Letteratura scientifica selezionata sul tema "Ewes Feeding and feeds"

Feeding lowland sheep on straw-based systems during pregnancy (Davies and Chapple 1995) has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation was fed. Whole barley and soya bean meal has been the standard ration. Experiments with March-lambing ewes (Chapple et al., 1997) has shown that feeds based on molassed sugar beet feed and maize distillers dark grains can replace a barley/soya supplement. The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with higher levels of distillers grains to January-lambing ewes on straw-based and big-bale silage systems during pregnancy and early lactation.

The feeding of lowland sheep on straw-based systems during pregnancy was developed at ADAS Rosemaund during the last decade (Davies and Chappie 1995). Results showed that ewe and lamb performance were satisfactory, providing adequate compound supplementation was fed. Whole barley and soya bean meal has been the standard ration, but feeds based on high protein molassed sugar beet feed (Probeet Trident Feed) and maize distiller's dark grains could improve palatability and be easier to feed. The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds and maize distiller's dark grains to pregnant ewes on a straw-based feeding system.

The feeding of lowland sheep on straw-based systems during pregnancy was developed at ADAS Rosemaund during the last decade (Davies and Chappie 1995). Results showed that ewe and lamb performance were satisfactory, providing adequate compound supplementation was fed. Whole barley and soya bean meal has been the standard ration, but feeds based on high protein molassed sugar beet feed (Probeet Trident Feed) and maize distiller's dark grains could improve palatability and be easier to feed. The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds and maize distiller's dark grains to pregnant ewes on a straw-based feeding system.

The feeding of ewes in late pregnancy is critically important because this is a period of high foetal growth rate. Feed blocks have been used to replace compound feeds in both hill and upland flocks but there is limited information available on block-feeding to lowland flocks.To evaluate the replacement of trough-feeding with self-help feed blocks, for housed ewes fed good quality grass silage during late pregnancy, and to lactating ewes at grass.

The feeding of ewes in late pregnancy is critically important because this is a period of high foetal growth rate. Feed blocks have been used to replace compound feeds in both hill and upland flocks but there is limited information available on block-feeding to lowland flocks.To evaluate the replacement of trough-feeding with self-help feed blocks, for housed ewes fed good quality grass silage during late pregnancy, and to lactating ewes at grass.

Feeding of lowland sheep on straw-based systems during pregnancy and in early lactation has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation is fed (Davies and Chapple, 1995). Whole barley and soya bean meal has been the standard ration. However, soya bean meal is imported and not fully traceable. Experiments with January- and March-lambing ewes have shown that traceable, homeproduced feeds based on equal quantities of molassed sugar beet feed and either maize or barley distillers grains can replace a barley/soya supplement when fed with straw or silage-based diets in late pregnancy (Chappleet al., 1998 and 1999). The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with distillers grains to March-lambing ewes rearing twin lambs at pasture.

Feeding lowland sheep on straw-based systems during pregnancy is practised on many livestock/arable farms. Simple mixes of molassed sugar beet feed and distillers dark grains have been cost effective supplements for March-lambing ewes fed straw and produced satisfactory ewe and lamb performance (Chappleet al., 1998 and 2001). An ensiled mix of pressed sugar beet pulp and dried maize distillers grains (Praize, Trident Feeds) has been fed as the sole diet for finishing lambs (Pattinsonet al., 2001) but there is little information on feeding Praize to pregnant ewes. The objective of this study was to compare ewe and lamb performance when March-lambing ewes were fed on a straw-based system and supplemented with either a cereal/protein home-mix, Praize or one of two dried sugar beet pulp/protein mixes.

Feeding of lowland sheep on straw-based systems during pregnancy and in early lactation has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation is fed (Davies and Chapple, 1995). Whole barley and soya bean meal has been the standard ration. However, soya bean meal is imported and may not be fully traceable. Maize or barley distillers fed with beans could provide traceable protein to replace soya bean meal in sheep diets. Experiments with housed early-lambing ewes and ewes suckling twin lambs at grass have shown that traceable feeds, based on molassed sugar beet and either maize or barley distillers grains, can replace a barley/soya supplement when fed with straw based diets in late pregnancy or at grass (Chappleet al., 1999 and 2000). The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with distillers grains and beans to March-lambing ewes on a straw-based system.

An in situ study compared mature, frost-damaged safflower to full-bloom safflower and mid-bloom alfalfa-grass hay, with the full-bloom safflower and alfalfa-grass hay also used in a ewe (n = 40) feeding study. Feed refusals were higher (P < 0.05) for ewes fed the safflower, but feed conversion efficiency was improved (P < 0.05) for the safflower-fed sheep. Ewes were bred shortly after the 9-wk feeding trial and the proportion of ewes lambing was higher (P < 0.05) in the safflower-fed ewes. Sheep were able to utilise the safflower forage as thorough chewing of spines likely prevented mouth ulceration and the ewes selectively consumed the most nutrient-dense parts of the forage. Key words: Safflower forage, sheep, fertility

The monitoring of a high fecundity ewe flock in the Te Anau basin demonstrates the process of improved feeding to improve lamb survival and growth to weaning. Feed budgeting was changed from traditional to tailored feed requirements based on measured ewe liveweight with wastage of 15% factored in. Feed allocation was changed from monthly to weekly increases during late pregnancy, and set stocking was delayed until the planned start of lambing. This increased late pregnancy feed allocation from 99 kg DM/ewe to 128 and 144 kg DM/ewe for twin and triplet bearing ewes, respectively. Ewe body condition score was maintained at between 3 and 3.5, with condition score loss between scanning and lambing being reduced to zero. Lamb survival and lamb liveweight gain to weaning increased in both twin and triplet bearing ewes. Pregnancy scanning increased from 200 to 222 lambs per 100 ewes, between 2007 and 2012, while lambing percentage (lambs weaned/ ewe mated) rose from 132% to 165%, with more ewes rearing lambs and rearing multiples. Lamb wastage declined from 37% in 2007 and 2008, to 25% in 2011 and 2012, though scanning percentage rose by 20%. Lamb weights increased from 27.5 to 36 kg/lamb at 100 days of age. The increase in the liveweight of lambs and ewes at weaning reduced the calculated feed requirements over summer and autumn, potentially releasing 70 to 110 kg DM/ewe to provide feed to meet the extra winter feed requirements. Keywords: ewe body condition score, feed allocation, lamb survival, lamb weaning weight

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.

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

Assignment (MPhil)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The aim of this study was to evaluate the performance and profitability of different dietary specifications for broiler chickens slaughtered at 35 days of age. Two trials were performed to evaluate different production parameters. The results of these trials were compared to the predicted results of the EFG broiler model. No carcass data were available for the two trials mentioned above. Therefore, in order to evaluate the accuracy of the broiler model when predicting carcass characteristics, two published data sets (Leeson et al., 1996a) were used. Predicted and actual values were compared, evaluated and discussed. Two broiler trials were performed. In Trial One the amino acid density decreased throughout the range of three treatments from prestarter to finisher diets. In Trial Two the amino acid density decreased only in the four finisher diets. The main difference between predicted and actual results was the response to body weight. The model predicted a steady increase in feed intake to compensate for the lower dietary specifications while body weight did not change significantly. This increase in feed intake seems to be enough to maintain body weight. Trial birds also increased their feed intake as dietary amino acid density decreased, but this compensation seemed to be too low to maintain body weight compared to the control diet. The birds may find it easier to compensate when they have time to adapt to the specification. There is evidence in the literature that birds need seven days to adapt their feed intake to a lower feed specification (Leeson et al., 1996a). It can be speculated that the trial birds started to loose body weight due to a lower amino acid intake in this period. The model seems to adapt feed intake immediately after a change in diet specification. The simulation on literature data lead to the following conclusions: 1) Broilers posses the capacity to increase their feed intake with at least 65% should finisher diets with lower amino acid and energy concentrations be supplied. If only the energy concentration of finisher diets were decreased, the increase in feed intake will be around 30%. (see Table 16 and 23) 2) The accurate prediction of feed intake from the given dietary specification has a major influence on the accuracy of the prediction of broiler performance. 3) Amino acid density and DLys:ME ratio plays a significant role in the control and prediction of feed intake. The EFG broiler model is based on sound scientific principles. The model is comprehensive and can be used for a wide range of environmental and management conditions as well as dietary conditions. The nutritionist can use the model with confidence to assist in practical feed formulation. The actual strength of the model lies in the time and money being saved compared to practical trials.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om die prestasie en winsgewendheid van braaikuikens te bepaal wanneer voere met verskillende digthede tot op 35 dae gevoer word. Twee eksperimente is uitgevoer om produksieresultate te evalueer. Die resultate van hierdie eksperimente is met die voorspelde waardes uit die EFG simulasie-model vergelyk. Aangesien geen karkasdata vir bogenoemde eksperimente beskikbaar was nie, is twee gepubliseerde datastelle gebruik om hierdie deel van die model te evalueer (Leeson et al., 1996a). Twee braaikuiken eksperimente is uitgevoer. Eksperiment Een het uit drie behandelings bestaan waarvan die aminosuur-konsentrasie vanaf dag een tussen behandelings verskil het. In Eksperiment Twee het die aminosuur-konsentrasie net in die vier afrondingsdiëte verskil. Liggaamsmassa op 35 dae het die grooste verskil tussen voorspelde- en werklike waardes getoon. Beide voorspelde en werklike innames het in albei eksperimente verhoog soos wat aminosuur-konsentrasie afgeneem het. Voorspelde liggaamsmassa het egter konstant gebly terwyl werklike data 'n afname in liggaamsmassa getoon het. Dit bleik dat die voorspelde toename in innames voldoende was om massa te onderhou terwyl die voëls in werklikheid nie genoeg gekompenseer het nie. Leeson et al., 1996a het tot die gevolgtrekking gekom dat braaikuikens minstens sewe dae benodig om hul voeriname by 'n nuwe spesifikasie aan te pas. So 'n stadige aanpassing kan daartoe lei dat energie- en aminosuur-inname daal indien 'n dieet met laer spesifikasie gevoer. Dit sal daartoe lei dat die kuikens liggaamsmassa verloor. Uit die literatuur simulasies is die volgende afleidings gemaak: 1) Braaikuikens besit die vermoeë om voerinname in die afrondingstyd met minstens 65% te verhoog indien 'n afrondingvoer met laer amiosuur- asook energiekonsentrasie gevoer word. Indien net die energiekonsentrasie verlaag word, sal die inname met sowat 30% verhoog. 2) Die akkurate voorspelling van inname is krities vir die akkurate voorspelling van produksieparameters. 3) Aminosuur-digtheid en DLys:ME speel 'n belangrike rol in die beheer en voorspelling van voerinname by braaikuikens. Die EFG braaikuikenmodel is op suiwer wetenskaplike beginsels geskoei. Die model is omvattend en kan vir 'n wye reeks van omgewings- en bestuurstoestande asook dieet-spesifikasies gebruik word. Die voedingkundige kan die model met vertroue gebruik om met praktiese voerformulering by te staan. Die model kan die formuleerder baie tyd spaar aangesien praktiese eksperimente ingeperk kan word.

This research reports on the determination of the effects of fish size and feed pellet size on the settling characteristics of Rainbow trout (Salmo gairdneri) culture, tank cleaning wastes. Flocculant particle settling curves (Type II) were developed from settling column analysis of cleaning wastes from 11-311 gram Rainbow trout fed a moist pellet diet (Oregon Moist Pellet ®). Four feed pellet sizes were investigated: 3/32, 1/8, 5/32 and 3/16 inch. Overall non-filterable residue removal curves and individual particle settling velocity distribution curves, derived from the Type II settling curve of each fish size and feed pellet size group, were compared. Slopes and y-intercepts of the linearized overall non-filterable residue removal curves and individual particle settling velocity distribution curves were compared using the Equality of Slope Test (S:SLTEST). Results of the test for a common regression equation indicated there were no significant differences in the proportional distribution of particle sizes within the cleaning wastes. Variations observed in the initial rates of removal within the overall non-filterable residue removal curves were considered insignificant Settling trials were pooled in order to obtain single curves, characterizing the overall solids removal rate and the individual particle settling velocity distribution of the waste solids.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

Abstract This chapter discusses the nutrient requirements; feed formulation; feed composition of clovers, grasses, lucerne, concentrates, grains, feed supplements and feed additives; feed processing and feeding of rabbits.

Abstract In this chapter the feeding behaviour and digestive physiology, digestive tract function-intrinsic and microbial digestion; functions and anatomy of the digestive tract in animals are discussed.

Abstract This chapter explores the nutritional composition of insects and the potential benefits and drawbacks for their inclusion into pet, poultry, pig, ruminant and aquatic animal feeds. Six species are most commonly described for use in animal feed, namely black soldier fly (BSF; Hermetia illucens) larvae and prepupae, yellow mealworm (YM; Tenebrio molitor) larvae, superworm (SW; Zophobas morio) larvae, lesser mealworm (LM; Alphitobius diaperinus) larvae, house fly (HF; Musca domestica) larvae and house crickets (HC; Acheta domesticus). The nutritional composition, variability observed due to manipulation of feed source, age, developmental stage and suitability for inclusion into animal feed are compared.

Abstract This chapter describes how cropping systems can be used to supplement feeds to increase dairy and poultry yields. It completes the concept of on-farm integration of crop, livestock and natural resources technologies necessary for sustainable intensification on smallholder farms. The different processes that utilize different feed sources to produce better-quality feed rations for dairy cows and poultry are also discussed.

AbstractFish and feed waste provide most of the nutrients required by the plants in aquaponics if the optimum ratio between daily fish feed inputs and the plant growing area is sustained. Thus, the fish feed needs to fulfil both the fish’s and plant’s nutritional requirements in an aquaponic system. A controlled fish waste production strategy where the nitrogen, phosphorus and mineral contents of fish diets are manipulated and used provides a way of influencing the rates of accumulation of nutrients, thereby reducing the need for the additional supplementation of nutrients. To optimize the performance and cost-effectiveness of aquaponic production, fish diets and feeding schedules should be designed carefully to provide nutrients at the right level and time to complement fish, bacteria and plants. To achieve this, a species-specific tailor-made aquaponic feed may be optimized to suit the aquaponic system as a whole. The optimal point would be determined based on overall system performance parameters, including economic and environmental sustainability measures. This chapter thus focuses on fish diets and feed and reviews the state of the art in fish diets, ingredients and additives, as well as the nutritional/sustainable challenges that need to be considered when producing specific aquaponic feeds.

The article presents the data of domestic and foreign researchers for feeding of poultry used lupin and its processed products. It’s advisable to use energy-and-protein concentrates made of legumes and cereal grain mixtures to prepare complete feeds. Lupin is one of the main sources of plant protein with unique amino acid composition. In opinion of the majority of researchers lupin containing feeds made according to technic guidance support productivity increasing of poultry growing and improve the quality of the products.

Increasing or decreasing the sodium level relative to the control does not adversely affect the level of safety of the livestock and the appetite of the birds. At the same time, feeding quails with compound feeds with a sodium level of 0.4 and 0.6% reduces feed costs per unit of production.

Studies have been conducted on the use of surepny oilcake obtained from different varieties of Brassica rapa L., in the feeding of broiler chickens. The safe norms of its inclusion in the composition of balanced compound feeds have been determined. The enrichment of experimental compound feed with enzyme preparations increases the economic performance of broiler chickens. The oilcake surepny obtained from the seeds of the Brassica rapa L, selection of the All-Russion Williams Fodder Research Institute confirms the effectiveness of cultivation and the negative effect on broiler chickens.

The article presents an analysis of a comprehensive study of the growth and development indicators of rainbow trout grown on granulated feeds using a plankton microalgae suspension concentrate Chlorella vulgaris (GKO) as a bioadditive. The possibility of using the studied biopreparation in the feeding ration of trout as an active additive with an immunocorrecting effect has been proven. The use of a Chlorella suspension at a concentration of 10 ml / kg increases the survival and resistance of trout jewels, as well as the general strengthening of the immune background of the fish organism.

In the Federal Scientific Center "VIK im. V. R. Williams” conducted research on the evaluation of new varieties of spring and winter colza Zarya and Nadezhda when growing broiler chickens of the Cobb 500 cross. The control group received compound feed without rapeseed seeds. The first and second experimental groups included 7.5% by weight of mixed fodder native rapeseed seeds of Zarya and Nadezhda varieties, which were used to replace part of soybean meal and sunflower oil. The content of nutrients in mixed feed complied with the regulatory requirements. The oil was balanced in composition: a large amount of monounsaturated, low-saturated fatty acids, a moderate amount of polyunsaturated fatty acids. It has been established that compound feeds with rapeseed seeds do not negatively affect the live weight gain of experimental broiler chickens. On the 39th day, the live weight of chickens in the control, in the first and second experimental groups was 2.250, 2.245 and 2.256 g, respectively. The significance of the difference in this indicator with the control group has not been established (P > 0.05). In the study of blood serum in chickens of the first experimental group, an increased level of bilirubin and the enzyme glutamyltransferase was revealed, which indicates stagnation of bile in the bile ducts (P > 0.01). The efficiency of growing poultry using rapeseed seeds was higher than in the control, which is associated with a decrease in feed costs for obtaining meat products and a lower cost of experimental feed.

Experience feedback refers to the timely information collection, transformation, analysis, processing and summary, when some good experience or occasional problems appeared during the manufacturing process. In the manufacturing process of nuclear fuel, CNNC JianZhong Nuclear Fuel Assembly Co., Ltd (CJNF) established a comprehensive experience feedback system, and consolidated experience feedback processing flow. Using classification and gradation to collect, filter, organize and use information. CJNF feeds back some quality problems in fuel assembly manufacture, through the analysis of causes and the implementation of measures to avoid the occurrence of similar problems. Meantime, feeding back and sharing good practical experience in manufacturing and management process, it is benefit to pass on experience and learn from each other. The experience feedback of CJNF is the solid foundation of quality management system’s operation and improvement.

The fate of transgenic DNA (tDNA) and protein of feeds from Genetically Modified organisms (GMOs) in animals has been an important topic since their commercialization in 1996. Several studies have investigated about risks of horizontal gene transfer (HGT) of tDNA and proteins to bacteria or animal cells/tissues, however, the reported data is at times controversial. Earlier reports showed that tDNA fragments or protein derived from GM plants have not been detected in tissues, fluids, or edible products of farm animals. Other researchers have come out to demonstrate that there is the possibility of small fragments leaking out into the animal tissues, fluids and organs. This motivated us to update our knowledge about these concerns. Therefore, this review aimed at assessing the likely transfer and accumulation of tDNA/ proteins from transgenic feeds to animal (ruminants and non-ruminants) samples through evaluating the available experimental scientific published studies. This study has found out that the tDNA or protein is not completely degraded during feed processing and digestion in the Gastro-Intestinal Tract (GIT). In large ruminants (Cattle), tDNA fragments/protein have been detected in the GIT digesta, ruminal fluid and feces. In small ruminants (Goats), traces of tDNA/proteins have been detected in the GIT digesta, blood, milk, liver, kidney, heart and muscle. In pigs, they have been detected in blood, spleen, liver kidney and in the GIT digesta. In poultry, traces have been seen in blood, liver and GIT digesta but not in meat and Eggs. Regardless of some studies that have shown the transfer of tDNA/protein fragments to animal samples, we cannot base on these few studies to give a piece of general evidence about their transfer into tissues/fluids and organs of livestock animals. However, this study clearly shows possible transfer, hence intensive and authentic research on GM crops should be done before they are allowed for commercial use, studying issues like the fate of tDNA or proteins and the effect of feeding GM feeds to livestock.

The FAO has projected a doubling in world demand for seafood during the 21 ed from aquaculture of marine fish and shrimps fed primarily on fishmeal-based aquafeeds. However, current practices of high intensity monoculture of shrimp in coastal ponds and fish in offshore pens have been strongly criticized as being ecologically and socially unsustainable. This view derives from un- checked eutrophication of coastal marine ecosystems from fish farm effluents, and the destruction of coastal estuarine ecosystems by shrimp farm constructions, plus aquaculture’s reliance on wild-caught small fish - which are excellent food for humans, but instead are rendered into fishmeal and fish oil for formulating aquafeeds. Fishmeal-sparing and waste- reduction aquafeeds can only delay the time when fed aquaculture product are priced out of affordability for most consumers. Additionally, replacement of fishmeal protein and fish oil by terrestrial plant sources such as soybean meal and oil directly raises food costs for human communities in developing nations. New formulations incorporating sustainably-produced marine algal proteins and oils are growing in acceptance as viable and practical alternatives. This BARD collaborative research project investigated a sustainable water-sparing spray/drip culture method for producing high-protein marine macrophyte meals for incorporation into marine shrimp and fish diets. The spray culture work was conducted at laboratory-scale in the USA (UCSD-SIO) using selected Gracilariaand Ulvastrains isolated and supplied by UCONN, and outdoors at pilot-scale in Israel (IOLR-NCM) using local strains of Ulvasp., and nitrogen/phosphorus-enriched fish farm effluent to fertilize the spray cultures and produce seaweed biomass and meals containing up to 27% raw protein (dry weight content). Auburn University (USA) in consultation with TAMUS (USA) used the IOLR meals to formulate diets and conduct marine shrimp feeding trials, which resulted in mixed outcomes, indicating further work was needed to chemically identify and remove anti-nutritional elements present in the IOLR-produced seaweed meals.

Research objectives were: 1) To study the effect of diet energy density, level of exercise, thermal conditions and reproductive state on cardiovascular function as it relates to oxygen (O2) mobilization. 2) To validate the use of heart rate (HR) to predict energy expenditure (EE) of ruminants, by measuring and calculating the energy balance components at different productive and reproductive states. 3) To validate the use of HR to identify changes in the metabolizable energy (ME) and ME intake (MEI) of grazing ruminants. Background: The development of an effective method for the measurement of EE is essential for understanding the management of both grazing and confined feedlot animals. The use of HR as a method of estimating EE in free-ranging large ruminants has been limited by the availability of suitable field monitoring equipment and by the absence of empirical understanding of the relationship between cardiac function and metabolic rate. Recent developments in microelectronics provide a good opportunity to use small HR devices to monitor free-range animals. The estimation of O2 uptake (VO2) of animals from their HR has to be based upon a consistent relationship between HR and VO2. The question as to whether, or to what extent, feeding level, environmental conditions and reproductive state affect such a relationship is still unanswered. Studies on the basic physiology of O2 mobilization (in USA) and field and feedlot-based investigations (in Israel) covered a , variety of conditions in order to investigate the possibilities of using HR to estimate EE. In USA the physiological studies conducted using animals with implanted flow probes, show that: I) although stroke volume decreases during intense exercise, VO2 per one heart beat per kgBW0.75 (O2 Pulse, O2P) actually increases and measurement of EE by HR and constant O2P may underestimate VO2unless the slope of the regression relating to heart rate and VO2 is also determined, 2) alterations in VO2 associated with the level of feeding and the effects of feeding itself have no effect on O2P, 3) both pregnancy and lactation may increase blood volume, especially lactation; but they have no effect on O2P, 4) ambient temperature in the range of 15 to 25°C in the resting animal has no effect on O2P, and 5) severe heat stress, induced by exercise, elevates body temperature to a sufficient extent that 14% of cardiac output may be required to dissipate the heat generated by exercise rather than for O2 transport. However, this is an unusual situation and its affect on EE estimation in a freely grazing animal, especially when heart rate is monitored over several days, is minor. In Israel three experiments were carried out in the hot summer to define changes in O2P attributable to changes in the time of day or In the heat load. The animals used were lambs and young calves in the growing phase and highly yielding dairy cows. In the growing animals the time of day, or the heat load, affected HR and VO2, but had no effect on O2P. On the other hand, the O2P measured in lactating cows was affected by the heat load; this is similar to the finding in the USA study of sheep. Energy balance trials were conducted to compare MEI recovery by the retained energy (RE) and by EE as measured by HR and O2P. The trial hypothesis was that if HR reliably estimated EE, the MEI proportion to (EE+RE) would not be significantly different from 1.0. Beef cows along a year of their reproductive cycle and growing lambs were used. The MEI recoveries of both trials were not significantly different from 1.0, 1.062+0.026 and 0.957+0.024 respectively. The cows' reproductive state did not affect the O2P, which is similar to the finding in the USA study. Pasture ME content and animal variables such as HR, VO2, O2P and EE of cows on grazing and in confinement were measured throughout three years under twenty-nine combinations of herbage quality and cows' reproductive state. In twelve grazing states, individual faecal output (FO) was measured and MEI was calculated. Regression analyses of the EE and RE dependent on MEI were highly significant (P<0.001). The predicted values of EE at zero intake (78 kcal/kgBW0.75), were similar to those estimated by NRC (1984). The EE at maintenance condition of the grazing cows (EE=MEI, 125 kcal/kgBW0.75) which are in the range of 96.1 to 125.5 as presented by NRC (1996 pp 6-7) for beef cows. Average daily HR and EE were significantly increased by lactation, P<0.001 and P<0.02 respectively. Grazing ME significantly increased HR and EE, P<0.001 and P<0.00l respectively. In contradiction to the finding in confined ewes and cows, the O2P of the grazing cows was significantly affected by the combined treatments (P<0.00l ); this effect was significantly related to the diet ME (P<0.00l ) and consequently to the MEI (P<0.03). Grazing significantly increased O2P compared to confinement. So, when EE of grazing animals during a certain season of the year is estimated using the HR method, the O2P must be re measured whenever grazing ME changes. A high correlation (R2>0.96) of group average EE and of HR dependency on MEI was also found in confined cows, which were fed six different diets and in growing lambs on three diets. In conclusion, the studies conducted in USA and in Israel investigated in depth the physiological mechanisms of cardiovascular and O2 mobilization, and went on to investigate a wide variety of ruminant species, ages, reproductive states, diets ME, time of intake and time of day, and compared these variables under grazing and confinement conditions. From these combined studies we can conclude that EE can be determined from HR measurements during several days, multiplied by O2P measured over a short period of time (10-15 min). The study showed that RE could be determined during the growing phase without slaughtering. In the near future the development microelectronic devices will enable wide use of the HR method to determine EE and energy balance. It will open new scopes of physiological and agricultural research with minimizes strain on animals. The method also has a high potential as a tool for herd management.