bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of castration and subdermal silastic implants containing oestradiol-17 β-dipropionate on feedlot performance and carcass characteristics of male cattle
Authors: Schanbacher B. D. , Prior R. L. , Smith S. B. 
Published: September 2010

ABSTRACTFeedlot performance and carcass characteristics were examined in bulls and steers with and without a subdermal Silastic capsule containing oestradiol-17β-dipropionate. Castration and/or oestrogen treatment was imposed at approximately 8 months of age. The implants were removed 56 days before slaughter, i.e. 140 days after the trial commenced. Bulls gained more rapidly (12·9%), converted food to live-weight gain more efficiently (18·0%) and yielded leaner carcasses than did steers (P < 0·05). The oestrogenic implant elevated serum oestradiol concentrations substantially (> ninefold) over that of bulls and steers and induced a castration-response in the former. Serum luteinizing hormone, testosterone and testicular growth were suppressed (P < 0·05) during the first 140 days of the trial in bulls, but returned to normal following implant removal. This response was paralleled by a reduction in average daily gain (P < 0·05) and food: gain ratio (P < 0·10). Contrary to expectations, average daily gain and food: gain ratio were not significantly improved in implanted steers. Oestrogen treatment reduced hot carcass weight, loin eye area and quality grade in both bulls and steers; the last as a result of decreased marbling and internal fat deposition. Results of this study suggest that excessive oestrogen as provided in this study via the implant fails to improve feedlot performance and carcass merit in steers and may, in fact, diminish the inherent anabolic attributes of the intact male. Additional studies are required to understand the complex interactions of androgens and oestrogens in the regulation of body growth and composition of male cattle.
Hormonal changes in post-partum blood plasma and milk of buffaloes (Bubalus bubalis)
Authors: Pahwa G. S. , Pandey R. S. 
Published: September 2010

ABSTRACTPost-partum changes in the concentration of progesterone, oestradiol-17β and prolactin were measured by radioimmunoassay in the blood plasma and milk of 28 buffaloes. The mean concentration of progesterone in the plasma of normal animals was 0·24 ± 0·04 μ.g/1 on the day of calving and decreased linearly during the post-partum period, until the complete regression of the residual corpus luteum of pregnancy occurred, when the plasma concentration was recorded as 0μ05 to 0μ08 μg/l. The concentration at a silent oestrus was 0μ17 ± 0·02 μ.g/1. The milk progesterone profile was parallel to that of plasma but the level was 2 to 4 times higher.The mean concentration of oestradiol-17β in plasma was 41·0 ± 2·34 ng/1 on the day of calving; it declined significantly by day 1 post partum (P < 0·001) and fluctuated between 8 and 16 ng/1 until oestrus, when the concentration was approximately 25 ng/1. The oestradiol-17β concentration in milk was significantly higher than that of plasma on the day of calving. During the first 20 days post partum, a similar concentration of oestradiol-17β was maintained in both fluids but thereafter the concentration in milk was 2 to 3 times that of plasma.The mean concentration of prolactin in plasma was 212·6± 19·08 μg/1 on the day of calving and then declined and fluctuated between 70 and 270 μg/1 during the rest of the period. A minor elevation occurred around oestrus. The prolactin concentration for the first 2 days post partum in milk was significantly higher than that in plasma but during the rest of the period it was similar to that in plasma.The progesterone concentrations were slightly lower in anoestrous animals than in those cycling. The concentration of prolactin was significantly higher in multiparous animals (P < 0·001), whilst the progesterone and oestradiol values were similar in primiparous and multiparous animals.
Amino acid requirements of growing pigs 4. Methionine plus cystine
Authors: Taylor S. J. , Cole D. J. A. , Lewis D. 
Published: September 2010

ABSTRACTThe response of the growing female pig (25 to 55 kg live weight) to increasing dietary methionine plus cystine concentrations was assessed by measurement of growth rate, food utilization, ham dissection and changes in blood metabolite concentrations. A range of 13 methionine plus cystine concentrations from 3·5 to 5·79 g/kg resulting from combinations of three basal diets and synthetic methionine, was studied. The diets were formulated using barley, a yeast protein, tapioca and synthetic amino acids to contain similar energy concentrations, 9·5 g lysine per kg diet, and adequate concentrations of other essential amino acids and non-essential nitrogen. They were offered once daily according to a restricted feeding scale.Responses were interpreted by broken line functions which indicated, from the growth performance experiment, a requirement between 4·5 and 4·8 g/kg of the diet, when the complete range of methionine plus cystine concentrations was studied. The influence of a range of dietary methionine plus cystine concentrations from 4·1 to 5·3 g/kg diet on changes in plasma urea, methionine, lysine and threonine concentrations indicated a requirement for methionine plus cystine of 4·5 g/kg of the diet.
Correlated responses in lamb mortality due to long term selection for cannon bone length and fleece medullation in sheep
Authors: Cue R. I. 
Published: September 2010

ABSTRACTLamb mortality in a Scottish Blackface hill sheep flock subjected to long term selection for cannon bone length and fleece medullation score was investigated, using maximum likelihood analyses. The selection for cannon bone length and for medullation score had no significant effect on lamb mortality.
The use of blood metabolites in the determination of energy status in beef cows
Authors: Russel A. J. F. , Wright I. A. 
Published: September 2010

ABSTRACTThe objective of the studies reported was to examine the potential usefulness of measurements of concentrations of plasma glucose, 3-hydroxybutyrate and non-esterified fatty acids as means of assessing in quantitative terms the adequacy of energy intake of beef cattle.Relationships between the concentrations of these metabolites and of either energy intake or energy status were examined in three experiments conducted respectively on 56 housed, mature, non-pregnant, non-lactating cows, on 115 housed, mature, pregnant cows, and on groups of 10 to 12 mature, non-pregnant, non-lactating cows grazing five plant communities.The results indicated that under the conditions pertaining in these studies plasma glucose concentration was not likely to constitute a useful index of energy status in housed or grazing animals.Plasma 3-hydroxybutyrate concentration was closely related to estimates of energy status in the pregnant cows and was considered to be potentially valuable as an index of energy status in animals in which there is a relatively high glucose demand.Plasma non-esterified fatty acids concentration was closely related to and a potentially useful index of either energy intake or energy status in all cases, but postulated effects of diurnal variations in circulating concentrations make it imperative that relationships used for predictive purposes are derived under the conditions in which they are to be applied.
Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 2. Energy metabolism
Authors: Close W. H. , Stanier M. W. 
Published: September 2010

ABSTRACT1. Measurements of heat loss, energy and nitrogen balance were made on 18 groups of piglets weaned at 2 weeks, at environmental temperatures of 18, 23 and 28°C, and at three levels of feeding at each temperature.2. From the experimental results, values of heat loss, energy retention, protein and fat deposition were derived for each temperature, at each of the three levels of metabolizable energy (kJ/kg M0·75 per day) intake: 550 (1·0MEm), 825 (1·5MEm) and 1100 (2·0MEm). The lowest of these levels was the calculated thermoneutral maintenance energy requirement (MEm).3. From the results the following deductions were made, (a) Heat loss varies with both environmental temperature and metabolizable energy intake, and at an intake of 2·0MEm is minimal between 23 and 28°C. Energy retention varies in an inverse manner to heat-loss, and at 1·0MEm is negative at all environmental temperatures below 28°C. (b) Protein and fat deposition increase significantly with increase in metabolizable energy intake (P < 0·05), with fat deposition being more dependent on temperature than protein deposition. The mean increase in protein deposition per 1°C increase in environmental temperature is 2·05 kJ/kg M0·75 per day. Fat deposition is negative at all temperatures at l·0MEm; at l·5MEm it is zero at 23°C and negative at temperatures below this.4. Critical temperature was calculated to decrease from 26·9°C at l·0MEm to 23·9°C at 2·0MEm.5. The efficiency of energy utilization (k) was 0·58 at 18°C, 0·81 at 23°C and 0·74 at 28°C. The corresponding values of the maintenance energy requirements were 739, 615 and 550 kJ/kg M0·75 per day. Estimates of the energetic efficiency of protein deposition (kp) of 0·60 to 0·65, and of fat deposition (k/) of 0·82 to 0·86, were determined at 23 and 28°C.
The effect of nutrition on the reproductive performance of first-litter sows 1. Feeding level during lactation, and between weaning and mating
Authors: King R. H. , Williams I. H. 
Published: September 2010

ABSTRACTA factorial experiment was conducted with 80 first-litter sows and involved two levels of feeding during lactation (ad libitum or 2·0 kg/day), and two levels of feeding between weaning and mating (4·0 or 1·5 kg/day).Average lactation length was 32·2 days. Sows given 2·0 kg/day during lactation lost more backfat (6·3 v. 0·9 mm; P < 0·05) and more live weight (36·8 v. 9·1 kg; P < 0·05) during lactation than sows fed ad libitum and whose average daily food intake was 4·47 kg. Sows receiving 20 kg/day during lactation took longer to return to oestrus after weaning. Within 8 days of weaning more sows fed ad libitum during lactation ovulated (0·90 v. 0·40; x2 = 20·0; P < 0·001) and exhibited oestrus (0·78 v. 0·38; x2 = 12·8; P < 0·001) than sows whose food intake throughout lactation was restricted. Ovulation rate, subsequent litter size and embryonic mortality were not significantly affected by feeding level during lactation.Post-weaning feeding level did not affect the interval between weaning and oestrus. However, sows receiving 4·0 kg/day between weaning and mating had higher ovulation rates (14·8 v. 13·0; P < 0·05) and a greater litter size (10·0 v. 8·8; P < 0·1) at the subsequent farrowing.
The effect of genotype and metabolizable energy intake on protein and fat gain in veal calves
Authors: Meulenbroeks J. , Verstegen M. W. A. , Van der Hel W. , Korver S. , Kleinhout G. 
Published: September 2010

ABSTRACTAn experiment was carried out with 20 male veal calves to study differences in energy metabolism between pure Dutch Friesian and Holstein Friesian crossbred calves, containing a high proportion of Holstein Friesian genes (0·79). Two metabolizable energy (ME) intakes were given. The effects of genotype and ME intake on live-weight gain and its fat and protein composition were measured by indirect calorimetry and by the total collection of faeces and urine. Energy and nitrogen balances were measured for each calf during the last 5 weeks of the fattening period of 22 weeks.The difference in live-weight gain between the Holstein Friesian crossbreds and the Dutch Friesian calves was not significant but small differences in protein and fat composition of live-weight gain were found. Fat gain was closely related to ME intake (r = 0·95), but the correlation coefficient between ME intake and protein gain was only 0-36. Live-weight gain had a high correlation with protein gain (r = 0·70) but a lower correlation with fat gain (r = 0·29).Veal calves at the end of the fattening period had a declining protein gain as age increased. Calves given a high ME intake (> 2 × maintenance) may require diets containing less than 216 g crude protein per kg diet at the end of the fattening period.The study indicates that Holstein Friesian crossbred veal calves and Dutch Friesian veal calves have similar ME requirements.
The effects of dietary fibre, source of fat and dietary energy concentration on the voluntary food intake and performance of growing pigs
Authors: Campbell R. G. , Taverner M. R. 
Published: September 2010

ABSTRACTNinety entire male pigs were used in two experiments to investigate the effects of energy concentration on the performance of growing pigs given diets containing relatively high or low levels of fibre. A blended fat product was also compared with tallow as a source of dietary energy for pigs in the first experiment.In experiment 1, 60 pigs growing between 20 and 45 kg live weight were given 10 diets containing approximately 120 g acid-detergent fibre per kg (80 g crude fibre per kg), and 10, 30, 50, 75 or 100 g/kg of either tallow or the blended fat product.Although the source of fat had no significant effect on food intake or growth performance, voluntary energy intake and growth rate increased with increase in the level of fat added to the diet and with concomitant increase in dietary digestible energy (DE) concentration up to 50 g/kg and 13·2 MJ/kg respectively. Further increase in the level of fat added to the diet and in DE concentration resulted in a decline in voluntary food intake, whilst energy intake and growth rate remained relatively constant at 27 MJ/day and 720 g/day respectively.In experiment 2, 30 pigs were used to investigate the animals' response to five levels of dietary DE concentration (11·8 to 15·1 MJ DE per kg) between 20 and 50 kg live weight. The highest level of acid-detergent fibre in the diets was 62 g/kg (50 g crude fibre per kg) and this declined with increase in energy concentration to 30 g/kg (25 g crude fibre per kg) in the diet of highest energy concentration.Voluntary food intake was not significantly affected by dietary energy concentration, and voluntary energy intake and growth rate increased linearly with increase in dietary energy concentration up to 14·5 MJ DE per kg. Maximum energy intake (31 MJ DE per day) and growth rate (905 g/day) in experiment 2 was proportionately 0·15 and 0·26 higher than that achieved by pigs given the higher fibre diets in experiment 1.The results for voluntary food intake and growth rate suggested that the pig's demand for energy and consequently its response to dietary energy concentration was affected by dietary fibre concentration.
Comparative determination of beta-adrenergic receptors in muscle, heart and backfat of Piétrain and Large White pigs
Authors: Böcklen E. , Flad S. , Müller E. , von Faber H. 
Published: September 2010

ABSTRACTThe number of beta-adrenergic receptors which influence the effectiveness of catecholamines was determined by 3H-dihydro-alprenolol in muscle, heart and fat tissue of stress-susceptible pigs (Pietrains) and non-susceptible pigs (Large Whites). In all investigated tissues proportionately 0·31 to 0·38 more receptors were found in the Pietrains than in the Large Whites, the differences being significant (P< 0·05). That the higher numbers of beta-adrenergic receptors in Pietrain pigs may be involved in accelerated muscle glycogenolysis (poor meat quality) and increased lipolysis (low carcass fat) in these animals and in other breds showing poor meat quality and low carcass fat is discussed.
A study of sexual development in ram lambs
Authors: Al-Nakib F. M. S. , Lodge G. A. , Owen J. B. 
Published: September 2010

ABSTRACTTwo experiments were designed to study the effect of rearing method, female company, and repeated libido and semen tests on the pattern of sexual development of ram lambs. Four artificial rearing treatments (AR) were compared with natural rearing (NR) in one experiment and four artificial compared with three natural rearing treatments in a second experiment. Lambs on AR treatments in both experiments, as well as naturally reared lambs in the second experiment, were reared with or without females either before and/or after weaning. Half the lambs in the second experiment were libido and semen tested, and their mean plasma testosterone level was also measured, while the rest were only tested at the end of the experiment. The effect of method of rearing and female company on body growth, testes diameter, libido and semen quality were also investigated.A close relationship was found between body weight and sexual characteristics (for example, testis diameter, semen traits, libido, testosterone level and age at the onset of sexual maturity). NR resulted in faster growth than AR but was not appreciably different from early weaned-naturally reared treatments. It was also observed that mating performance improved steadily with advancement in age and increase in body weight. The onset of sexual maturity was attained at a minimum of 23 kg body weight and a minimum of 198 days of age. However, the heavier the lamb when sexually mature, the better its mating performance.Previous libido tests of ram lambs improved their subsequent mating performance, but had no effect on semen quality. However, libido tests did not improve the performance of those ram lambs which did not exhibit initial libido.It is suggested that early weaning at 2 months of age could be a suitable system for ram lambs weaned off their mothers for breeding purposes. These lambs should be reared as an all-male group but libido tested at monthly intervals commencing at 3 months of age. The criteria for selecting these lambs at an earlier age should be body weight and testis diameter.
Performance of British Landrace pigs selected for high and low incidence of halothane sensitivity 2. Growth and carcass traits
Authors: Webb A. J. , Simpson S. P. 
Published: September 2010

ABSTRACTThe effects of halothane phenotype on growth were estimated from generations 1 to 3 of British Landrace positive and negative selection lines. A total of 241 full-sib pairs (castrated male and gilt) from 133 second litters were performance tested from 25 to 85 kg live weight on either ad libitum or scale (0·69 g/g ad libitum daily food intake) feeding.Compared with negative reactors over feeding regimes, positive pigs showed significant advantages in food conversion ratio (−0·07, s.e. 0·02), eye-muscle area (0·8, s.e. 0·3 cm2), proportion of lean in sample joints (16, s.e. 7 g/kg), and visual conformation scores, accompanied by disadvantages in meat colour (5·9, s.e. 2·1 EEL units), incidence of pale, soft, exudative (PSE) meat (0·36 v. 0·05, P < 0·001), post-weaning mortality (0·09 v. 0·01, P < 0·001) and ad libitum daily food consumption (−0·08, s.e. 0·02 kg). In addition, there were non-significant indications of an advantage in carcass lean proportion (11, s.e. 10 g/kg), with disadvantages in carcass length (−14, s.e. 7 mm) and proportion of lean in high-priced cuts (−6, s.e. 2 g/kg). Only daily food consumption showed significant selection line × feeding level interaction.Averaged over feeding regimes, an estimated extra return of £1·70 (s.e. 0·50) from lean growth would be offset by increased PSE and mortality to give a net loss of roughly £3·90 (s.e. 1·00) per positive reactor. Taking these results as the minimum difference between homozygotes, and if the gene is additive for lean proportion but recessive for stress susceptibility, the heterozygote would have an advantage of £0·90 over the normal homozygote. The effects of the gene on growth and carcass traits in British Landrace appear similar to those reported in other breeds, although the advantage of positive reactors in lean proportion may be slightly smaller.
Protein nutrition of growing cattle: food intake and growth responses to rumen degradable protein and undegradable protein
Authors: Newbold J. R. , Garnsworthy P. C. , Buttery P. J. , Cole D. J. A. , Haresign W. 
Published: September 2010

ABSTRACTGroups of eight Friesian steers were given one of eight diets from 114 to 300 kg live weight. The iso-energetic diets were formulated to supply four levels of protein degradability within two concentrations of crude protein (CP), giving a range of rumen-degradable protein (RDP) and undegradable dietary protein (UDP) concentrations both above and below Agricultural Research Council (1980) recommendations. There were significant (P < 0·05), positive, linear responses of mean daily dry-matter (DM) intake (DMI) (g/kg M°75) to RDP concentration (g/kg DM) for both the low CP diets (DMI = -98·0 + 1·76 (RDP); P = 0·013) and the high CP diets (DMI = -157·5 + 218 (RDP; P = 0017). For the high CP diets, there was a significant (P = 0·045) positive, linear response of live-weight gain (LWG) (kg/day) to UDP concentration (LWG = 0·47 + 0·017 (UDP); P = 0·045). No such response was observed for the low CP diets, where the range of UDP concentrations supplied was smaller than expected. For both the low and high CP diets, LWG decreased as metabolizable energy, UDP and RDP intake increased. These negative responses to nutrient intake were reflected in a wide discrepancy between observed rates of gain and those predicted by current energy and protein nutrition systems. Interactions between food intake and digestive processes, which obstruct effective interpretation of these results, should form an explicit part of any revised protein nutrition scheme.
Carcass composition of veal calves dependent on genotype and feeding level
Authors: Korver S. , Vos H. , Bergström P. L. , Verstegen M. W. A. , Kleinhout G. 
Published: September 2010

ABSTRACTDutch Friesian purebred and Holstein Friesian-Dutch Friesian crossbred veal calves were used to study effects of genotype and feeding level on carcass composition. Carcass analyses were carried out on a total of 56 calves of two genotypes. Calves were reared for 22 weeks and given food dependent on age. From 1 to 16 weeks calves were given the same amount of milk replacer. At week 16, calves were assigned to either a high or low feeding level. Total energy intakes for the two groups were 5062 MJ metabolizable energy (ME) and 5408 MJ ME, respectively. Carcass weight and carcass composition traits showed no significant interaction between genotype and feeding level. Dutch Friesians had higher lean: bone ratios than Holstein Friesian crossbreds (3·85 v. 3·67). Differences between the two genotypes for fat and lean proportions in the carcass were not significant. Average proportions for lean and fat were 653 and 134 g/kg.Differences between the two feeding levels for carcass composition were significant. Calves on the low feeding level had 655 g lean and 131 g fat per kg, while calves on the high level had 645 g lean and 143 g fat per kg.The influence of the dissection technique on the differences in lean and muscle proportion between groups was studied on 18 carcasses using a standardized butcher's method (the Institute of Animal Husbandry (IVO) standard method) and the European Economic Community (EEC) reference method for beef. Average proportion of lean was 640 g/kg by the IVO method and of muscle was 557 g/kg by the EEC method. The difference between the two genotypes for lean proportion was smaller by the' EEC method due to the more complete separation between muscle and fatty tissue. Dutch Friesians had more intermuscular fat than Holstein Friesian crossbreds. Results of the EEC reference method indicate differences between the two feeding levels for fat as well as for protein deposition.