en 179 g RP/kg, 508 g NSK/kg onderskeidelik verteenwoordig. 'n Kommersiële kruipvoer met geen optimalisering vir EAA is verteenwoordig as CFC met 139 g RP/kg en 455 g NSK/kg. 'n Negatiewe kontrole (CON) behandeling is verteenwoordig deur lammers wat geen kruipvoer ontvang het nie, maar wat ad libitum toegang tot hul ooi gehad het om te soog terwyl die ooi op ‘n kikoejoeveld wei. 'n Groei proef is uitgevoer met Merino x Döhne-Merino kruis tweelinglammers met ‘n gemiddelde geboorte gewig van 4,42 ± 0,11 kg vir 60 dae en 'n verteerbaarheids proef is na aan die einde van die studie uitgevoer. Helfte van die lam kudde is geslag by die lewende gewig van 23,6 ± 0, 56 kg. Die M. longissimus dorsi was op beide die linker-en regter helfte van die karkas tussen die 2de - 3de laaste torakale werwels en die 4de - 5de lumbale werwels verwyder. 'n Monster van die rumen wand is geneem langs die rumino retikulêre vou sodat die rumen ontwikkeling eienskappe daarmee bepaal kon word. Resultate dui daarop aan dat die voeromsetverhouding (VOV) vir CFC lammers beter was as vir CF1 (P = 0,052), maar nie meer as vir CF2 (P = 0,307) nie. Die VOV was 0,88 , 1,19 en 1,01 (kilogram voer wat nodig is om 1 kg liggaamsmassa aan te sit) vir CFC, CF1 en CF2 onderskeidelik. Uitslag persentasie vir CF2 was hoër as beide CFC (P = 0,012) en CF1 (P = 0,077). Saam met die bloed, urea en stikstofbalans data is daar tot die gevolgtrekking gekom dat die hoë RP inhoud van CF2 gelei het tot ‘n hoër vetneerlegging. Die geoptimaliseerde kruipvoere het ‘n hoër stikstof- en energiebalans gehad teenoor die kommersiële CFC behandeling wat dus impliseer dat die optimale kruipvoere doeltreffender benut was. Die geoptimaliseerde kruipvoer behandelings het langer papillae gehad as CON (P < 0,0001). Papillae lengte van die CF2 behandeling is langer as die van CFC (P = 0,0537). Papillae breedte het dunner geraak soos wat die NSK-vlak gestyg het dus word vermoed dat hoër NSK-vlakke langer maar dunner papillae tot gevolg het. Rumen bespiering is ewe ontwikkeld tussen al die behandelings en word toegeskryf aan die lammers se toegang tot growwe ruvoer. Vleis kwaliteit in terme van fisiese- en chemiese eienskappe was inlyn met wat verwag kan word vir lammers by hoër slaggewigte (40 kg). Ten slotte, die balansering van beperkende aminosure verhoog die voordele van kruipvoeding en word terselfdertyd doeltreffender benut. Intensiewe skaap produksie stelsels kan dus voordeel trek uit die voeding van sodanige kruipvoere mits dit ekonomies pas in die boerdery stelsel.

Thesis (MScAgric)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: The Dorper is numerically the second most abundent of all the sheep breeds in South Africa. It is the most numerous sheep breed in the dry arid areas of South Africa which make out a very big portion of the natural grazing in South Africa. In this study the feedlot performance was specifically investigated since so little research has been done in this regard. In the first study (Chapter 1), the production efficiency, body components and commercial yield of 13 Dorper and 12 Merino lambs were investigated. A pelleted diet was fed ad lib and the water intake per day was measured. Lambs were slaughtered at 30kg and at 40kg live weight and cut up according to the South African commercial cuts. The weights of the organs, head, feet, skin and carcass were also recorded. Results from the first study showed that Dorpers had a lower (P<0.05) water efficiency (285.97 mVkgO75/day) than the Merinos (240.07 mVkg075/day), but had a higher (P<0.05) nitrogen retention. The head, feet, skin, heart, lungs, kidneys and diaphragm of Merino lambs were heavier (P<0.05). Merinos had heavier (P<0.05) breast and shank and thick rib (only at 40kg live weight) cuts. But the Dorper had a significantly heavier hindquarter (buttock and loin) which is the high-priced cut of any carcass. It seems that the Dorper will do well under feedlot conditions, and would possibly make a better commercial meat producer than the Merino under all circumstances. In the second study (Chapter 2), the free-ranging Dorper on natural grazing were compared with 7 Dorper lambs in the feedlot study. The essential amino acids in the duodenal contents were compared. The free-ranging Dorpers were randomly slaughtered at 40 kg live weight and a duodenal sample was collected. The feedlot Dorpers were also slaughtered at 40 kg live weight and a duodenal sample was taken. The second study indicated no significant differences between the EAA composition of the duodenal samples, whether protein quantity was taken into account (gAA/100g crude protein (CP)) or not (expressed as % of lysine). The chemical scores indicated that the two most limiting amino acids in the duodenal digesta for whole empty body growth were: arginine and histidine. Excess levels of amino acids tend to be present in all three duodenal digesta samples (isoleucine, leucine, lusine, methionine, phenylalaline, threonine and valine). The whole empty body EAA composition (g AA/100 g crude protein) was as follows 7.10 arginine; 2.40 histidine; 3.31 isoleucine; 7.22 leucine; 6.61 lysine; 1.62 methionine; 3.91 phenylalanine; 3.77 threonine and 4.85 valine. The composition can serve as an example of the ideal EAA requirements for whole empty body growth between 30 and 40 kg live weight of Dorper ram lambs. The duodenal amino acid concentrations of the free-ranging Dorper compared well with those of the feedlot Dorpers which suggests that the microbial organisms have a big influence on the amino acid concentration which reaches the intestines.
AFRIKAANSE OPSOMMING: Die voerkraal prestasie en essentiele aminosuur behoeftes van groeiende Dorper lammers: The Dorper is getalgewys die tweede mees talryke skaapras in Suid-Afrika. Dit is die mees talryke skaapras wat in die drce woestynagtige gebiede van Suid-Afrika aangetref word. Die gebiede beslaan die grootste oppervlakte van Suid-Afrika se natuurlike weiveld. In die studie is voerkraal prestasie van die Dorper nagevors, spesifiek omdat daar so min navorsing op hierdie gebied gedoen is. In die eerste studie (Hoofstuk 1) is die produksie doeltreffendheid, liggaams komponente en kornrnersiele produksie van 13 Dorper- en 12 Merino lammers ondersoek. 'n Verpilde rantsoen is ad lib gevoer en die water inname per dag is ook gekontroleer. Die lammers is geslag op 30 en 40 kg lewende gewig en die karkasse is daarna opgesny volgens die Suid-Afrikaanse kornmersiele karkassnitte. Die resultate van die eerste studie het getoon dat Dorpers 'n laer water potentiaal (P<0.05) (285 97 mflkgO 75/dag) as die Merinos (240.07 mVkg075/dag) het. Dorper lammers het ook 'n hoer (P<0.05) stikstof retensie. Die kop, vel, pote, hart, longe, niere en diafragma van Merino lammers was swaarder (P<0.05). Merinos se brisket en dikrib snitte weeg ook swaarder (P<0.05). Die Dorper het 'n beduidende swaarder agterkwart (len de en boud) gehad, wat die duurste snit is van enige karkas. Die Dorper het baie goed gedoen in die voerkraal toestande en sal waarskynlik onder aile omstandighede 'n hcer vleisproduksie op die Merino lewer. In die tweede studie (Hoofstuk 2), is die vryweiende Dopers op natuurlike weiding vergelyk met die Dorpers in 'n voerkraal. Die twee groepe Dorpers se essensiele aminosuur samestelling in hul dunderms is bepaal en vergelyk om te bepaal of daar enige tekorte teenwoordig is. Die Dorpers in die veld en in die voerkraal is op 40 kg lewende gewig geslag en monsters van die dunderm inhoud is gekollekteer. Die monsters is ontleed om te bepaal of daar enige betekenisvolle verskille in die essensiele aminosure van die dunderm inhoud tussen die veld Dorpers en voerkraal Dorpers was. Die tweede studie het geen betekenisvolle verskille getoon tussen die dunderm monsters se essensiele aminosure, of die hoeveelheid proteien (gAA/100g) in aanmerking geneem is of nie (uitgedruk as % lisien). Die chemiese telling dui aan dat die twee mees beperkende aminosure in die dunderm inhoud vir lee liggaam groei arginien en histidien was. Oormaat vlakke van aminosure kom voor in al drie dunderm inhoud monsters (isoleusien, leusien, lisien, metionien, femielalanien, treonien en valien). Die totale lee liggaam essensiele aminosuursamestelling (g aminosuur/100g ruprotein) was soos volg: 7.10 arginien; 2.40 histidien; 3.31 isoleusien; 7.22 leusien; 6.61 lisien; 1.62 metionien; 3.91 fenielalanien; 3.77 treonien en 4.85 valien. Hierdie aminosuursamestelling kan as 'n aanduiding dien vir die ideale aminosuurbehoeftes van Dorper ram lammers vir totale lee liggaamsgroei vanaf 30 tot 40 kg lewende massa. Die dunderm aminosuur konsentrasie van die Dorper in die veld stem goed ooreen met die van die voerkraal Dorper. Dit toon waarskynlik dat die mikrobe organismes in die rumen In groot invloed het op die aminosuur samestelling wat die dunderm bereik.

Clinical diagnosis of vitamin B12/cobalt (Co) deficiency is difficult due to the unspecific nature of the clinical symptoms. The apparent increase in vitamin B12 deficiency in New Zealand in the late 1990’s made it clear that health providers were very reliant on plasma reference ranges to diagnose deficiency. However, the lack of quantitative data of what these reference ranges represent in terms of supply of vitamin B12, has prevented a better understanding of the metabolism of vitamin B12 within sheep. This thesis describes the development of an experimental approach to measure vitamin B12 production and absorption in sheep. The model was then used to investigate whether the type of carbohydrate source affects vitamin B12 production and/or absorption. In the first trial (Chapter 4), an adaptation of the repletion technique of Suttle (1974) for copper was used. Previously vitamin B12 depleted sheep were maintained on a diet of 400 g DM meadow hay and 250 g DM crushed barley and which provided a daily intake of 0.03 mg Co. Sheep were intravenously infused with known quantities of vitamin B12 (0 – 200 nmol hydroxycobalamin/d) to determine whether a relationship exists between plasma vitamin B12 concentration and rate of entry of the vitamin into the bloodstream and to quantify the relationship. Eight ewes fitted with rumen and abomasal cannulae were used in a paired 4x4 Latin square design. Four levels of vitamin B12 were infused into the jugular vein for 4 d followed by recovery period of 17 d and the plasma responses measured during this period. Control animals maintained relatively stable plasma levels while levels in treated animals rose sharply within 4 h after the start of infusion. The responses were proportional to infusion rate with a highly significant difference in concentrations observed between treatments (P<0.001). Appearance of vitamin B12 in the plasma was quantified by the relationship Y(pmol/l) = 238 + 102x0.74 where x = infusion rate(nmol B12/d), R² = 0.945. Plasma levels declined rapidly on cessation of infusion and had returned to original pre-treatment levels by the end of the recovery period. The second trial (Chapter 5) quantified plasma responses in relation to dietary Co supply to the rumen. The same eight rumen and abomasal cannulated ewes were used in a paired 4x4 Latin square with 4 levels of intra-ruminal Co infusion in amounts ranging from 0 – 1 mg Co/d as CoSO₄, infused for 4 d followed by a 19 d recovery period. Plasma vitamin B12 response was measured as were concentration of vitamin B12 in abomasal digesta supernatant and digesta liquid flow, the latter using polyethylene glycol as liquid phase marker. Plasma concentration increased from approximately 300 pmol/l to 750 – 800 pmol/l, peaking at day 5 after commencement of infusions. Control animals infused with water maintained base-line plasma vitamin B12 levels around 250 pmol/l. Digesta liquid flow was estimated at 14.6 l/d. The results from Chapters 4 and 5 allowed estimates of vitamin B12 production and absorption. These results are discussed and efficiency of capture of Co into vitamin B12 from dietary Co intake was estimated to decrease from 8.4% to 0.74% as Co intake increased from 0.03 to 1.11 mg Co/d. Absorption coefficient was estimated from the relationships between abomasal vitamin B12 flow and plasma response. The absorption coefficient was calculated to increase from 7 to 10% as abomasal vitamin B12 flow increased from 108 to 142 nmol/d. The current animal model was subsequently used in the final trial (Chapter 6) to investigate whether the type of carbohydrate supplied in the diet influences vitamin B12 production and absorption. The same eight ewes fitted with rumen and abomasal cannulae were used in a 2x4 cross-over design. Half of the ewes were maintained on the basal diet and crushed barley while, for the remainder, the barley was replaced by 250 g of fructose:sucrose in a 80:20 mix during a 7 d period of adaptation. While on their respective diets, both groups were then infused with 0.3 mg Co/d for 6 d, a level chosen to optimise plasma vitamin B12 response. All ewes were then returned to the basal diet and barley for a 15 d recovery period after which treatments were reversed and the procedure repeated. Rumen pH, valeric, propionic, butyric, succinic, and acetic acid and ammonia concentrations were not significantly affected by diet. Digesta flow was 30% greater on a diet enriched with starch compared to sugar-enriched diet. There was an observed difference in vitamin B12 production. However there was no significant diet x time effect on plasma vitamin B12 concentration so any difference in production was negated by a difference in absorption. Carbohydrate supplied as water soluble carbohydrate or starch does not appear to influence plasma vitamin B12 concentration.

The experiment was conducted from August 2011 to May 2012 in the Sheep Sector, Federal University of Sergipe. Aimed to study the effects of the transition period on dry matter intake, milk production, body condition score, body weight and metabolic profile, characterizing the transition period in Santa Ines sheep. We used 10 ewes, nullíparas, pregnant. The animals were confined to 30 days before expected farrowing until 60 days after delivery. To study the variables CMS, CMS (% BW), weight, BCS and metabolic profile were analyzed in three periods: Period 1: animals of 21 days pre-partum until delivery; Period 2: animals calving until 21 days postchildbirth; Period 3: animals over 21 days postpartum. Variables related to milk production (kg milk / day, kg corrected milk at 3.5% fat / day, fat percentage and fat yield in kg) were divided into two periods: PL30 (birth to 30 days); PL60 days (30-60 days postpartum). There were significant differences (P <0.05) in CMS and CMS (% PV) between the periods studied, with higher consumption in period 3, with a mean of 1.58 ± 0.07 kg and 2.83 ± 0.16% , respectively. Body weight and BCS showed significant differences (P <0.05) in period 1, with average 55.28 ± 1.12 and 3.34 ± 0.06 respectively. The results of the production and milk composition (PL, PLC, Gkg, G%) were similar between periods of lactation (P <0.05), with maximum efficiency in PL30. There was no significant difference (P> 0.05) variables of the metabolic profile (glucose, total protein, urea, albumin, triglycerides and AGNE). The transition period in Santa Inês ewes was featured 21 days pre partum and 21 days postpartum.
O experimento foi realizado no período de agosto de 2011 a maio de 2012 no Setor de Ovinocultura da Universidade Federal de Sergipe. Objetivou-se estudar os efeitos do período de transição sobre o consumo de matéria seca, produção de leite, escore de condição corporal, peso corporal e perfil metabólico, caracterizando o período de transição em ovelhas Santa Inês. Foram utilizadas 10 fêmeas ovinas, nullíparas, gestantes. Os animais foram confinados 30 dias antes do parto previsto até 60 dias após o parto. Para o estudo das variáveis CMS, CMS (% PV), peso, ECC e perfil metabólico foram analisados em três períodos: Período 1: animais dos 21 dias pré-parto até o parto; Período 2: animais do parto até 21 dias pós-parto; Período 3: animais acima de 21 dias pós-parto. As variáveis relacionadas à produção de leite (kg de leite / dia, kg de leite corrigido a 3,5% de gordura / dia, porcentagem de gordura e produção de gordura em kg) foram divididos em dois períodos: PL30 (do parto até 30 dias); PL60 dias (de 30 a 60 dias após o parto). Houve diferença significativa (P<0,05) no CMS e CMS (% PV) entre os períodos estudados, apresentando maior consumo no período 3, com média de 1,58 ± 0,07 kg e 2,83 ± 0,16 %, respectivamente. O peso corporal e ECC apresentaram diferença significativa (P<0,05) no período 1, com médias 55,28 ± 1,12 e 3,34 ± 0,06 respectivamente. Os resultados à produção e composição do leite (PL, PLC, Gkg, G%) apresentaram diferença entre os períodos de lactação (P<0,05), com máxima eficiência no PL30. Não houve diferença significativa (P>0,05) as variáveis do perfil metabólico (glicose, proteína total, uréia, albumina, triglicerídeo e AGNE). O período de transição em ovelhas Santa Inês foi caracterizado 21 dias pré parto e 21 dias pós parto.

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The sheep production in Brazil was always marginal to production of cattle, being the heritage of our colonization. However in recent years the rearing of sheep have been leveraged by demand for lamb meat. So has fetched the production of quality meat, from young animals. To achieve this quality level the intensification of rearing systems with the feedlot finishing is required. However the feedlot finishing is more costly than conventional finishing systems, being necessary to seek food and food additives that bring greater feed efficiency in the system. The purpose of this study was to evaluate the inclusion of amylolytic enzyme (ENZ), protected lysine (LIS), lysophospholipid (LYP) and protected methionine (MET) in a high concentrate diet control (CON) with ground corn meal and cottonseed meal to lambs. We sought to evaluate the ponderal performance at feedlot, quantitative characteristics of the carcass at slaughter, in vitro degradability of dry matter (DIVMS) of the diets and cumulative gas production in vitro. Were used 80 male lambs, not castrated with 20,57 ± 4,33 kg live weight (PV), crossbred Dorper x Santa Ines, being 60 slaughtered at the end of the experiment to evaluate the quantitative characteristics of the carcass. The animals were confined in 20 pens with four lambs each for a period of 64 days and treated twice daily at 7 a.m. and at 5 p.m. In the DIVMS the samples were incubated for 0, 3, 6, 12, 24 and 48 hours at 39°C under anaerobic conditions. Was calculated the degradability of dry matter (MS), estimating the parameters for the construction of degradability curves. The in vitro gas production was determined in the incubation times of 3, 6, 9, 12, 16, 24, 32, 48 and 72 hours, and compared the use of bovine and ovine ruminal fluid. There was no change in the quantitative characteristics of carcass how weight at slaughter (PA), hot carcass weight (PCQ), cold carcass weight (PCF), hot carcass yield (RCQ), cold carcass yield (RCF) and chilling loss (PPR) as result of the use of additives. There was a high correlation of PA with PCQ and PCF. However negative correlations were observed of the PA with RCQ, RCF and PPR, with lower correlation coefficients. Better performances were achieved with feedlot lambs feeding diets with the addition of ENZ and LYP, in the finishing phase. The inclusion of LYP increased DIVMS of diet, and MET decreases this variable. The gas production was greater in sheep inoculum until 48 hours of fermentation, there was no difference in time of 72 hours. The addition of ENZ increased the gases production only until 24 hours of fermentation, but after this period none of the additives tested increased the gases production.
A produção de ovinos no Brasil foi sempre marginal a produção de bovinos, sendo herança da nossa colonização. No entanto nos últimos anos a criação de ovinos tem sido alavancada pela demanda de carne de cordeiro. Assim se tem buscado a produção de carne de qualidade, proveniente de animais jovens. Para se alcançar este patamar de qualidade a intensificação dos sistemas de criação com a terminação em confinamento se faz necessária. Contudo a terminação em confinamento é mais onerosa do que a terminação em sistemas convencionais, sendo necessário que se busque alimentos e aditivos alimentares que tragam maior eficiência alimentar ao sistema. Objetivou-se neste trabalho avaliar a inclusão de enzima amilolítica (ENZ), lisina protegida (LIS), lisofosfolipídeo (LYP) e metionina protegida (MET) em uma dieta de alto concentrado (CON) com milho grão moído e torta de algodão para cordeiros. Buscou-se avaliar o desempenho ponderal no confinamento, características quantitativas da carcaça no abate, degradabilidade in vitro da matéria seca (DIVMS) das dietas e produção cumulativa de gases in vitro. Foram utilizados 80 cordeiros machos, não castrados, com 20,57 ± 4,33 kg de peso vivo (PV) mestiços Dorper x Santa Inês, sendo que 60 foram abatidos ao final do experimento para se avaliar as características quantitativas da carcaça. Os animais foram confinados em 20 baias coletivas com quatro cordeiros cada, por um período de 64 dias, sendo tratados duas vezes ao dia as 7 h e 17 h. Na DIVMS as amostras foram incubadas por 0, 3, 6, 12, 24 e 48 horas a 39°C, em meio anaeróbio. Foi efetuado o cálculo da degradabilidade da matéria seca (MS), estimando os parâmetros para a construção das curvas de degradabilidade. A produção de gases in vitro foi determinada nos tempos de incubação de 3, 6, 9, 12, 16, 24, 32, 48 e 72 horas, sendo comparado o uso de líquido ruminal bovino e ovino. Não foi observada nenhuma alteração nas características quantitativas da carcaça tais como peso de abate (PA), peso de carcaça quente (PCQ), peso de carcaça fria (PCF), rendimento de carcaça quente (RCQ), rendimento de carcaça fria (RCF) e perda pelo resfriamento (PPR) em consequência do uso dos aditivos. Observou-se alta correlação do PA com PCQ e PCF. No entanto correlações negativas foram observadas do PA com RCQ, RCF e PPR, com menores coeficientes de correlação. Melhores desempenhos ponderais podem ser alcançados com cordeiros confinados recebendo dietas com a adição de ENZ e LYP, na fase de terminação. A inclusão de LYP aumentou a DIVMS da dieta, sendo que MET diminui esta variável. A produção de gases foi maior em inóculo ovino até 48 horas de fermentação, não havendo diferença no tempo de 72 horas. A adição de ENZ incrementou a produção de gases somente até 24 horas de fermentação, mas após este período nenhum dos aditivos testados aumentou a produção de gases.

The Kahne rumen sensor (bolus) is a device developed to measure temperature, pressure and pH in non-fistulated animals. This bolus allows real-time monitoring of the rumen environment, which could help preventing health problems such as rumen acidosis in cows. It is less invasive to use boluses compared to other technologies that measure the ruminal pH (e.g. rumenocentesis). Kahne boluses and transceivers are commercially available in the market. Several studies on the relationships between data recorded by the bolus and actual data recorded by independent devices were conducted. The bolus temperature and pressure were compared with actual temperature and pressure under controlled conditions. The pH drift was studied by comparing the difference between bolus and direct measurement over time. The capture of the data was calculated for each bolus in various experiments to examine the factors affecting the data capture rate of the boluses. Animal to animal variation was studied using boluses in a group of cows fed and managed under uniform conditions. An animal experiment involving fistulated cows eating two different diets was performed using boluses to monitor the changes of ruminal pH. There was no apparent interruption to normal animal behaviour as a result of using boluses. Regression relationships between bolus measurements and actual data for both temperature and pressure were developed and used for calibration of bolus data. The pH drift was a problem, as the regression relation between the pH difference and the time for one bolus from one experiment could not represent this bolus on other experiment. The data capture rate on the hourly basis ranged from 0 to 100%, but was usually between 30 to 70%. The data capture rate was affected by many factors and further studies to identify these factors are needed. A study of animal to animal variation suggests that in a comparison of 2 treatments, a minimum 3 cows per group would be required to detect the standard deviation of 0.11 for a pH difference of 5% of the mean (approximately 0.35 pH units). Seventeen cows per group would be required to detect the standard deviation of 0.33 for the same difference. The boluses effectively monitored the ruminal pH change in cows easting two different diets and the profile of change of pH was successfully analysed. Feeding 7.6 kg baleage twice a day cause pH to decrease at 0.009 pH units per minute during feeding, while offering a similar quantity of grass and hay once a day resulted in a decrease of 0.0009 pH units per minute during feeding. The beginning of pH increase was about 1 hour following feeding and continuous during resting and rumination. The level of pH increase did not differ significantly for two diets.. The Kahne devices appear to have advantages compared to other technologies for the measurement of parameters of the rumen environment on a real-time basis. Boluses are especially good at intensively monitoring the temperature, pressure, and pH in the rumen. The major limitations of this technology to be used are the data capture rate and the pH drift. By improving the limitations found in the experiment, the Kahne rumen sensor could become very useful for both scientific research and under commercial conditions for monitoring animal health.

This thesis describes a series of four experiments designed to evaluate the role of the supply of protein in livestock grazing high quality pasture during mating and during pregnancy. The first two studies investigated the effects of high crude protein content of spring or autumn re-growth pasture on the reproductive performance of dairy cows and of ewes at mating. The last two studies investigated how the dietary supply of protein, body condition and their interactions contribute to the breakdown of immunity during the peri-parturient period in ewes and investigated underlying endocrine mechanisms. In the first study (Chapter 3) cows were blood sampled via the tail vein during the breeding period in spring. Plasma was then analysed for urea concentration. Cows with high plasma urea (HPU) or low plasma urea (LPU) were defined as those with plasma urea concentrations of ≥ or < 44.9 mg/dl respectively. Lactating cows (n = 200) were also categorized into high milk producers (HMP) or low milk producers (LPM) relative to an average daily yield of 26.6 l/d. Pasture clipping showed an average pasture CP (crude protein) content of 223 g/kg DM. Concentrations of plasma urea ranged from 26.6 to 64.4 mg/dl. No correlation was observed between plasma urea concentration and either reproductive indicators or milk parameters. Mean blood urea concentration of HPU cows was 50.8 compared to 38.5 mg/dl in LPU cows. There was a trend for more animals (P = 0.09) in the HPU group than in the LPU group not to return to oestrus. Cumulative pregnancy rate in HPU and LPU was similar except at week 6 after the start of mating when more (P < 0.01) HPU than LPU cows were pregnant. Calving to conception interval, calving interval and interval between conception and first service were similar (P > 0.05) between HPU and LPU cows. Gestation length, calving rate, milk yield and milk components were also similar (P > 0.05) between LPU and HPU cows. There was no difference (P > 0.05) in plasma urea concentrations between HMP and LMP milk producers. However, calving to conception interval, interval between calving and first service and calving interval were longer (P < 0.001), submission rate higher (P < 0.001) and NRR (Non-return rate) higher (P < 0.05) in LMP than HMP. The number of services, the interval between first and second service, gestation length and CR (calving rate) were similar (P > 0.05) between HMP and LMP cows. HMP had lower (P < 0.001) milk protein and fat concentrations than LMP cows. This information indicates that, despite the fact that plasma urea was consistently higher than levels in the literature which have been associated with reduced fertility in dairy cows; no impairment of reproductive performance was observed. In the second experiment (Chapter 4) mature and dry Coopworth ewes were blocked by weight, body condition and previous prolificacy (high, HP vs low twinning frequency, LP) into two groups and thereafter randomly allocated to diet which were designed to provided either 1) high protein (163 g/kg DM, ryegrass/red clover pasture, HPP) or low protein (119 g/kg DM, hay and barley grain, HB) supply at joining. These were designed to provide high and low plasma urea concentration. Over a period of 17 days, ewes recorded as mated were examined by laparoscopy, at which time there was no difference in blood urea concentration (58.6 vs 56.1 mg/dl) between HPP and HB groups. Fifty days after the start of joining the number of foetuses present was counted using ultrasonography. As a consequence of lack of difference in the plasma urea concentration, irrespective of treatment group, individual animals were categorized into high (HU) and low plasma urea (LU) status based on whether plasma urea concentration was higher or lower than the sample mean of 51.5 mg urea/dl. Lambs which weighed greater than the mean plus one standard deviation for their litter size were classified as oversize. Ovulation rate and conception rate were similar (P > 0.05) between HPP and BH and between HU and LU ewes. Ewes with previous high reproductive performance (HP) as would be expected had higher ovulation rate (P < 0.001) and conception rate (P < 0.01) than LP ewes. Embryo losses was not (P = 0.06) different between HB and HPP ewes. Urea category (HU vs LU) did not (P > 0.05) influence embryo mortality. Foetal loss, neonatal loss, total reproductive loss and mean lamb birth weight was were not affected by diet, nor urea category (P > 0.05). Single ovulations had tended (P = 0.08) to contribute to higher embryo loss compared to multiple ovulations, and, single foetuses suffered higher (P<0.001) losses compared to multiples. While the study did not achieve large differences in plasma urea concentrations between diets, the levels of plasma urea operating were high yet reproductive wastage rates were similar to those recorded in the literature. Together with similar apparent lack of effect on a high plasma urea environment, the data suggest either that previous findings from controlled studies have a more complex aetiology or that pastoral animals can adapt to high tissue ammonia/urea status. The third trial (Chapter 5) was designed to provide information on the supply of amino acids to the abomasum from protein supplementation which have previously been found to overcome dietary scarcity associated with limitation of peri-parturient increase in FEC. Twin-suckling ewes were fitted with rumen and abomasal cannulae and grazed a ryegrass/clover sward (C) or the same sward but with a 500 g/h/d protein supplement (S). The trial was designed as a cross-over with two 14 day adaptation periods followed by two five-day digesta-sampling periods. All ewes were treated with anthelmintic 14 days after lambing. Weekly analysis of blood glucose was carried on whole blood and analysis of amino acids in plasma. The flows of amino acids (AA) and dry matter (DM) at the abomasum were measured during both sampling periods using intra-ruminally infused markers. Live weight and faecal egg count (FEC) were recorded weekly. Diurnal variation in AA flow at the abomasum peaked between 12:00 and 15:00 h and was greatest in S ewes. Flows of AA, including DAPA, were increased by supplementation by 16%, while sulphur amino acids (SAA) were the most enhanced (by 21%) and flows of leucine, lysine, glutamine and aspartate were increased by about 20%. There were significant time effects in rumen and abomasal pH (P < 0.01; in both cases in both periods) reflecting increase in pH after 09.00 h. During Period II, rumen pH in digesta of C ewes was significantly higher (P < 0.001) than that of S ewes (6.7 ± 0.05 vs 6.4 ± 0.05 for C and S ewes, respectively). Plasma AA concentrations (P < 0.01) were lower in S ewes 21 days after parturition, but similar (P > 0.05) to those of C ewes at other times. Forty-three days after lambing (after cross over), the order was reversed as plasma methionine and cysteine concentrations of C ewes became low (P < 0.05). These changes in plasma AA were accompanied by changes in body condition score between day 23 and 70 post-partum whereby C ewes lost more body condition than S ewes. There was evidence for a lower FEC in S ewes, being 46 vs. 670 epg, respectively for S and C groups (P = 0.08) 21 days after anthelmintic treatment. There were higher (P < 0.05) blood glucose levels in C compared to S ewes at day +35 relative to lambing which was reversed and significantly higher (P < 0.01) for S ewes by day +56 from lambing (after treatments were reversed). There was no significant effect of treatment on live weight and lamb performance. There are limited data in amino acid supply on lactating ewes on pasture and the present study contributes additional information on the supply of amino acids at the abomasum. The prediction that flow rates that sulphur amino acids may have been enhanced to the greatest degree could be significant since sulphur amino acids are needed for the synthesis of glutathione for immune response. It can be calculated that supplementation to supply the quantities of S-amino acid at pasture would be needed, since it would not be possible for sheep to increase pasture intake to achieve similar S-amino acid flow. Increase in bypass amino acids in S ewes at certain times in the day probably suggests influence by protein supplementation at certain times of the grazing cycle. Reduced plasma free amino acids at day +21 relative to lambing, may indicate sparing of body protein breakdown by protein supplementation. However, the difference in blood glucose on day 35 and day 56 may indicate re-adjustment of hormonal settings, responsible for nutrient partitioning. The last study (Chapter 6) used ewes during the peri-parturient period on pasture. Eighty pregnant ewes were allocated into four groups balanced for anticipated number of lambs. Group 1 had a high body condition score (BCS) of 4.0 which was maintained throughout pregnancy by pasture allowance (HM; n = 20). Group 2 (n= 40) had medium body condition (BCS 3.0) and were split into two subgroups; one was offered pasture to allow gain of condition (MH; n = 20) and the second allowed to lose condition by offering a low grazing allowance (ML; n = 20). Group 3 were thin ewes (BCS 2.4) and pasture allowance was designed to maintain this condition (LM; n = 20). These feeding regimes were maintained for 3 weeks from week -8 of pregnancy. During week -5 to -4 all ewes were acclimatized to a protein supplement (60 g/d). A glucose tolerance test (GTT) was conducted during week -4 after which half of the ewes in each group were offered a protein supplement at the rate of 500 g/d, creating –S and –NS groups. During wk -2, a second GTT was carried out. Animals were treated with an anthelmintic 3 wks before lambing, and were then challenged with a dose of 10 000 Teladorsagia circumcincta larvae on weeks -2 and -1 relative to lambing. Weekly recording of FEC, live weight and body condition was carried out. Lambs were weighed within 24 h of birth and again at 44 and 65 d of age. Computed tomography body scanning was carried out on ewes at weeks -8, -3 and +8 relative to lambing. There were no differences (P > 0.05) in lamb performance due to body condition or protein supplementation. FEC of all groups was low (≈ 9 peg) and there was no (P > 0.05) significant difference between ewes of different body condition or due to effects of protein supplementation. Ewes bearing/bearing multiple lambs had the highest FEC at day -32 and +12 relative to lambing, which was significant (P < 0.05) on the latter date. There were no significant effects of supplementation on parasite status. There were differences in basal plasma glucose concentration between groups (P < 0.001), being highest in HM/S and least in ML/NS ewes and was generally higher (P <0.001) during GTT 2 than GTT 1. Ewes carrying a single foetus had higher (P <0.001) basal glucose than those carrying multiple lambs (2.2 vs. 1.7 mmol/L, respectively). Other plasma glucose response indexes were similar (P <0.05) between groups. There were differences in insulin responsiveness between groups (P < 0.001), being highest in MH/S and least in ML/S ewes. Insulin responsiveness tended (P = 0.06) to be lower during GTT 1 than GTT 2, but was higher (P < 0.01) in ewes carrying singles than multiples. There was tendency for higher though non-significant, basal insulin concentrations in HM ewes. Insulin trends over time after glucose infusion suggest greater insulin response at GTT 1. Basal insulin was not correlated with CT muscle weight. Despite differences in body muscle mass at the start of the trial and differences induced by nutrition during late pregnancy, positive gains in muscle mass occurred during early pregnancy and muscle mass was similar in all groups by day 56 of lactation. Animals with greatest fat content at parturition (HM) mobilised the greatest amount and those with least fat (LM) deposited fat during lactation. Further experimentation may consider the use of the hyperinsulinemic-euglycemic clamp approach to more precisely estimate whether hormonal re-setting through insulin resistance may be involved in relaxation of immunity during the peri-parturient period.