Academic literature on the topic 'Pangola grass'

A widespread disease of pangola grass (Digitaria decumbens) and summer grass (D. ciliaris) in south-eastern Queensland was characterized by a bunched and stunted growth habit, yellow or red discolouration of the foliage, seed heads with crimped, distorted racemes, and sometimes premature plant death. Virus-like particles present in extracts of diseased plants were unstable, 50-70 nm in diameter, had a core and outer coat and were morphologically similar to particles of viruses in the genus Fijivirus, family Reoviridae. The particles were shown by immune electron microscopy to be serologically closely related to pangola stunt and maize rough dwarf viruses, but unrelated to oat sterile dwarf virus. Similar virus-like particles were observed in crystalline arrays in ultrathin sections of cells in vein enations of D. ciliaris. Extracts of diseased pangola grass and summer grass contained 10 double-stranded RNA species, which were somewhat similar in size to those reported for pangola stunt virus. A planthopper, Sogatella kolophon, which is related to the South American vector of pangola stunt virus, S. furcifera, was associated with diseased pangola grass and summer grass in the field, and was shown to be a vector. However, efforts to infect maize, a major host of maize rough dwarf virus, were unsuccessful. On the basis of these properties the Australian virus is considered to be pangola stunt virus.

1. In a number of experiments voluntary food intake of three low-quality roughages, either alone or supplemented with rumen-degradable nitrogen and sulphur and minerals, was measured in Brahman (Bos indicus) and Hereford (Bos taurus) steers. The chaffed hays were Spear grass (Heteropogon conform) (6.2 g N/kg organic matter (OM)), Pangola grass (Digitaria decumbens) (7.9 g N/kg OM), and Pangola grass (12.0 g N/kg OM). Rumen characteristics relating to rate of fluid outflow from the rumen were also determined.2. There was no significant difference between breeds in the dry-matter intakes of the unsupplemented diets which ranged from 11.3 to 17.8 g/kg body-weight (BW) by Herefords and from 11.8 to 16.1 g/kg BW by Brahmans.3. Supplementation of Spear grass with N and S significantly (P < 0.05) increased intake by Herefords (24%) but not by Brahmans. When the lower-N Pangola grass was supplemented there was a significant increase in intake by both breeds with the magnitude of the response in Herefords (42%) (P < 0.001) being greater than that in Brahmans (15%) (P < 0.05). The intakes of both the supplemented Spear grass and the lower-N Pangola diets were significantly (P < 0.05) greater by Herefords than Brahmans. There was no breed difference in intake when the higher-N Pangola grass was supplemented. Both breeds recorded an 8% intake response to supplementation, although the increase was only significant (P < 0.05) in Herefords.4. The mean retention time of fluid in the rumen on the unsupplemented Pangola grass diet of lower N content was 12.7 h in Brahmans compared with 17.5 h in Herefords (P < 0.01). When the higher-N Pangola was fed, both alone and supplemented, the mean retention times were similar on both diets (10.5 and 9.9 h for Herefords; 9.5 and 8.1 h for Brahmans for unsupplemented and supplemented diets respectively).5. Plasma urea concentrations were higher in Brahmans than in Herefords on all diets. Rumen ammonia concentrations were significantly (P < 0.001) higher in Brahmans than Herefords when the lower-N Pangola grass diet was unsupplemented.6. The intakes and the variable intake responses to supplementation between breeds and diets are discussed in relation to a number of animal and dietary factors.

Natural hosts of pangola stunt virus (PaSV) in eastern Austalia were found to be Digitaria eriantha ssp. pentzii (pangola grass), D. ciliaris (summer grass) and D. milanjiana. Transmission tests using the planthopper vector, Sogatella kolophon, showed that D. polevansii, D. eriantha ssp. eriantha, D. swazilandensis and the Australian native, D. divaricatissima were also susceptible, whereas D. didactyla was not infected. In tests of 22 species in 15 other genera, only Urochloa panicoides (annual urochloa grass) was infected. In field surveys, PaSV was commonly found in pangola grass in near-coastal districts from Grafton, N.S.W. to Walkamin, N. Qld and was detected up to 100 km inland at Toowoomba. The virus was not detected in either pangola grass or D. eriantha ssp. eriantha in subhumid areas west of Toowoomba or at Gayndah. Sogatella kolophon was collected from Bamaga, N. Qld to Murwillumbah, N.S.W. It was commonly associated with both PaSV-infected and PaSV-free digitgrass pastures. It is concluded that PaSV poses a threat to many digitgrasses in near-coastal districts of Qld and subtropical N.S.W., but so far is unknown in inland Australia.

SUMMARYCell wall preparations from stems of four mature grass species, pangola grass, setaria, sugar cane and barley straw were incubated in nylon bags in sheep fitted with rumen cannulae and fed chopped pangola grass at hourly intervals. After varying incubation times D.M. loss, and incorporation of35S into microbial cystine on the fibres, were measured. Pangola and barley straw were digested to a much greater extent (ca.48 and 44%) than sugar cane and setaria (ca.29 and 23% respectively) and digestion was still continuing after 60 h. With the exception of setaria, microbial colonization of the cell wall preparations peaked after 24 h incubation and then declined. In setaria only a small amount of [35S]cystine was measured, the level of which did not change appreciably after 18 h.After 24 h incubation, microbial colonization on pangola fibre was about three times that on barley straw and sugar cane. Only on pangola fibre did cystine accumulation, and its subsequent rapid decline, coincide with the development and detachment of fungal sporangia. There was no relationship between the extent of microbial colonization and D.M. loss from the fibres. Sulphur concentrations, both in the plant fibres and rumen fluid, could not explain the greater fungal growth on the pangola cell walls in preference to the other species.

Feed intake, rumen function, microbial protein (MCP) production and the efficiency of MCP production were determined in steers fed four different forage hays varying markedly in crude protein content. Low quality tropical forage (speargrass and Mitchell grass) hays had lower crude protein content, higher neutral detergent fibre content and lower digestibility than a medium quality tropical forage (pangola grass) hay and a temperate forage (ryegrass) hay. Steers fed speargrass and Mitchell grass hays had lower MCP production (80 and 170 g MCP/day, respectively) and efficiency of MCP production [78 and 79 g MCP/kg digestible organic matter (DOM), respectively] than steers fed pangola grass (328 g MCP/day; 102 g MCP/kg DOM) and ryegrass (627 g MCP/day; 135 g MCP/kg DOM) hays, which was directly related to the supply of DOM and rumen degradable protein. Intake was greatest for ryegrass hay, followed by pangola grass, Mitchell grass and speargrass hays [17.6, 15.6, 10.1 and 5.5 g DM/kg W.day, respectively]. The retention time of DM in the rumen was 72.1, 47.7, 28.6 and 19.1 h for speargrass, Mitchell grass, pangola grass and ryegrass hays, respectively, with a similar trend apparent for the retention time of neutral detergent fibre, lignin, chromium-EDTA and ytterbium labelled digesta. The difference in the protein : energy ratio of absorbed substrates (measured as efficiency of MCP production) did not appear to account for all the differences in intake, nor did a purely physical mechanism.

1. Six Hereford and six Brahman steers were fed ad lib. Pangola grass (Digztaria decumbens) and Spear grass (Heteropogon contortus) hay alone and supplemented with rumen-degradable nitrogen and sulphur and minerals. The rumen digestion of the two feeds was determined by reference to the disappearance of substrate from nylon bags suspended in the rumen and withdrawn after intervals ranging from 8 to 120 h.2. The digestion of the unsupplemented Pangola grass diet occurred more rapidly in Brahmans than in Herefords and was associated with higher rumen ammonia concentrations in Brahmans (40 v. 16 mg/l). The rumen NH3, concentrations were increased to over 100 mg/l by supplementation. The digestion rate increased in both breeds after supplementation and the breed difference disappeared. Increases in digestion rate were not achieved above NH3, concentrations of 60–80 mg/l.3. Spear grass, especially the cell-wall-constituent fraction, was more resistant to digestion than Pangola grass. Digestion of the unsupplemented Spear grass diet proceeded more rapidly in Brahmans than in Herefords. The digestion rate in Brahmans were similar irrespective of whether the diet was supplemented or not. Supplementation increased digestion rate in Herefords.

SUMMARYFour silage diets were prepared from tropical grass and legume mixtures and fed to intestinally fistulated sheep to determine the sites and extent of digestion of the different silage components in the digestive tract. Pangola grass (Digitaria decumbens) was ensiled either alone or with the addition, 33% (w/w), of leucaena (Leucaena leucocephala cv. Cunningham), gliricidia (Gliricidia sepium) or cowpea (Vigna unguiculata cv. Caloona). All forages were grown at the University of Queensland farm in 1985. All silages were well preserved as indicated by low pH (< 4·1), ammonia N (< 9% total N), acetic acid (< 13 g/kg dry matter (DM)) and ethanol (< 19 g/kg DM) contents, and high DM (> 290 g/kg) and lactic acid (> 41 g/kg DM) contents. The inclusion of leucaena and gliricidia significantly increased the total N content of the silages. The addition of legumes at ensiling significantly increased rumen ammonia N (pangola 59 mg N/l, legume diets 110–115 mg N/l) and the proportion of propionic acid in rumen fluid. Sheep given pangola + leucaena silages had significantly higher DM intakes (66·3 g/kg W0·75 per day) than sheep given pangola and pangola + cowpea silages (52·4 and 53·2 g/kg W0·75 per day respectively). The inclusion of gliricidia significantly depressed silage intake (43·1 g/kg W0·75 per day). There were no significant effects of diet on DM (551–609 g/kg) and organic matter (550–612 g/rkg) digestibility. Sheep given pangola + leucaena silages had higher N intakes, N balances, rates and efficiencies of microbial N synthesis and total non-ammonia N (NAN) flows to the small intestine than did sheep given the other silages. Apparent degradabilities of silage N in the rumen were similar for all diets (0·491–0·559 g N/kg N intake), but sheep given pangola + leucaena silages had lower true (corrected for endogenous N) N degradabilities (0·648 g N/kg N intake) than those given the other diets (0·751–0·775 g N/kg N intake). The values obtained in this experiment were compared with those reported for temperate grass silages, and it was concluded that whilst the digestibility of tropical grass/legume silages was low, intakes and rumen fermentation characteristics were similar to those found for temperate grass silages.

The potential quality of the 6 pasture grasses Setaria sphacelata var. sericea cvv. Nandi, Kazungula and Narok and var. splendida, Digitaria eriantha ssp. pentzii (pangola grass), and Pennisetum clandestinum cv. Whittet (kikuyu grass) was assessed in terms of liveweight gain of beef cattle, using a leader and follower grazing system. Pasture management was designed to provide adequate quantities of young leaf to the leaders throughout the year. This was achieved by rotational grazing and weekly adjustment of the number of followers, depending on quantity of feed available. Annual liveweight gain of the leaders (kg/steer.year) ranged from 135 (kikuyu grass) to 159 (cv. Narok) (540-636 kg/ha.year). Differences between grasses on an annual basis and over summer were not statistically significant (P = 0.12), although significant differences in liveweight gain of leaders - - - were obtained during the winter. This was associated with differences between grasses in growth at lower temperatures, and in frost tolerance. Liveweight gain of the follower group was markedly higher for pangola grass and var. splendida (272 kg/ha.year) than for the other varieties (77-140 kg/ha.year). This difference was associated with differences in number of grazing days and in the superior liveweight gain per head of followers grazing pangola grass and splendida. Liveweight gain of leaders per annum was comparable for years 1 and 2 but fell dramatically from February to August in year 3. This was associated with high rainfall, reduced solar radiation, and a decrease in in vitro digestibility of plucked leaf of all setaria varieties but not of pangola or kikuyu grasses. The relatively low liveweight gains obtained in year 3 were not associated with any overall mineral or protein deficiency.

Australian cashmere weaner goats were continuously grazed on either nitrogen (N) fertilised Pangola grass or mixed tropical legume-pangola grass pastures at 3 stocking rates (15, 30, 60 goats/ha). Grazing commenced in January and was terminated in May (18 weeks). Three parasite control treatments (Seponver, Avomec, Systemex) were superimposed on each treatment. Parasite egg counts, liveweight change, cashmere growth and changes in pasture components were measured. Intestinal parasite burdens were low (<400 eggs/g faeces) in all animals throughout the trial, and there were no significant effects of parasite control treatment on goat productivity. The liveweight gain of goats decreased with increasing stocking rate and time on pasture. Mean values for the liveweight change of goats on the legume-grass pasture were 66, 37 and 14 g/day at stocking rates of 15, 30 and 60 goats/ha, respectively. Comparable values for goats grazing N-fertilised pangola grass were 40, 39 and 23 g/day for stocking rates of 15, 30 and 60 goats/ha. Goats grazing the legume-grass pastures at the lowest stocking rate (15 goats/ha) had significantly higher liveweight gains than did goats on all other treatments. There were no significant effects of stocking rate, pasture type or worm control treatment on fleece growth in these goats. Mean values were 191 g, 39 g and 15.0 �m for fleece weight, cashmere weight and mean cashmere fibre diameter respectively. The major legume in the legume-grass pasture was siratro, with axillaris, greenleaf desmodium and cassia forming minor components (10-300 kg/dry matter (DM)/ha). During the first 6 weeks of grazing, all legume components increased under stocking rates of 15 and 30 goats/ha. Thereafter, there was a significant decline in siratro yield to less than 200 kg DMha at all stocking rates. During this same period, the yields of the other legumes generally increased, suggesting that at low stocking rates the goats preferred grass to legume, and when grass was limiting, siratro was the legume preferred over all others. Weed yields increased with time in all except the high stocking rate treatments. It was concluded that weaner goat growth can be maximised on tropical legume-pangola grass pastures when stocking rates and intestinal parasite burdens are low. Protein intake may be limiting growth on N-fertilised grass pastures.

An elite genotype of Digitaria milanjiana, which had been selected on the basis of improved leaf digestibility, was compared with pangola grass (Digitaria eriantha ssp. pentzii, formerly Digitaria decumbens) in terms of milk production, at Mutdapilly in south-eastem Queensland. Unsupplemented Holstein-Friesian cows grazed nitrogen-fertilised, irrigated swards of 2 grasses using a switch-back experimental design. Pasture management and stocking rate were adjusted to provide the animals with 15 kg of green leaf (on a dry matter basis) per cow per day, so that any differences in milk yield could be attributed to differences in leaf quality rather than to total dry matter yield. Cows grazing the selected genotype produced 0.9 kg more milk, 0.07 kg more butterfat and 0.05 kg more protein per cow per day (5.8, 13.0 and 10.9%, respectively) than those grazing pangola grass. These increases were associated with a small increase in leaf digestibility, a faster rate of breakdown of leaf (in an artificial masticator) and a higher proportion of leaf in the diet chosen by the cows grazing the selected genotype. The results of this experiment demonstrate that a tropical grass selected on the basis of digestibility increased milk production of grazing cows. However, factors other than higher digestibility (such as leafiness) contributed to the improvement in production over that from pangola grass.

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In the Agreste of Pernambuco, Brazil, although many forage species are used in the pastures formation, such as pangola grass (Digitaria pentzi Stent.), sabi grass [Urochloa mosambicensis (Hackel) Dandy] and the capim-de-raiz (Chloris orthonoton Doell), there are few studies on the growth and productive responses in these plants when managed under grazing. Such studies are of great importance because it represents the starting point for understanding the responses of these plants, as well as its adaptive mechanisms, the management of pasture and semiarid environment. The objective of this study was evaluate the structural characteristics and animal performance on pasture deferred formed by grass aforementioned under nitrogen fertilization (0, 80 and 100 kg / ha) and managed under intermittent grazing in semiarid Agreste of Pernambuco. The grazing cycle was 42 days, with 14 days of grazing and 28 days of rest. The animals used in the experiment were sheep with average live weight of 25 kg. The experimental design was randomized block with split plots. In the pre-grazing, the capim-de-raiz presented had higher total forage density (102.30 kg DM/cm/ha) than the sabi grass (73.86 kg DM/cm/ha). For total forage mass and leaf blades mass, the sabi grass had lower forage and leaf blades mass (4257.67 and 1572.00 kg DM/ha) than the pangola grass (6185.48 and 2371.57 kg DM/ha) and capim-de-raiz (6153.92 and 2181.50 kg DM/ha). Regarding the effect of N levels on the structural characteristics of the pre-grazing, it was found that nitrogen fertilization of 80 kg/ha/year resulted in a smaller pasture height, greater total forage and leaf blades mass, as well as higher total forage density. In the post-grazing, forage density was higher for the pangola grass (97.89 kg DM/cm/ha), while the level of 160 kg N/ha/year provided less forage density when compared to the absence of nitrogen fertilization. As for animal performance, the pangola grass provided greater weight gain per animal and per hectare, with averages of 0.19 kg LW/animal/day and 8.3 kg LW/ha/day, respectively. The pangola grass showed better structural characteristics under grazing and provided greater animal performance when compared to capim-corrente and capim-de-raiz. Nitrogen fertilization with 80 kg/ha/year provided favorable structural characteristics in grasses. Although affect the structural characteristics of grasses under grazing, nitrogen fertilization did not affect animal performance.
No Agreste de Pernambuco, apesar de muitas espécies forrageiras serem utilizadas na formação das pastagens, tais como o capim-pangolão (Digitaria pentzi Stent.), capim-corrente [Urochloa mosambicensis (Hackel) Dandy] e o capim-de-raiz (Chloris orthonoton Doell), há carência de estudos sobre as respostas no crescimento e produtivas destas plantas quando manejadas sob pastejo. Tais estudos assumem grande importância, pois representa o ponto de partida para o entendimento das respostas destas plantas, bem como de seus mecanismos adaptativos, ao manejo da pastagem e ao ambiente semiárido. Objetivou-se avaliar características estruturais e desempenho animal em pastagens diferidas formadas pelas gramíneas citadas acima sob adubação nitrogenada (0, 80 e 100 kg/ha) e manejadas sob lotação intermitente no Agreste semiárido de Pernambuco. O ciclo de pastejo foi de 42 dias, com 14 dias de pastejo e 28 dias de descanso. Os animais utilizados no experimento foram ovinos SRD inteiros, com peso vivo médio de 25 kg. O delineamento experimental foi blocos ao acaso em parcelas subdivididas. No pré-pastejo, o capim-de-raiz apresentou maior densidade de forragem total (102,30 kg de MS/cm/ha) do que o capim corrente (73,86 kg de MS/cm/ha). Quanto a massa de forragem total e de lâminas foliares, o capim-corrente apresentou menor massa de forragem (4257,67 e 1572,00 kg de MS/ha) do que o capim pangolão (6185,48 e 2371,57 kg de MS/ha) e o capim de raiz (6153,92 e 2181,50 kg de MS/ha). Em relação ao efeito dos níveis de N sobre as características estruturais no pré-pastejo, foi verificado que a adubação nitrogenada de 80 kg/ha/ano proporcionou menor altura do pasto, maior massa de forragem total e de lâminas foliares, bem como maior densidade de forragem total. No pós-pastejo, a densidade de forragem total foi maior para o capim-pangolão (97,89 kg de MS/cm/ha), enquanto o nível de 160 kg de N/ha/ano proporcionou menor densidade de forragem total quando comparado à ausência de adubação. Quanto ao desempenho animal, o capim-pangolão proporcionou maior ganho de peso vivo por animal e por área, com médias de 0,19 kg de PV/animal/dia e 8,3 kg de PV/ha/dia, respectivamente. O capim-pangolão apresentou melhores características estruturais sob pastejo e proporcionou maior desempenho animal quando comparado ao capim-de-raiz e ao capim corrente. A adubação nitrogenada com 80 kg/ha/ano proporcionou características estruturais favoráveis nas gramíneas. A adubação nitrogenada, apesar de afetar as características estruturais das gramíneas sob pastejo, não influenciou o desempenho animal.

This study examined the differences in the chemical composition, particularly fatty acids, of the lipid extracted from the fibre of bucks, does and castrated goats. The study provides a more detailed understanding of the chemical composition of buck fibre lipid and how it varies throughout the year, and also details the effect of body region and nutrition on the production and chemical composition of lipid from buck fibre. Lipid was extracted with either petroleum ether (non-polar) or chloroform/methanol azeotrope (polar) and analysed by gas chromatography and gas chromatography-mass spectrometry. The more polar solvent system extracted larger amounts of lipid and more of each individual fatty acid. The following buck specific ethyl branched fatty acids were identified: 2-ethylhexanoic, 4-ethylhexanoic, 2-ethyloctanoic, 4-ethyloctanoic, 6-ethyloctanoic, 2-ethyldecanoic, 4-ethyldecanoic, 2-ethyldodecanoic, 6-ethyldodecanoic, 4-ethyldodecanoic, 2-ethyltetradecanoic, 6-ethyltetradecanoic, 4-ethyltetradecanoic, 2-ethylhexadecanoic and 4-ethyloctadecanoic acids. Of these buck specific fatty acids only 4-ethylhexanoic (T), 4-ethyloctanoic, 4-ethyldecanoic, 4-ethyldodecanoic, 6-ethyldodecanoic (T), 4-ethyltetradecanoic, 2-ethylhexadecanoic (T) and 4-ethylhexadecanoic acids have been previously identified or tentatively identified (T) in buck fibre extracts. This shows that the chemical composition of buck fibre lipid is more complex than previously reported, and that it may be more difficult than previously thought to artificially duplicate the odour of the buck. Buck fibre samples had lower average concentrations of 2-methylpropanoic, 2-methylbutanoic, iso-pentadecanoic, anteiso-pentadecanoic, iso-hexadecanoic, anteiso-heptadecanoic, iso-octadecanoic and anteiso-nonadecanoic acids as compared with fibre samples from does, spayed does, or wethers that were castrated at one month of age. The reduced concentrations of these fatty acids in buck fibre extracts were likely to be due to the synthesis of ethyl branched derivatives of iso and anteiso fatty acids. Buck fibre samples had higher concentrations of benzoic acid as compared with fibre samples from does, spayed does, or wethers that were castrated at one month of age. The significance of these results is that non buck specific fatty acids may also make a contribution to the odour of bucks. When fibre samples were collected at various times throughout the year, it was found that the bucks had increased amounts of lipid and ethyl branched fatty acids in fibre samples shorn from March to September, as compared with fibre samples shorn in November and January. The increase in the amount of lipid and ethyl branched fatty acids corresponded with both the rutting period of the buck and the period when the buck odour was increased. This suggests that ethyl branched fatty acids could be pheromones. The variation in lipid content and fatty acid composition was also examined between fibre samples collected from different body regions of the buck during April, as alterations in sebaceous gland activity around the neck during rutting have been reported. It was found that the average amount of lipid in the neck region of the bucks was not statistically higher than the average amounts in the midside and hind regions. However, the ethyl branched fatty acid concentrations were statistically higher in the fibre from around the neck as compared with the fibre from the other body regions, which is consistent with the odour of the buck being most pronounced around the head and neck region. The lipid content and composition of fibre samples from bucks fed high and low quality diets (lucerne and pangola grass, respectively) was examined to determine the effect of nutrition on buck specific components. The high quality diet increased the amount of lipid and ethyl branched fatty acids in fibre samples collected in April from the neck, midside and hind regions, as compared with fibre samples from the corresponding body regions from bucks fed the low quality diet. Thus it may be possible for the pheromone levels of bucks to be increased by simply providing them with good nutrition. The lipid content and ethyl branched fatty acid concentrations of fibre samples increased earlier in the year for the lucerne fed bucks as compared with the pangola grass fed bucks. The lucerne fed bucks had increased concentrations of ethyl branched fatty acids in fibre samples shorn during December to June (6 months) whereas the pangola grass fed bucks had increased concentrations of ethyl branched fatty acids in fibre samples shorn during April to August (4 months). These observations show that good nutrition can result in both the earlier production of ethyl branched fatty acids and an extended period when ethyl branched fatty acids are produced. This suggests that nutrition can be used to manipulate pheromone levels in the buck. The period when the ethyl branched fatty acids were increased corresponded with the period when the plasma luteinizing hormone (LH) and testosterone concentrations, odour and sebaceous gland volume of the bucks were increased, which supports the assumption that ethyl branched fatty acids are involved in odour production and act as pheromones.

碩士
國立屏東科技大學
機械工程系
89
The purpose of this research was to investigate the drum rotary dryer for pangola grass drying. The forage variety used was pangola grass A254. The objectives of this study were to elucidate the characteristics of this specific drum rotary dryer. The drying machine is consisted of burner, dryer, blower, cyclone, convey or et al. Experiments were proceeded according to the characteristics of the machine. The operating parameters were feed rate, particle size and excess air. Besides the drying efficiency and collection efficiency of pangola grass, analysis were carried out on the composition of crude protein, crude fat, crude fiber and trace elements of Phosphorus, Potassium, Calcium, as well as ash content of panagola grass after drying. The primary objective was set at improving the operating efficiency of this drying machine. The results showed that drying efficiency could be enhanced, if the panagola grass was pre-cut. Moreover it can increase the drying efficiency and avoid the forage clogging in the drying machine. The optimum conditions found that air velocity is about 7.1~8.3 m/s, panagola grass size 6 cm, and feed rate 10 kg/min. There was no significant difference on the approximate compositions when compared with used solar drying. It shows the potential of applying machine drying in replacing solar drying.

碩士
國立中興大學
畜產學系
90
Effect of feeding Pangola grass and fasting in early age on growth performance and carcass quality in White Roman geese Abstract The purpose of this study was conducted to investigate the effect of feeding pangola grass and different fasting time after post-hatch on the growth performance, development of digestive organs and carcass quality in White Roman geese. In trial 1, one hundred and eighty of day old geese were divided into three treatments and two replicates for each treatment. Three treatments included：(1)goslings were fed with a concentrate diet as control；(2)goslings were fed with a concentrate diet mixed with chopping pangola hay(4.5mm)；(3)goslings were fed with a concentrate diet mixed with chopping pangola grass(＜4cm). Feed and water were supplied ad libitum during 15wks experimental period. The results indicated that 0-4 weeks old goslings had least feed intake(P＜0.05) and daily body weight gain, and had significantly(P＜0.05)least body weight on 4 weeks old when birds feed with pangola hay treatment diet compared with other treatments. However, 9~13 weeks old goslings had a best daily body weight gain in birds fed with pangola hay treatment diet among three treatments. Goslings received pangola grass treatment diet had a highest body weight on 15 weeks old among three treatments thought no significantly different were discovered. The developments of digestive tracts were more fast in goslings fed with pangola hay and pangola grass groups during early stage of life. No cannibalism phenomenon were found in goslings received pangola hay and pangola grass treatment diets but there was a serious peck feather phenomenon in goslings received control diet. The contents of polyunsaturated fatty acid(PUFA) in breast muscle, thigh muscle and abdominal fat were higher when birds fed with pangola grass and pangola hay treatment diets than fed with control diet. However the content of n-3 polyunsaturated fatty acid of thigh muscle in pangola grass group was higher then the other two groups. In comparison with control and pangola hay treatment diets, birds received forage treatment diet had higher “L” and “b” value but had lower “a” value. There were more volatile flavor compounds in muscle of birds fed with pangola grass treatment diet than the other two treatments. In trial 2 the effect of access feed at different time after post-hatch on geese early growth and developments of digestive organs n geese was determined. Our data shows that the highest feed intake is obtained in treatment which geese was fed during 0 hour after post-hatch at 0-3 weeks old. The lowest data is obtained in treatment of access to feed at 72 h after post-hatch. On the daily gain, the lowest one is received feed at 72 h after post-hatch before 14 days old, and all treatments’ data is not significantly different at 14 to 21 days old. The treatment of fasting 0, 24 h after post-hatch makes geese significantly weight heavier than 72 h ones at daily gain and average body weight at 3 weeks old. As the post-hatch fasting time goes, the weight of digestive organs is lowering, and could not recover until 14 days old, and longer fasting time makes more weight reducing of digestive organs. On the other hands, shorter fasting time makes longer intestine until 14 days. Besides colon-rectum, other intestine length is not significantly different of all fasting treatments at 14 days old. Our results suggest that before 48 h post hatch is a very important stage of geese intestine growth, Suffering from fasting will result in worse growth, and also affect growth and absorbing ability of digestive organs and intestine. Keywords: geese, Pangola grass, growth performance, carcass quality, fasting time, development of digestive organs