bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental factors affecting beef cow reproductive performance in Botswana
Authors: Buck N. G. , Light D. , Rutherford A. , Miller M. , Rennie T. W. , Pratchett D. , Capper B. S. , Trail J. C. M. 
Published: September 2010

SUMMARYEffects on cow reproductive performance, of cow age, parous state, body weight and body-weight change over the breeding season were examined using 6490 annual records from indigenous cows in Botswana.Calving percentage rose from 69% at 2·5 yr of age to a maximum of 82% at 6 to 7 yr and declined in cows over 8 yr of age. Heifers and previously non-parous cows had a calving percentage of 85%; 8, 18 and 30% higher respectively than parous cows that had calved at the beginning, middle and end of the previous calving season. Cows weighing less than 300 kg at the beginning of the mating season achieved a 50% calving. This rose steadily to 85% as body weight increased to 430 kg.Cows that lost weight over the mating period achieved a 67% calving, while gains of 20 kg raised this to 76%. Increased weight gains thereafter had little effect on calving percentage. In all cases, as percentages increased, days to conception decreased in a similar manner.Under these range conditions in Botswana, animals least likely to achieve high calving percentages were young cows; cows which calved previously at the end or middle of the calving season; cows less than 310 kg in weight; and cows gaining less than 20 kg body weight during the mating season.
Alternative forms of genetic controls
Authors: Smith C. 
Published: September 2010

SUMMARYThe optimum design of genetic controls is considered with respect to several factors, such as a fixed total expenditure, differing costs for males and females, different plans for retaining parents and choosing replacements, the value of keeping spares and the effects of mortality and infertility among individuals in the control.The effects of mortality and infertility are important for these will tend to reduce the annual effective size and lower the optimum age for replacement of parents. Keeping individuals to a fixed age, without spares, will usually be preferable in practice to the lifetime retention of parents with spares, since spares will be at the expense of other breeding animals. It is shown that with the same total expenditure, the annual effective size of a control may be substantially increased by the appropriate choices among the various factors studied and methods are given for finding the optimum design.
Herbage intake and performance of grazing ewes and of their lambs when weaned at 6, 8, 10 or 14 weeks of age
Authors: Gibb M. J. , Treacher T. T. , Shanmugalingam V. S. 
Published: September 2010

ABSTRACTTwin lambs grazing with their dams at herbage allowances of 30 or 60 gdry matter per kg live weight per day (low and high, respectively) were weaned at 6, 8, 10 or 14 weeks of age. After weaning, the lambs were given a herbage allowance of 160 g dry matter per kg live weight per day.Ewes on the low allowance ate less herbage, produced less milk and lost more weight than those on the high allowance. The lambs on the low allowance were lighter at weaning than those on the high allowance (137 v. 168, 16·2 v. 20·5, 17·9 v. 24·2 and 21·9 v. 30·4 kg at 6, 8, 10 and 14 weeks respectively).Lambs weaned from ewes on the low allowance grew more slowly than the unweaned lambs when removed at 6 weeks, but not when weaned at 8 and 10 weeks of age. Weaning lambs from ewes on the high allowance reduced their growth rates at all weaning ages, despite the weaned lambs being grazed at an allowance which would not limit their intake of herbage. The intake of herbage per unit live weight by weaned lambs reached its maximum at approximately 8 weeks of age. After weaning, intake was higher for lambs from ewes on the low allowance than for those on the high allowance (38 v. 33 g organic matter per kg live weight per day). Lambs slaughtered at 17 weeks of age were heavier from the high allowance than from the low allowance. However, after 17 weeks of age the remaining lambs from the low allowance grew more rapidly than those from the high allowance, and when slaughtered at 25 weeks of age had similar weights. Treatments had no effect on the weights of the body components or carcass dimensions independent of their effect on empty-body weights at slaughter.
Effect of body condition and pasture type on herbage intake, performance during lactation and subsequent ovulation rate in Scottish Blackface ewes
Authors: Doney J. M. , Gunn R. G. , Peart J. N. , Smith W. F. 
Published: September 2010

ABSTRACTScottish Blackface ewes in uniform, good, body condition at mating were differentially fed during pregnancy, such that two groups lost 0·15 to 0·20 (groups A and B) and one group gained 0·05 (group C) of maternal live weight by lambing time. The treatments had little effect on the number of lambs born per ewe lambing (1·39, 1·46 and 148 respectively).Prior to parturition, group A was transferred to a poor hill pasture, and groups B and C to an improved upland reseeded pasture. Herbage intake by six single- and six twin-suckling ewes from each group was estimated in the 3rd, 6th and 8th week after parturition, and mean daily milk production was estimated on 1 day following each intake measurement period. Herbage intake by six dry ewes in each of groups A and B was also estimated.There were significant differences amongst groups A, B and C, respectively, in mean organic matter digestibility of the herbage consumed (0·701, 0·771 and 0·773), mean daily digestible organic-matter intake (1·06, 1·46 and 1·46kg), mean live-weight change over the period ( –2·9, +5·4 and +l·3kg) and mean daily milk yield (0·64, 1·93 and 1·95 kg).By the following mating time, after grazing the same pasture from weaning, there was still a difference in body condition score according to pasture type during lactation (2·08, 2·36 and 2·29, respectively). Ovulation rate measured after mating was consistent with the direct effect of body condition (1·34, 1·56 and 1·52, respectively).
Some behavioural deviations in weaned domestic pigs: persistent inguinal nose thrusting, and tail and ear biting
Authors: Blackshaw Judith K. 
Published: September 2010

ABSTRACTGroups of pigs were observed from weaning to marketing for the incidence of tail and/or ear biting and persistent inguinal nose thrusting. The 16 groups included single and mixed litters, single or mixed-sex ratios, and comprised up to 12 pigs; 14 of the groups showed biting behaviour and 12 groups showed persistent inguinal nose thrusting behaviour. The onset of biting appeared from 0 to 44 days after weaning, and persistent inguinal nose thrusting was first observed 4 to 22 days after weaning.There was a significant relationship between the number of pigs biting and being bitten in a group. The high ranks tend to bite middle and low ranks more than expected, the middle ranks bite other middle ranks more than expected, and low ranks bite the least. Within any rank there was no difference between male and females biting or being bitten. The most common situation was to have, in a group, some pigs which only tail bit, others that only ear bit, and others which both tail and ear bit. It is suggested that biting is a learned response spread by visual communication, so that visual barriers around affected groups may help to limit the spread of an outbreak.In persistent inguinal nose thrusting behaviour, rank was important, as the top ranking pigs were the most most likely to show persistent inguinal nose thrusting. Persistent inguinal nose thrusting may have its origin in udder seeking, exploratory or rooting behaviour, but becomes used mainly by dominant pigs. The behaviour is halted by the pig which received the nose thrusts moving away.
A note on the effect of low levels of biotin in milk substitutes for neonatal pigs
Authors: Newport M. J. 
Published: September 2010

ABSTRACTPigs weaned at 2 days of age were given a milk substitute until 28 days of age containing either 10 or 52 fig biotin per kg dry matter. During the last week of the experiment a slight deterioration in the ratio of feed: gain (0·1 > P > 0·05), but not in weight gain, was found in pigs given the low-biotin diet. No signs of biotin deficiency were observed, but pigs given the low-biotin diet had lower concentrations of biotin in the liver and carcass. Most of the biotin was in the liver. These results suggest that 10 fig biotin per kg dry matter may be adequate for pigs until at least 28 days of age.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 2. Chemical and dissectible body composition
Authors: Thompson J. M. , Butterfield R. M. , Perry Diana 
Published: September 2010

ABSTRACTThe changes in chemical and dissectible body composition from birth to maturity were examined in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. Body composition was examined in 34 mature animals and the maturing patterns for body components calculated using mean values from the mature animals and individual data from 106 immature animals.In the 34 mature animals, strain had no effect on the proportions of chemical and dissected fat, protein and muscle in the body. The weight-plus had greater proportions of ash and carcass bone in the body than the weight-minus animals. Mature rams had lower proportions of chemical and dissected fat and greater proportions of protein, muscle, ash and carcass bone in the body than mature ewes.The weight-minus animals had later maturing patterns for both chemical and dissected fat than the weight-plus animals. Strain had no effect on the maturing patterns for protein and muscle, although both ash and carcass bone were later maturing in the weight-plus, than in the weight-minus animals. Chemical and dissected fat were later maturing in the ewes than in the rams, whereas protein, muscle, ash and carcass bone were earlier maturing in the ewes than in the rams.The weight-minus animals were fatter at the heavier body weights, although there was a trend for the weight-plus animals to be slightly fatter at the lighter body weights. When compared at the same stage of maturity of body weight, strain differences in the proportion of fat in the body declined as the animals matured. Compositional differences between the rams and ewes varied according to the body weight or stage of maturity of body weight at which they were compared.
A comparison of carcass traits in Scottish Blackface and Welsh Mountain lambs and their crosses
Authors: Lee G. J. 
Published: September 2010

ABSTRACTA total of 219 lambs of the Welsh Mountain (W) and Scottish Blackface (B) breeds, and six types of crossbred with varying proportions of the two breeds from a cyclical crossbreeding experiment, were slaughtered in six groups at fortnightly intervals from 6 to 8 months of age. Each group had balanced numbers of each genotype and each sex. Genotype differences and effects of heterosis were estimated. Fat grades were assessed by farm staff before slaughter and Meat and Livestock Commission fat and conformation scores and external linear hindquarter measurements of each carcass were recorded.At the same age, W carcasses were lighter (W: B = 0·86, W = 11·7 kg, B = 13·4 kg) but were more mature and had more kidney fat (W: B = 1·73) and higher fat and conformation scores especially in the loin region, but relatively shorter, thinner legs. At the same degree of maturity (carcass weight/estimated mature carcass weight), the Welsh carcasses had more kidney fat but the difference in leg measurements was reduced, and the differences for fat and conformation scores disappeared. When compared at the same grade, the Welsh lambs were 2 kg lighter and had higher conformation scores suggesting comparative undergrading, especially by the farm assessors. Results for crossbred lambs were as predicted from their breed composition and there was no evidence of heterosis.The results suggest that at the same estimated carcass fatness, the Blackface has the potential to produce a heavier carcass but is later maturing, taking approx. 12 days longer to reach this degree of fatness.
Dietary amino acid balance and requirements for pigs weaned at 3 weeks of age
Authors: Zhang Y. , Partridge I. G. , Keal H. D. , Mitchell K. G. 
Published: September 2010

ABSTRACTNitrogen balance was measured in a series of experiments to determine the optimum balance between lysine, threonine and methionine plus cystine by successive additions of the free amino acids to a basal diet of barley, soya bean meal and tallow. The basal diet had a calculated digestible energy (DE) value of 14·5 MJ/kg and a crude protein content of 146 g/kg. The ranges of total lysine; threonine and methionine plus cystine tested were (g/kg) 6·6 to 11·8, 4·9 to 6·9 and 4·3 to 71, respectively. Latin-square designs were used involving a total of 33 pigs. Nitrogen utilization was optimized in pigs of 3 to 9 weeks of age when each kg of diet contained 10·5 g lysine, 6·4 g threonine and 5·0 g methionine plus cystine, corresponding to a ratio of 100: 61: 48. Thereafter, five diets were formulated in which the same ratio was maintained, but at different protein levels (129 to 192 g/kg). Again the diets were based on barley, soya bean meal and tallow supplemented with free amino acids. These diets were compared, in both nitrogen balance and performance experiments, with a conventional early-weaning diet with a protein content of 240 g/kg. All six diets had the same calculated DE value (14·5 MJ/kg). The N balance experiment was of Latin-square design and involved 18 pigs, and the performance experiment used 36 pigs fed individually from 3 to 9 weeks of age. A diet containing 0·99 g lysine per MJ DE (14·4 g lysine and 192 g balanced protein per kg) was considered to be adequate on the basis of the growth rate and food conversion efficiency results obtained.
Combining clonal response and genetic response in dairy cattle improvement
Authors: Teepker G. , Smith C. 
Published: September 2010

ABSTRACTRepeated cloning of bovine embryos by nuclear transfer, producing large clones of monozygous animals, may be possible in the future. Initially, clones could be tested and the best one selected and spread over the commercial population by embryo transfer. Further genetic improvement could be obtained by rebreeding a number of the best clones to produce a new set of clones. However, the testing and selection systems to pick the best clone (for short-term clonal response) and to pick clones with the best breeding values (for long-term genetic response) are different. The objective of this study was to derive a system which achieves both high clonal and high genetic responses. An adult MOET (multiple ovulation and embryo transfer) scheme with 40 breeding males and 40 breeding females per generation (cycle) was used to maintain adequate genetic variation for continued genetic response. For a fixed set of testing facilities and a given family structure initial clonal response is maximized by testing several members per clone. Long-term genetic response is usually greatest when testing one member per clone. Compromises to obtain both high clonal response and high genetic responses were from 95 to 100% efficient.
Effects of low levels of food intake before and/or after mating on gonadotrophin and progesterone profiles in Greyface ewes
Authors: Rhind S. M. , McMillen S. , Wetherill G. Z. , McKelvey W. A. C. , Gunn R. G. 
Published: September 2010

ABSTRACTGonadotrophin profiles during the follicular phase of the cycle prior to a synchronized mating and LH and progesterone profiles at days 2, 6 and 10 post mating were investigated in three groups of 16 ewes. of one group were given 0·5 × estimated metabolizable energy requirements for maintenance (MEM) from 14 days before mating until slaughter 11 days after mating (LL). Ewes of a second group were given 1·5 × MEM during the 14 days prior to mating and then 0·5 × MEM thereafter (HL) and the remaining ewes (HH) were given 1·5 × maintenance throughout the experiment. During the day before mating, plasma samples were collected at 10-min intervals for 8 h and assayed for LH and FSH. Samples were collected at 15-min intervals for 8 h on days 2, 6 and 10 after mating. Each ewe was then injected intravenously with 10 μg LH and samples were collected for a further 3 h. All of these samples were assayed for LH and progesterone. Nutritional treatment did not affect mean follicular phase concentrations of FSH or LH or mean LH pulse amplitude but the mean LH pulse frequency (pulses per h) of LL ewes was lower than that of HH + HL ewes (0·37 v. 0·48; P < 0·05). After mating, mean LH concentrations were unaffected by sampling date or nutritional treatment but the mean LH pulse frequency was lower in HL + LL than HH ewes at day 2 (0·25 v. 0·40; P < 0·01) and day 10 (0·28 v. 0·38; P < 0·05). Mean progesterone concentrations (ng/1) were higher in HL + LL than HH ewes at day 10 (6·77 v. 4·80; P < 0·05) but pulse frequency was not significantly affected. Injection of 10 μg LH on days 2, 6 and 10 after mating was followed by a significant increase in progesterone concentrations. The progesterone response was greater (P < 0·05) in LL + HL ewes than in HH ewes. It is concluded that increased rates of embryo mortality often associated with undernutrition are unlikely to be related to lower circulating progesterone levels per se but may be attributable to reductions in mean LH pulse frequency and consequent changes in progesterone profiles.
The influence of season and management system on intake and productivity of confined dairy cows in a Mediterranean climate
Authors: Moran J. B. 
Published: September 2010

The influence of season and management system on the productivity of Friesian cows in a Mediterranean climate was assessed. Intakes of food and water and milk yields were measured in 154 cows over 2·5 years while intensively managed in yards giving access to shelter (free stalls) or that were fully exposed to solar radiation (open lots). Food quality was also monitored to permit estimates of the efficiency of utilization of metabolizable energy for milk production over fortnightly periods.The highest milk yields and energetic efficiencies were recorded during spring. Energy intakes were highest but energetic efficiencies were lowest during winter. Cows consumed the least food during summer and autumn and drank the most water during summer. The only significant effect of management system was for water intake, which was higher in the open lots than in the free stalls. There was evidence of heat stress in summer and cold stress in winter, but there appeared to be little benefit with milk yields through the provision of shelter.
Growth, carcass composition and serum hormone responses to photoperiod and ovariectomy in heifers
Authors: Zinn S. A. , Chapin L. T. , Enright W. J. , Tucker H. A. 
Published: September 2010

ABSTRACTTo determine effects of photoperiod and ovaries and their interactions on live-weight (LW) gain, carcass composition, growth hormone (GH), insulin (INS) and prolactin (PRL), crossbred beef heifers were utilized. Heifers (no. = 70) were blocked by LW and assigned to a pre-treatment slaughter group for estimation of initial carcass composition or to treatments in a 2 × 2 factorial experiment (no. = 14 per treatment). Main effects were: photoperiod (8 h light (L): 16 h dark (D) v. 16L: 8D) and ovaries (intact (INT) v. ovariectomized (OVX)). Heifers were given a maize-based mixed diet (115 g protein and 11·5 MJ metabolizable energy per kg dry matter) ad libitum once per day at 07.30 h. On days 64 and 138, blood samples were taken every 30 min for 10 h from five heifers in each treatment. On day 144 treated heifers were slaughtered. Relative to OVX heifers, INT heifers had greater (P < 0·01) average LW gain (1·03 v. 1·17 kg/day), carcass weight (252 v. 270 kg) and carcass protein accretion rates (68 v. 82 g/day) but carcass fat accretion was not affected (P < 0·l; 381 v. 399 g/day). Compared with 8L: 16D, exposure to 16L: 8D non-significantly increased LW gain more in OVX heifers (16 kg) than in INT heifers (3 kg). Photoperiod did not significantly influence weight or composition of the carcass. There was no significant interaction between photoperiod and ovaries on carcass composition. Across all heifers GH declined (P < 0·05) and INS and PRL increased (P < 0·05) from day 64 to 138. Compared with 8L: 16D, exposure to 16L: 8D increased PRL on day 64 (P < 0·05; 13·4 v. 28·5 u.g/1) and decreased INS averaged across days 64 and 138 (P = 0·l; 0·71 v. 0·55 u/l) but had no effect on GH. GH, INS and PRL did not differ between INT and OVX heifers. It is concluded that ovariectomy of heifers reduces LW gains, carcass weights and accretion of protein, and that exposure to 16L: 8D partially prevents the loss in LW gain.
The effect of group size on the performance of growing pigs
Authors: Petherick J. Carol , Beattie A. W. , Bodero D. A. V. 
Published: September 2010

ABSTRACTThree replicates of three group sizes (six, 18 and 36) of grower pigs were housed with the same space allocation (0·66 m2per pig), feeding and drinking space per animal. The animals were mixed and kept together for a period of 22 days. They were given foodad libitum, were weighed weekly and a record kept of the group food intake for the 22-day period. Weight at mixing had a significant effect on weight gains during the 1st week. There was a significant interaction between group size and replicates for weight gains; generally weight gains were lowest in the group size of 36 animals during the first 2 weeks, but in the 3rd week there was no difference between the group sizes. Sex had no effect on weight gains. The variation in weights between group members were significantly greater in the group size of 36 than in the group sizes of six and 18 at the start of the trial, but at the end of the trial there was no difference in the variances of weights in the three group sizes. There was no difference between the group sizes in the variances of the weight gains. There was a significant positive correlation (r = +0·36) between weight at mixing and weight gain for the group size of 18. Group size had no effect on food intake, but the food conversion efficiency of the animals in the group size of 36 was significantly poorer than in the group sizes of six and 18.
Factors influencing the welfare and carcass and meat quality of pigs 2. Mixing unfamiliar pigs
Authors: Guise H. J. , Penny R. H. C. 
Published: September 2010

ABSTRACTMixing pigs from different social groups is known to cause turmoil which often results in skin lacerations as well as dark, firm and dry meat. Nine hundred and sixty commercial crossbred pigs were used for this experiment, divided into eight consignments. Within each consignment the pigs were divided into groups of about 15. The pigs in each group had coexisted for at least 6 weeks prior to slaughter. Thirty min before loading for slaughter, groups of pigs were either mixed with unfamiliar pigs or not mixed. Similarly, on arrival at the abattoir, groups of pigs were either mixed or not mixed. Hence there were four possible treatment combinations: pigs mixed with unfamiliar animals at loading, mixed at unloading, mixed at both points, or pigs which had remained in their social groups for at least 6 weeks prior to slaughter. Carcasses were dressed according to normal practice. After 20 h in the chiller room carcasses were assessed for skin blemish and fibre optic probe (FOP) values were measured in the longissimus dorsi muscle. Mixing pigs at either loading or unloading, or at both points, had no significant effect on the FOP value, but it did have a significant effect on the frequency of skin blemish values. Skin blemish values increased due to mixing at the farm (+0·36, Meat and Livestock Commission scale) however mixing at both places did not have an additive effect. The results indicate that the ideal movement system might be to keep pigs in their farm pen social groups until the point of slaughter.