bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lactational oestrus in the sow 4. Variation in the incidence and timing of lactational oestrus in groups of sows
Authors: Bryant M. J. , Palmer G. , Petherick D. J. , Rowlinson P. 
Published: September 2010

ABSTRACTEighty multiparous Camborough hybrid female pigs (sows) and their litters, on average 15 days post partum, were housed in groups of five in multi-accommodation pens. The sows were fed ad libitum on a proprietary diet containing 160 g crude protein per kg from grouping to 30 days post partum, when they were fed to scale twice daily in individual feeders until weaning at 42 days post partum. One of four Large White male pigs (boars) was introduced to each group on the day following grouping, each boar being run with four groups.Oestrus occurred in 62 sows, on average 10·2 ± 3·3 days after grouping. The differences between groups in the interval from grouping and boar introduction to the onset of oestrus were statistically significant (P < 0·01). Neither the incidence nor the timing of oestrus could be related to the identity of the boar.Regression analysis revealed relationships between a number of independent variables and the incidence and timing of lactational oestrus. Sows which gained more live weight from farrowing to weaning and whose litters consumed more creep food were more likely to show lactational oestrus. Sows were slower to show lactational oestrus when they gained little weight from farrowing to weaning, had lower live weights at weaning and gained less weight from the previous weaning, despite eating comparatively more food during grouping. The sows which took longer to show lactational oestrus also had heavier piglets at grouping and more piglets in their litters at weaning. The difficulties arising in the interpretation of these results are discussed.
Food intake, growth and mature size in Australian Merino and Dorset horn sheep
Authors: Thompson J. M. , Parks J. R. 
Published: September 2010

ABSTRACTThe pattern of food intake as a function of age, and live weight as a function of food consumed was examined from soon after weaning to maturity in groups of fine and strong wool Merino rams and Dorset Horn rams and wethers. Each group, which initially comprised 20 sheep and from which individuals were removed for slaughter at approximately 6-kg increments in live weight, was fed a pelleted ration ad libitum for 98 and 77 weeks for the Merino and Dorset Horn groups respectively.The pattern of food intake was similar for all groups of sheep, in that food intake increased to a maximum at approximately 50 weeks of age and then declined with age with a regular oscillation superimposed on this curve. In all three groups of rams, but not in the Dorset Horn wethers, the oscillations in food intake were on an approximate annual cycle with a decrease in food intake in summer and an increase in winter.Estimated mature live weights for the strong and fine wool Merino rams were 120·5 and 97·6 kg, and for the Dorset Horn rams and wethers 108·6 and 101·4 kg. Variation between breeds in the level of food intake, food efficiency and consequently the pattern of growth, was largely a function of mature size. The Dorset Horn rams were slightly more efficient at converting food to live weight than the wethers.
The effect in an intensive production system of type of cereal and time of weaning on the performance of lambs
Authors: Ørskov E. R. , Fraser C. , Gill J. C. , Corse Elizabeth L. 
Published: September 2010

SUMMARYTwo experiments were conducted to study the effect of type of cereal and time of weaning on the performance and voluntary intake of lambs.In the first experiment 20 early-weaned entire male lambs were given diets ad libitum during the fattening period from 15 to 40 kg live weight. The diets were based on either kibbled maize or rolled barley. A high feed efficiency and growth rate were achieved with both diets and differences between them were not statistically significant. The growth rates were 428 and 430 g/day. The cold carcass weights at 40 kg live weight were 19·0 and 19·9 kg and the conversion ratios of dry matter to live-weight gain were 2·33 and 2·22 for the rolled barley and kibbled maize diets respectively.In the second experiment a comparison was made of the performance of 36 sets of twin lambs, one of each set being weaned at either 6, 13 or 20 weeks of age and the other being left to suck the ewe outdoors. The lambs weaned at 6 weeks had better conversions of dry matter to live-weight gain than lambs weaned at 13 and 20 weeks. The respective conversions of dry matter to live-weight gain were 3·36, 5·64 and 5·52. The lambs weaned at either 13 or 20 weeks had a greater weight at weaning, a greater growth check at weaning and a lower rate of feed intake.
Prenatal and postnatal competition among twin lambs
Authors: Burfening Peter J. 
Published: September 2010

SUMMARYTwin-born Rambouillet, Targhee and Columbia lambs were used to study the effect of sex of lamb and its co-twin on birth weight, weight at 60 days of age and weaning weight. Mean birth weights of female lambs were lower than those of males, and lambs born co-twin to males had a lower mean birth weight than those born co-twin to females. Lambs born co-twins to females grew faster from birth to 60 days of age and had a greater chance of surviving from birth to weaning than did lambs that were co-twins to males.
Design of experiments to estimate offspring-parent regression using selected parents
Authors: Hill W. G. , Thompson R. 
Published: September 2010

SUMMARYHeritability or the genetic regression of one trait on another, for example live-weight gain in field v. performance test station conditions, can be estimated efficiently by rearing offspring only from high- and low-ranking individuals, and estimating the regression of offspring on parent performance. Formulae are given for the optimum proportion of available animals to select as parents when the relative numbers of individuals in the parent and progeny generation are fixed. Although the optimum depends on the value of the parameter to be estimated, the designs are very robust to poor estimates.
Performance of sows first mated at puberty or second or third oestrus, and carcass assessment of once-bred gilts
Authors: MacPherson R. M. , Deb Hovell F. D. , Jones A. S. 
Published: September 2010

SUMMARY1. Of 80 gilts reared on a restricted plane of nutrition, 75 were allocated to one of four groups. Group 1; 17 gilts mated at puberty were slaughtered after farrowing their first litter. Group 2; 20 gilts mated at puberty were observed for three parities. Group 3; 18 gilts mated at second oestrus were observed for three parties. Group 4; 18 gilts mated at third oestrus were observed for three parities. Group 5; nine additional gilts reared on feed ad libitum and mated at first oestrus were observed for three parities. All animals received the same ration after the first mating.2. The mean age (±SD) of the restricted gilts at puberty was 186 ± 17 days at a weight of 89 ± 9 kg. The gilts fed ad libitum were significantly (P<0·01) older and heavier at puberty (203 ± 15 days and 120 ± 27 kg).3. Conception rates were 83, 86, 94 and 82% for Groups 1 and 2 combined, 3, 4 and 5 respectively.4. Gilts mated at first, second and third oestrus produced, respectively, 7·8, 9·8 and 10·4 ± 2·2 piglets in the first parity. Group 5 gilts had 11·0 ± 2·2 piglets. All significant differences were confined to the first parity.5. By the end of the third parity there were no differences between the restricted gilts mated at first, second or third oestrus in total number of piglets born or reared.6. The gilts slaughtered (at 135 kg) after producing one litter yielded carcasses which were heavier but leaner than those from contemporary maiden gilts grown to 120 kg on a semi-restricted feeding scale.
Fertility in Cheviot ewes. 2. The effect of level of pre-mating nutrition on ovulation rate and early embryo mortality in North and South Country Cheviot ewes in moderately-good condition at mating
Authors: Gunn R. G. , Doney J. M. , Smith W. F. 
Published: September 2010

ABSTRACTIn two experiments over 2 years, 57 North Country Cheviot and 82 South Country Cheviot hill ewes were differentially group-fed indoors over a 2-month period to achieve either good or moderate body con- dition. Over 5 weeks prior to mating, ewes in good condition were brought down in condition by restricted feeding and ewes in mod- erate condition were raised in condition by a high level of feeding. The ewes were thus in moderately-good condition at mating. After mating, ewes were maintained in this condition until killed either on return to service or at 29 ± 8 days for counts of corpora lutea and viable embryos.Ovulation rate in each breed was positively related to the level of pre-mating food intake at the condition level studied. Embryo mortality, as ova loss, was not influenced overall by the level of pre-mating food intake but loss of multiple-shed ova was greater than that of single-shed ova in ewes which had been on restricted feeding before mating. Although a greater proportion of ewes in the North Country Cheviot breed were not pregnant at slaughter, this could not be identified as a breed difference since the breeds were studied in different years.
A note on supplements for dairy cows offered silage of high digestibility
Authors: Castle M. E. , Retter W. C. , Metcalfe J. D. 
Published: September 2010

SUMMARYGrass silage with a dry-matter content of 20·7%, and containing 18·9% crude protein and 67·0% digestible organic matter in the dry matter was self-fed to 20 lactating dairy cows for 18 weeks. In addition, 9 kg of brewers' grains with a dry-matter content of 28·8% was offered to each cow daily. The two supplement treatments were a barley mix and a groundnut cube containing 11·9 and 33·5% crude protein in the dry matter respectively. The barley was given at the rate of 4 kg/10 kg milk, and the groundnut at 1·5 kg/10 kg milk. The mean daily yields of milk were 18·9 and 19·4 kg/cow on the barley and groundnut treatments respectively and did not differ significantly.
The nutrition of the veal calf 6. The effect of ultra-high (68 per cent) fat milk powders added to liquid skim milk, and a comparison with spray-dried skim milk powder containing 20 per cent margarine fat
Authors: Roy J. H. B. , Stobo I. J. F. , Gaston Helen J. , Shotton Susan M. , Ganderton P. 
Published: September 2010

SUMMARY1. Fifty-one Jersey, Ayrshire and British Friesian male calves were reared from birth to veal weights on one of three liquid diets.2. Two ultra-high fat milk powders containing 680 g fat, either beef tallow (T) or a mixture of coconut oil and beef tallow (CT)/kg dry matter were prepared and mixed with liquid skim milk (35 g powder/kg) to give diets TLS and CTLS, containing 200 g fat/kg dry matter. A third diet consisted of reconstituted spray-dried skim milk powder containing 200 g margarine fat/kg (MDS).3. The incidence of diarrhoea and of nasal discharge for all breeds, and of a high rectal temperature for the Ayrshire breed was greatest for calves given diet MDS and lowest for those given diet TLS. The incidence of lung lesions at slaughter was 100, 72 and 57% for the Jersey, Friesian and Ayrshire breeds respectively. Severity of lung lesions was lowest for calves given diet TLS.4. Dry-matter intake and live-weight gain, especially for the Ayrshire breed, were greater for calves given diets containing liquid skim milk and the ultra-high fat powders (TLS and CTLS).5. Fat digestibility was lowest on diet TLS. Protein digestibility increased with age. Digestibility of dry matter and lactose, and absorption of ash and calcium decreased with age. Calcium and N retention were lowest on diet MDS.6. Killing-out percentage was highest for the Friesian and lowest for the Jersey breed. Perirenal fat deposition was highest for the Jersey and lowest for the Ayrshire breed. Skin weight/kg0·73was higher for the Ayrshire calves than for the other two breeds.
Selection in a population with overlapping generations
Authors: Bichard Maurice , Pease A. H. R. , Swales P. H. , Özkütük K. 
Published: September 2010

SUMMARYA theoretical investigation is reported into the effects of overlapping generations on the prediction of genetic gain from repeated within-population truncation selection for a quantitative trait. The gain resulting from the selection process produces genetic differences between the groups of breeding animals of different ages, and between the means of their progeny. These differences are not allowed for in the usual prediction formula. The correct allowances to make for the genetic effects of maternal age are derived for a simple situation. The implications of these allowances on the overall rate of genetic progress, and on the optimum age structure for maximum progress, are shown in a model pig breeding programme. The normal prediction formula underestimates the genetic gain which can be achieved if females are kept for five litters by 10 to 12%, and overestimates the disadvantages of keeping females for more than one or two litters.
The performance of early-weaned calves offered concentrates or artificially dried grasses
Authors: Marsh R. 
Published: September 2010

SUMMARYIn two experiments dried grass cobs or concentrate were offered to calves for 20 weeks after weaning. In Experiment 1 the grasses were harvested in the autumn and in Experiment 2 in the spring. Within each experiment three grasses differing in quality and two levels of concentrate were compared.Dry-matter intake of the dried grasses highest in digestibility was lower than that of medium digestibility grass, and hardness of package, palatability and mould infestation were implicated as possible causal factors.Live-weight gains by calves were closely correlated with digestible organic matter (DOM) intake. There was no significant difference between spring harvested grasses and concentrate in efficiency of utilization of DOM for live-weight gain but autumn grasses were used less efficiently than concentrate. At similar rates of gain the replacement value (dry-matter basis) of dried grass for concentrate averaged 142: 1.
Comparative digestibility experiments with growing pigs and adult sows
Authors: Fernández J. A. , Jørgensen H. , Just A. 
Published: September 2010

ABSTRACTThe digestive ability of growing pigs and large adult sows was compared in digestibility experiments with 26 foodstuffs and diets. In all cases, the sows showed superior digestibility of nutrients. On average, the sows digested 150 g more crude protein, 100 g more crude fat, 300 g more crude fibre per kg diet and proportionately 0·09 more gross energy than the young animals. The superior ability of the sows to digest gross energy was negatively correlated with the soluble carbohydrate and gross energy concentration of the food. A close linear relationship between digestibility in growing pigs and that in sows was found, making it possible to apply digestibility data for growing pigs in practical diet formulation for sows.
Circadian variation in composition of duodenal and ileal digesta from pigs fitted with T-cannulas
Authors: Graham H. , Åman P. 
Published: September 2010

ABSTRACTCircadian variation in the composition of digesta was examined in pigs fitted with replaceable T-cannulas in the proximal duodenum and terminal ileum. The pigs were fed twice daily with a cereal-based diet containing Cr2O3, as a marker. Digesta were collected hourly for 16 h following morning feeding (pig live weight (LW) 25 and 65 kg) or as a 12-h composite collection (pig LW 45 kg), and analysed for pH, dry matter (DM), ash, crude fat, crude protein, starch, neutral-detergent fibre (NDF) and Cr2O3,.No statistically significant differences were found in the composition of digesta from pigs weighing 25 or 65 kg LW. Calculated relative to Cr2O3, recoveries in 12-h composite samples of duodenal and (ileal) digesta were 1·19 (0·34) for DM, 1·28 (0·31) for crude protein, 0·97 (0·05) for starch and 0·93 (0·79) for NDF. Composition of both duodenal and ileal digesta varied considerably during the sampling period and was particularly influenced by giving food. Between-hour coefficients of variation for the samples taken hourly were, in general, greater at the duodenum (mean 017) than at the ileum (mean 0·11), while mean within-hour (between pigs) coefficients of variation (0·19 and 0·18, respectively) were greater than those between hours. The Cr2O3 marker generally followed the flow of dietary matter through the gastrointestinal tract, although there was an indication of a partial separation of NDF from other dietary components in the stomach. Composition of the 12-h composite samples of digesta did not differ from that of the mean of the samples taken hourly for 16 h.
Relationships between whole-body chemical composition, physically dissected carcass parts and backfat measurements in pigs
Authors: Rook A. J. , Ellis M. , Whittemore C. T. , Phillips P. 
Published: September 2010

ABSTRACTLog-linear relationships between various measurements of the chemical and physical body composition of the pig were obtained in four datasets representing a range of sexes, genotypes and feeding treatments. One of these datasets (dataset 1) comprised genetic control and selection line Large White pigs. There were significant differences between datasets for most of the relationships investigated. The causes of the differences cannot be determined. Within datasets, relationships between various body components and the weight of crude protein in the whole body were unaffected by genotype or sex. The relationships of both intermuscular fat and trimmed carcass lipid with whole body lipid differed significantly between the control and selection lines in dataset 1. Fat thickness measurements taken over the m. longissimus at the last rib were less at the same body lipid in the selection line than the control line suggesting a redistribution of fat away from this area as a result of selection. Relationships between viscera, lungs and empty body weight were significantly affected by line while those between trimmed carcass, liver, kidneys and empty body weight were significantly affected by sex. Selection line pigs had less perinephric and retroperitoneal fat than controls at the same whole body fat weight and less subcutaneous fat at the same cold carcass weight. There were no significant line effects on lean or bone weight distribution. Selection line pigs had significantly less subcutaneous fat in the collar joint and more intermuscular fat in the ham. There were few significant sex effects on tissue weight distribution.
The value of indicator traits in the genetic improvement of dairy cattle
Authors: Woolliams J. A. , Smith C. 
Published: September 2010

ABSTRACTThe value of indicator traits (7), such as physiological or biochemical traits in the genetic improvement of dairy cattle for milk yield (M) was studied. First, some corrections were made to the base rates of genetic change possible by improvement systems based on progeny testing and on multiple ovulation and embryo transfer (MOET), and on combinations of these. Efficient field progeny-testing systems can be competitive with current adult MOET nucleus herd schemes but juvenile MOET nucleus herd schemes offer substantial increases in rates of response. With high co-heritability, selection for the T alone may allow greater rates of response than those currently considered feasible using progeny testing. However, faster rates are obtained with combined selection. When breeding values are accurately measured by pedigree and performance records on M, as in the progeny test, the extra rates of response with combined selection may be small. Where breeding values are less accurately assessed, as in juvenile MOET nucleus schemes, the extra rates of response can be appreciable. For T with co-heritability (hMrGhT) of 0·27 and the CV for M from 0·15 to 0·20, response rates of 2·0 to 2·7% of the mean per year possible by traditional methods could be increased to 2·2 to 2·9% in progeny testing schemes, 2·3 to 3·1% and to 4·3 to 5·7% for adult and juvenile MOET nucleus schemes respectively.A possible useful indicator trait is blood urea nitrogen (BUN) measured in young animals after a short fast. Results from four experiments with calves having high or low genetic merit for M were summarized. The pooled co-heritability estimate was —0·27 (s.e. 0·05). With this, or even a more modest effect, BUN would be a useful indicator trait in selection for milk production. Its use in practice in high and low selection lines or in a section of the industry, would allow assessment of the merit of the method.
Accuracy and consistency of prediction of pig carcass lean concentration from P2 fat thickness and sample joint dissection
Authors: Planella J. , Cook G. L. 
Published: September 2010

AbstractCommercial carcass grading measurements and sample joint dissection were evaluated as predictors of carcass lean concentration using a data set of 1320 pig carcasses from four breeding companies. Entire males, castrated males and gilts from White-type and Meat-type populations were reared on ad libitum or restricted feeding regimens and slaughtered to achieve a carcass weight of either 52·5 kg or 72·5 kg. A model was fitted which examined the accuracy and stability of regression equations for different populations, sexes and feeding regimens, and different values of P2 and carcass weight. The regression slope of lean concentration on P2 differed by sex and population. Lean concentration decreased faster with increases in P2 among gilts than among entire or castrated males. At the same level of P2 and carcass weight, pigs fed ad libitum contained 5 g/kg less lean in the carcass than pigs fed at a restricted level. Biases among populations, sexes and feeding regimens were also found when carcass lean concentration was predicted from additional measurements: muscle depth at P2, fat thickness and muscle depth at 3/4 last ribs, and eye-muscle area. The regression slope of lean concentration on sample joints showed little evidence of variation among populations (except for the hand joint), sexes or feeding regimens. There were important differences in the intercept for different populations. The ham was the most accurate (residual s.d. = 11 g/kg) and least biased joint.