bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentrations of blood constituents in genetically high and low milk-production lines of British Friesian and Jersey cattle around calving and in early lactation
Authors: Gibson J. P. , Field A. C. , Wiener G. 
Published: September 2010

ABSTRACTDifferences between Friesians and Jerseys and between progeny of high and low contemporary comparison (CC) sires were sought by examining nine blood constituent concentrations around first and second calvings and during lactation. A total of 1359 samples from animals at first lactation and 1148 samples at second lactation were collected. All animals were individually fed a complete pelleted dietad libitum. Blood constituents analysed were free fatty acids (FFA), ketones, glucose, calcium, magnesium, copper, phosphorus, albumin and globulin. All nine constituents showed marked changes around parturition and early lactation and several constituents showed changes with age. Jerseys had higher average copper and albumin levels and lower globulin levels than Friesians at both lactations and higher FFA concentrations at second lactation. Changes in plasma concentrations of FFA, ketones and glucose around calving were consistent in suggesting that Jerseys and progeny of high CC sires had a substantially greater energy deficit in early lactation than Friesians and progeny of low CC sires at the first but not the second lactation. Predicted requirementsv. recorded intakes suggested that the Jerseys and high CC progeny had the greater energy deficit at both lactations. Although the incidence of hypocalcaemia was nearly zero, changes of calcium and magnesium concentrations were consistent with reports of Jerseys being more susceptible to hypocalcaemia in later life.Despite large differences in milk yield, differences in plasma concentrations between animals classified as either high or low achieved yielders within their genetic class were generally smaller than differences between progeny of high and low CC sires.
Adrenal function in lambs treated with androgenic and oestrogenic growth stimulants
Authors: Sillence M. N. , Thomas K. M. , Anil H. , Redfern E. J. , Rodway R. G. 
Published: September 2010

ABSTRACTThree experiments were carried out in which plasma cortisol concentrations were measured hourly in lambs treated with various anabolic steroids. In the first experiment, female lambs were implanted with trenbolone acetate (TBA) and plasma cortisol was measured for 24-h periods 4 weeks after implantation and 1 week after reimplantation. Plasma cortisol levels were unaltered 4 weeks after treatment, but were found to be significantly lower 1 week after retreatment. On this occasion, peak concentrations of cortisol after ACTH challenge were also reduced by TBA. In the second experiment, female lambs were implanted with a mixture of TBA and oestradiol and plasma cortisol measured 1 and 4 weeks later. Results were similar to the first experiment although the reduction in plasma cortisol was less. In the third experiment, castrated male lambs were implanted with either TBA, TBA plus oestradiol or a long-acting oestradiol implant. In this experiment, only oestradiol affected plasma cortisol levels, causing a large elevation. All three treatments stimulated growth. Measurement of bound and free cortisol concentration in the third experiment indicated that oestradiol treatment tended to increase the proportion of cortisol present in the free form.These results suggest that an inhibition of cortisol secretion may be important in the anabolic response of female sheep to TBA. In the male, however, cortisol concentrations are naturally lower and are not further reduced by TBA treatment.Plasma insulin concentrations were also measured in the castrated males. Neither TBA nor the combined implant altered insulin levels, but oestrogen treatment resulted in a small increase in insulin. The diurnal pattern of plasma insulin closely paralleled that of cortisol.
Oestrus synchronization and fertility in ewes: a comparison of three methods
Authors: Beck N. F. G. , Davies M. C. G. , Davies B. , Lees J. L. 
Published: September 2010

ABSTRACTTwo experiments were designed to test the efficacy of two different methods of administering prostglandin F2α-tham salt for oestrous synchronization in mature cyclic ewes maintained under normal husbandry conditions. The effect of these agents on ewe fertility and lambing performance was also assessed.A total of 180 Clun Forest ewes were used in this investigation conducted during the 1983 and 1984 breeding seasons. In the 1983 breeding season, 80% of ewes treated with a single injection of 20 mg prostaglandin F2α-tham salt were mated by fertile rams within a 3-day period, compared with 100% of ewes treated with progestagen pessaries or 23% of ewes treated with saline. Returns to service for the three groups were 23%, 3% and 16%, respectively. In 1984, a single injection of 20 mg prostaglandin F2α-tham salt resulted in oestrus synchronization in 73% of treated ewes, compared with 27% of saline-treated controls and 97% of ewes given two injections of prostaglandin F2α-tham salt, 11 days apart. Returns to service following these treatments were 36%, 6% and 20%, respectively. There was no difference between treatments in lambing performance.The results indicate that acceptable levels of oestrus synchronization and fertility can be obtained with a single injection of 20 mg prostaglandin F2α. Furthermore, two injections of 20 mg prostaglandin F2α given 11 days apart produce levels of synchronization of oestrus comparable to those previously obtained with commercially available progestagen pessaries.
Livestock production in central Mali: environmental factors affecting weight in traditionally managed goats and sheep
Authors: Wilson R. T. 
Published: September 2010

ABSTRACTA study of the factors affecting weight in traditionally managed goats and sheep in central Mali was undertaken during 1978–84. Sheep were heavier than goats at all ages. Birth weights of goats (2·2 kg) were significantly affected by year and season of birth, parity, type of birth, sex and system (rain-fed millet or irrigated rice). Lamb birth weights (2·9 kg) were affected by all these sources of variation except year. System did not exert a significant influence on kid weights at 30 (4·3 kg), 90 (7·5 kg) or 150 days (10·5 kg) but the random effects of flocks and dams and the fixed effects of season, year, parity, type of birth, sex and the interaction of season × year were all significant at all three ages except for year at 30 days. Lamb weights (5·7, 11·1 and 15·5 kg) were significantly affected at all three ages by all sources of variation except season × year effects at 90 and 150 days. Repeatabilities of lamb weights were higher than of kids, probably due to milk being taken for human consumption from goats. There were few significant effects at post weaning to 730 days except those related to sex. Post-partum weights of goats (26·0 kg) were not affected by system, by the type of parturition nor by the sex of the young but were affected by season and year of parturition and by parity. Ewe post-partum weights (30·6 kg) were affected only by system and parity. Changes in weight over the year, pooled for 7 years, in specific age and sex groups averaged proportionately about 005 above and below the annual mean. Weights of mature animals were about 0·05 lower in 1984 than in 1978. Seasonal and long-term effects on weight are much less marked in small ruminants than in cattle under the same management system in the central Mali environment and the allocation of future research effort should take into consideration the relative advantages of the two types of stock.
The use of product traits such as lean growth rate as selection criteria in animal breeding
Authors: Simm G. , Smith C. , Thompson R. 
Published: September 2010

ABSTRACTIn meat animals there is some interest in lean growth rate or lean food conversion efficiency as selection criteria. These traits may be estimated as the product of growth rate (or efficiency), killing-out proportion and carcass lean proportion. When used as selection criteria these product traits do not require estimates of genetic parameters or economic values for component traits. Hence, they may be more stable, and of longer-term use than classical economic selection indices. The purpose of this study is to compare expected responses to selection on product traits with expected responses from selection, either on individual component traits, or on an economic selection index. Formulae were derived for predicting the phenotypic and genetic correlations between a product and one component, and for predicting the heritability of the product trait; these depend on the coefficients of variation and heritabilities of components, and on the genetic correlations among them. When the coefficient of variation of one component is much higher than that of the other, (× 3), this component will tend to dominate the product trait. In cattle and sheep, and to a lesser extent in pigs, killing-out proportion and leanness are usually less variable than growth rate or efficiency. Thus, in many cases, there is little loss in response in lean growth (or lean efficiency) from selection solely on growth rate (or efficiency) regardless of leanness. Although product traits do not require derivation of economic values, their component traits do have implied economic values. Often more appropriate weightings will be given to components by using an economic selection index, even when economic values and genetic parameters are not estimated precisely.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight 5. Adipocyte volume and number in the dissected fat partitions
Authors: Thompson J. M. , Butterfield R. M. , Reddacliff K. J. 
Published: September 2010

ABSTRACTThe cellular characteristics of dissected carcass (subcutaneous and intermuscular fat) and non-carcass (kidney fat, omental and mesenteric fat) fat partitions were examined at maturity in a total of 34 rams and ewes from flocks of Peppin Merino sheep selected for high (weight-plus) or low (weight-minus) weaning weight and from a randomly bred control flock. Strain and sex effects on the rate of change in adipocyte volume in each fat partition relative to the change in chemical-fat weight in that partition, were examined in 60 immature animals.Selection for high or low weaning weight had no effect on adipocyte volume in the mature animals, with the increased weight of fat in the weight-plus animals due to an increased number of adipocytes in the dissected fat partitions. Consequently, hyperplasia had a greater contribution to increases in chemical-fat weight in the weight-plus, compared with the weight-minus animals.Mature ewes had larger and fewer adipocytes in the subcutaneous and intermuscular partitions than the mature rams, whereas there was no difference between the sexes in adipocyte volume in the kidney, omental and mesenteric fat partitions. Mature ewes had fewer adipocytes than the mature rams in the subcutaneous, intermuscular, omental and mesenteric fat partitions. With the exception of the kidney fat partition, there was no sex effect on the relative contribution of hypertrophy to increases in chemical-fat weight of the dissected carcass and non-carcass fat partitions.
Protein growth in pigs
Authors: Whittemore C. T. , Tullis J. B. , Emmans G. C. 
Published: September 2010

ABSTRACTEstimates were made of total body protein in 45 unimproved crossbred pigs slaughtered serially between 20 and 200 kg live weight. Allometric functions were used to estimate protein weight at any given body weight and the Gompertz function was used to express live-weight changes in relation to time and to predict weight at maturity. Predicted values for daily protein retention increased rapidly from 20 kg to attain, at around 75 kg live weight, maxima of 130 g for entire males, 120 g for females and 105 g for castrated males. Between 45 and 110 kg live weight rates of protein retention were maintained within 10 g of the maximum rate. Mature live weights were estimated to be 240, 215 and 225 kg for entire males, females and castrated males. The allometric exponents for whole body protein as a function of body weight were 0·963 (s.e. 0·025), 0·927 (s.e. 0·021) and 0·850 (s.e. 0·049) for entire males, females and castrated males respectively.
Expectation and variance of genetic gain in open and closed nucleus and progeny testing schemes
Authors: Meuwissen T. H. E. 
Published: September 2010

AbstractOpen and closed nucleus and conventional and modern progeny testing schemes were compared for expectation and variance of genetic gain. Generation intervals were optimized, with minimum values of 2 and 6 years (progeny test results available) for males in nucleus and progeny testing schemes, respectively. Females had a minimum generation interval of 2 years, except in the conventional progeny testing schemes, which had a minimum of 4 years (one individual record available). Apart from the generation intervals and the progeny test, open nucleus and progeny testing schemes were identical, since ‘nucleus females’ are also born in progeny testing schemes, being full-sibs of the young bulls and dispersed over commercial herds. The number of nucleus sires (bull sires) selected was varied between four and 32. Selection was for milk production.A deterministic model was used, that accounted for variance reduction due to selection and the effects of finite size and family structure on the selection differentials. Prediction of the variance of the selection response accounted for selection of full- and paternal half-sibs.Closed nucleus schemes gave a factor 0·03, 0·13 and 0·19 larger response rates than open nucleus and modern and conventional progeny testing schemes, respectively. Reduction of genetic variance of open nucleus schemes was larger than that of closed nucleus schemes, which caused the slightly higher response rates of closed nucleus schemes. Standard deviations of selection responses of closed nucleus schemes were a factor 0·46, 0·79 and 0·86 larger, respectively.Preference for the schemes was assessed using a quadratic utility function expressing risk and inbreeding aversion. The increase in genetic gain due to shortening of generation intervals more than compensated for its increased variance. Whether the increased genetic gain due to closing the nucleus compensated for its increased variance depended on the amount of risk aversion. Selection of four sires and eight to 16 sires had the highest utility in progeny testing and nucleus schemes, respectively.
The effect of method of forage conservation and harvest season on the rumen degradation of forages harvested from permanent mountain meadows
Authors: López S. , Carro M. D. , González J. S. , Ovejero F. J. 
Published: September 2010

AbstractAn irrigated permanent mountain meadow (Leon, Spain) was cut twice in 1987, in late June, and again in early September after the summer regrowth. Herbage harvested from each season was preserved by different methods, namely freezing (fresh), ensiling in plastic bags (silage) and sun-curing (hay). Rumen degradation characteristics were determined by the nylon bag technique. Forages harvested in September had a higher crude protein (CP) concentration (153 v. 104 g/kg dry matter (DM)) and a lower cell wall concentration (467 v. 599 g/kg DM) than those from the June cut, resulting in a greater DM potential degradability (0·856 v. 0·751) and a faster degradation rate (0·088 v. 0·057 per h). Method of conservation did not affect the CP concentration of the forages, but had a significant effect on their nitrogen (N) solubility and protein degradability. Hay had the lowest N solubility (0·388) and CP degradability. Ensiling led to an increase in the N solubility (0·668 v. 0·554) compared with the fresh control, resulting in a higher effective degradability of CP estimated for different rates of passage. Forage conservation caused a slight increase in the relative proportion of the cell wall in the total DM (mean neutral-detergent fibre concentrations for fresh forage, hay and silage were 510, 548 and 536 g/kg DM, respectively) presumably due to loss of cell contents. Potential DM degradabilities of fresh forage, hay and silage were similar (0·805, 0·813 and 0·791 respectively). Although hay seemed to be degraded to a greater extent and at a faster rate than the other two types of forages, the rumen degradation characteristics were not consistently affected by the method of conservation to an extent that could have important nutritional implications.
Some effects of housing on the social behaviour of dairy cows
Authors: Miller K. , Wood-Gush D. G. M. 
Published: September 2010

AbstractA herd of high-yielding Friesian dairy cows was observed outdoors and in a modern cubicle house. Indoors there was a much higher level of gross agonistic behaviour than at pasture (9·5 v. 1·1 per h). Furthermore, the use of continuous filming showed a high level of avoidance amongst the cows which impeded the movement of the more submissive cows. All cows spent proportionately 0·34 to 0·56 of their time indoors watching one another and 0·45 to 0·66 of their time in ‘social tension’. There was less synchrony of behaviour indoors than at pasture and despite the presence of one Calan Broadbent stall for each cow there was a high rate of displacement from the stalls involving cows of all degrees of dominance. The results are discussed in relation to housing design and husbandry practice.
Dairy herd life in relation to linear type traits and production 1. Phenotypic and genetic analyses in pedigree type classified herds
Authors: Brotherstone S. , Hill W. G. 
Published: September 2010

AbstractThe relation between survival to complete lactations 2, 3 and 4 and both linear type and production traits of pedigree Holstein-Friesian dairy cattle in the United Kingdom was analysed. There were records on 23 071 pedigree animals which were themselves type classified as heifers. The linear and quadratic phenotypic regressions of survival on most type traits were significant, even with yield fitted as a covariate. Phenotypic regressions of survival on milk, fat and protein yield were significantly positive, but that on protein content significantly negative. Phenotypic correlations with survival were under 0·1 for the linear traits, 0·16 for a subjective total type score, and 0·14 for milk yield. Genetic correlations between survival and type traits, estimated by multivariate restricted maximum likelihood, were as high as 0·4 for several traits of the udder and teats and for total score, and higher than for milk yield or composition. Regressions of survival on estimated sire transmitting abilities gave rather lower estimates of genetic correlations, except for total score. The results indicate that in these pedigree and classifying herds the total score is a culling criterion in its own right.
Dairy herd life in relation to linear type traits and production 2. Genetic analyses for pedigree and non-pedigree cows
Authors: Brotherstone S. , Hill W. G. 
Published: September 2010

AbstractThe relation between linear type traits and survival to complete lactations 2, 3 and 4 of pedigree and non-pedigree Holstein-Friesian dairy cattle in the United Kingdom was analysed. Regressions of survival on sire transmitting abilities for type, i.e. estimates of genetic regression, were obtained for different data sets, either pedigree or non-pedigree offspring of sires whose progeny had linear type assessments made by either the Holstein Friesian Society or the Milk Marketing Board, thereby spanning different segments of the cattle population. Results were not completely consistent either over lactations or over data sets. In general, however, there was a significant positive association between survival and angularity, fore udder attachment and udder depth scores, and a negative association with chest width, rump width, and teat length. Regressions on yield were positive, while those on fat and protein content were usually negative. Survival in the herd can be predicted, although not with high accuracy, using type traits.
The performance and body composition of young pigs following a period of growth retardation by food restriction
Authors: Stamatarist C. , Kyriazakis I. , Emmans G. C. 
Published: September 2010

AbstractPigs were fed either ad libitum or given 300 g/day of the same food (digestible energy 15·4M)/kg; crude protein 208 g/kg fresh food) from 6 to 12 kg live weight (LW). Four pigs were killed at 6 kg LWand eight (equal numbers from the two sexes) from each treatment at 12 kg LW. Eight pigs (three males and five females; AL) were continued on ad libitum feeding to 24 kg LW when they were killed. Ten (four males and six females; R) of the pigs which had been restricted to 12 kg LW, were fed ad libitum to 24 kg LW, when they were killed. The entire empty bodies of the pigs killed were chemically analysed and the weights of organs determined. The empty body was considered as three fractions: the entire skin, including the subcutaneous fat (SK); the internal organs and the empty gastrointestinal tract (INT) and the remainder (CARC). The distributions of the chemical components between these three fractions were determined.The R pigs took 19 days longer and 2·6 kg more food to go from 6 to 12 kg LW. At 12 kg LWthey had less gut fill, lighter organs concerned with food processing and less lipid, more protein and heavier CARC weights than the AL pigs. The R pigs took 5·5 days less and 2·4 kg less food to go from 12 to 24 kg than the AL pigs. At 24 kg LW they had more gut fill, similar weights of the organs concerned with food processing, and slightly less lipid and protein. Over the 12 to 24 kg weight interval the R pigs gained lipid and protein at faster rates than the AL pigs. None of the increase in protein growth rate was in the CARC fraction.It is concluded that pigs given a low intake of food adjust their organ weights to be sufficient to process the allowance. On being given ad libitum food they rapidly increase the weights of their organs to process the increased rate of intake, and increase their gut fill. These effects are seen as a short lived, greatly increased rate of LW gain. During rehabilitation lipid stores return to their normal level but carcass protein does not show an increased rate of growth.