bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mortality among twin and single lambs
Authors: Purser A. F. , Young G. B. 
Published: September 2010

The effects of maternal age and birth weight on survival of twin lambs has been studied in a Blackface and a Welsh Mountain flock. The time of death was also investigated for both singles and twins.Twin mortality was higher than mortality of singles, mainly due to the lower average birth weight of twins. Twin mortality declined with increasing birth weight although it showed a tendency to increase at the top of the scale. Weight for weight, mortality was similar for singles and twins. Twin mortality declined with increasing age of ewe in a very similar pattern to single mortality.Lamb mortality was heavy at birth and during the first 14 days of life with only 30% of the mortality occurring after this age. Approximately 12% of the dead lambs were stillborn. Among singles a similar proportion died as a result of difficult births, but this cause of mortality was rare in twins.Stillbirth mortality rates were very high for very small birth weights and declined with increasing weight of lamb. Difficult births, on the other hand, increased with increasing birth weight. The association of birth weight with mortality was particularly important in the first 14 days of life but thereafter its significance was less.Although mortality in lambs of younger ewes was heavier than that of older ewes, similar causes of death operated. Younger ewes, however, having lower birth weights tended to have more stillbirths but few losses due to difficult lambings.
A comparison of reciprocal progeny tests amongst Holstein-Friesian sires from Canada and the United States of America
Authors: Hinks C. J. M. , Zarnecki A. 
Published: September 2010

SUMMARYThe test proofs of 29 Holstein-Friesian sires (12 Canadian and 17 US) with milking daughters in both Canada and the USA were compared. The mean test rating of the Canadian and US sires respectively was 125±74 kg and 265±57 kg higher in Canada than in the United States.These results were supported by others obtained in milking trials in Denmark and West Germany.The fat percentage of US Holstein progeny was higher in Canada and Europe than in the USA, suggesting that the low fat percentage of the US Holstein in its country of origin cannot be attributed simply to lack of genetic potential.It is suggested that the US Holstein be considered as a substitute for the Canadian for the improvement of milking performance in European Friesian populations.
Factors affecting birth weight of Santa Gertrudis calves
Authors: Willis M. B. , Wilson A. 
Published: September 2010

SUMMARYBirth weights of 568 Santa Gertrudis calves by 15 sires out of 111 different dams over a 14-year period were obtained from a herd in Cuba. Year of birth, season of birth, sex of calf, sire and dam all had highly significant influences upon birth weight but there was no effect of dam age or parity. Calf inbreeding ranged from 0 to 25% and led to a decrease of 012 kg in weight for each 1% increase in inbreeding. Calves surviving to weaning or dying between birth and weaning were of similar mean weight. Calves dying at birth were some 4·53 kg above the overall average of 38·59 kg. Sire effects covered a range of some 9·85 kg in birth weight. Heritability of birth weight estimated from an intra-class correlation between paternal half-sib groups was 0·67. Repeatability estimates were of the order of 0·22 from intra-class correlation and 0-24 on the basis of regression of later on earlier records. The overall least squares mean weight of 38-59 kg was several kg higher than previous estimates in the literature.
Comparative studies on the effects of feeding different types of oils at two levels on the performance and carcass characteristics of growing pigs in the tropics
Authors: Babatunde G. M. , Fetuga B. L. , Oyenuga V. A. 
Published: September 2010

SUMMARYTwo feeding trials involving 105 pigs weighing approximately 14·5 kg were carried out to investigate the effects of palm oil, groundnut oil, locally produced lard, and beef tallow at 2·5% and 5% of the diet, on performance characteristics and carcass quality. The pigs were of the Yorkshire and Yorkshire × Landrace crosses, and of both sexes. The 23% protein basal diet had no oil added, and the other eight diets were made from the basal diet by the weight-for-weight substitution of the maize with the 2·5% or 5% levels of the four oil types. The results of the two trials were combined and considered as a 2 × 4 factorial experiment (2 levels and 4 types of oil) with the basal diet serving as the control. Only the pigs in the second trial were slaughtered and their carcasses graded at the average live weight of 57±1 kg. Correlation and regression analyses were made on some performance and carcass characteristics, on the average daily digestible energy intake. Results showed no significant treatment differences in the average daily gains, average daily feed intake, and average daily digestible energy intake, but there were highly significant treatment differences in feed consumed/kg of gain and average digestible energy (DE) consumed/kg of gain (P<0·01). None of the carcass quality parameters showed any significant treatment differences. Both the correlation and the regression coefficients for the average daily gain on DE intake were highly significant for all the oil types and levels, but the relationships were low and non-significant when the feed/gain ratio, average backfat thickness and the average percentage of lean cuts were regressed on the daily DE intake.
A note on the heat production of fasting pigs in the range 16 to 96 kg live weight
Authors: Holmes C. W. , Breirem K. 
Published: September 2010

SUMMARYThe results of earlier work by Breirem have been reanalysed, and some recent results are presented. Breirem's results indicated that for pigs of 16 to 96 kg live weight and fasted for 4 to 9 days, heat production (HP) was related to live weight (LW) according to:HP = 229 LW0·512which could be converted to:HP = 185 LW0·569This equation gives values for fasting heat production which are about 20% higher than those usually estimated from Breirem's results on pigs of 16 to 196 kg. The recent results, for pigs fasted for 24 hr, were slightly higher than would be indicated by the latter equation. If the values derived from the reanalysis of Breirem's data are related to several estimates of the energy required for maintenance by pigs, values for km% between 87 to 103% are obtained.
Studies on the intake and utilization of wet feed by calves
Authors: Fitzgerald J. J. , Kay M. 
Published: September 2010

SUMMARYA latin square design with three periods of 3 weeks was used to measure the dry-matter intake, live-weight gain and water intake of 12 British Friesian calves offered an all-concentrate diet ad libitumin wet form. The diets contained 30% (B), 20% (C) or 15% (D) dry matter. A further six calves were given the same diet in dry form (A) throughout the experimental period. Digestibility and nitrogen balance were measured on four calves on each treatment at the end of the experimental period. In addition, two Ayrshire calves, each fitted with a permanent abomasal cannula, were used to study the site of digestion of the feed when given in dry or wet form.The mean dry-matter intakes of the calves given the dry and wet feeds were 75·5 and 80·8 g/kg W0·75 per day respectively and mean daily live-weight gains were 849 g for the calves on both types of feed. The mean dry-matter intakes of the calves given the wet diets were 80·9 (B), 81·2 (C) and 75·5 (D) g/kg W0·75 per day, and the live-weight gains (g/day) were 857 (B), 879 (C) and 812 (D). None of these differences were significant. The intake of water by the calves was significantly increased by reducing the dry-matter content of the diet. The form or dry-matter content of the diet offered had no effect on the digestibility of dry matter (76·1%), organic matter (77·9%), energy (75·8%) or crude protein (75·8%) or on nitrogen retention (32·5% of N intake).The rumen was the main site of digestion for all Tour diets and an average of only 7% of dietary starch passed undigested through the abomasum.
Model responses of the growing pig to the dietary intake of energy and protein
Authors: Whittemore C. T. , Fawcett R. H. 
Published: September 2010

SUMMARYA simple model is described which enables the prediction of the magnitude and direction of the responses of growing pigs to different energy and protein intakes. The model calculates daily live-weight gain from the conversion of the dietary supply of crude protein and energy into protein, lipid and ash in the body of the growing pig. Values were also determined for the energy and protein balances, the composition of the body and the efficiency of feed conversion. The model was formulated with factors drawn from published findings and validated by comparison with independent feeding trials.
Optimum replacement rates in animal breeding
Authors: Ollivier L. 
Published: September 2010

SUMMARYThe expected annual selection response is a function of selection intensity (i), generation interval (t) and precision (p) of breeding value estimation. These three parameters may, under certain conditions, be reduced to functions of one variable, y, the mean age of breeding animals at culling, which is a simple function of the annual replacement rate. When the number of breeding males and females are different, i and t become functions of two variables ym and yf, the mean ages of males and females at culling. The values of y (or of ym and yt) giving the maximum selection response are established for different domestic species: for individual selection, where the ratio i/t is to be maximized, for selection on a repeatable criterion connected to female reproduction (prolificacy, milk or egg production), where the maximum of ip/t is to be determined, and for male progeny-testing. The results show that, the more prolific a species is, the more rapid the renewal of breeding animals must be and that the renewal should be more rapid for males than for females, particularly in species of low prolificacy. When selecting on female performances which are repeated in time, the optimum renewal rate of females is lowered relative to individual selection on a criterion measured once. Numerical values have been calculated for different species, with given reproduction parameters for each one.
Some aspects of competition between sheep for supplementary feed
Authors: Arnold G. W. , Maller R. A. 
Published: September 2010

SUMMARYCompetition for oat grain between sheep grazing on scant, poor quality pasture was studied in three flocks of sheep. A daily feed of 450 g per head was fed in troughs with the space per sheep varying from 4 to > 50 cm. Records were taken of sheep behaviour during the first 3 min of feeding.There was no fighting in the competition for feed, but dominance of individuals and of groups of sheep occurred. With abundant trough space, certain sheep led the way to the feed trough and were termed leaders, but ‘leadership’ was a characteristic unrelated to competitiveness during feeding. With restricted trough space most sheep raced to the feed trough at feeding time. The rate of disturbance of the sheep from the feed trough increased with decreased space per sheep, particularly below 12 cm/sheep. As the rate of disturbance increased a progressively greater proportion of sheep stopped competing for feed and became non-feeders. Neither the rate of disturbance of the sheep nor the proportion not feeding was related to body weight, but these were largely individual characteristics of sheep.In a flock of mixed age Merino wethers, the 1-year-old and 7-yearold sheep were the least competitive, while in a flock of wether sheep of seven different breeds but of similar age, Merinos were least competitive.From these experiments it is suggested that a minimum trough space of 16 cm be allowed when daily grain supplements are fed to grazing sheep.
The effect of dietary crude protein concentration and time of weaning on milk production and body-weight change in the ewe
Authors: Robinson J. J. , Fraser C. , Gill J. C. , McHattie I. 
Published: September 2010

SUMMARYTwenty-seven North Country Cheviot ewes, each carrying twin foetuses and having a mean body weight at 6 weeks prior to parturition of 81 kg were individually penned and offered a constant daily intake of 16·75 MJ metabolizable energy during the last 6 weeks of gestation. At parturition the ewes were allocated to one of three dried grass/concentrate diets containing (1) 10·3, (2) 13·6 or (3) 16·9 % crude protein (CP) and 10 MJ metabolizable energy (ME) per kg. The mean daily CP intakes for diets 1 to 3 were 273, 340 and 415 g respectively and the mean daily ME intake was 25 MJ. Within each level of dietary CP intake the lambs were weaned at either 25, 35 or 41 days of age.There were no significant diet × stage of weaning interactions in milk yield or ewe body-weight change during lactation. The mean daily levels of milk production were 2·4, 2·9 and 3·1 kg for diets 1 to 3 respectively. The corresponding values for ewe body-weight loss were 118, 170 and 265 g per day. When the diet contained 13·8% CP the incremental increase in milk production per unit increase in protein intake was 4·2 g/g. This gave an incremental increase in lamb growth rate of 0·79 g/g and was equivalent to the associated incremental increase in ewe body-weight loss.A reduction in the concentration of CP in the ewes' diet when the lambs are 3 weeks of age may be a useful practical procedure for decreasing milk production and for reducing the body-weight loss of the ewe in a frequent breeding system.
The relationship in ewes between voluntary food intake during pregnancy and forage intake during lactation and after weaning
Authors: Foot Janet Z. , Russel A. J. F. 
Published: September 2010

ABSTRACT(1) Voluntary intake of forage was measured in 31 Scottish Blackface ewes for the last 14 weeks of pregnancy, throughout lactation, and 15 weeks subsequently. During pregnancy 15 ewes were given hay and 16 dried grass (apparent dry-matter digestibilities in vitro were 51 and 69·6% respectively). All ewes were given the same dried grass during lactation and after weaning (digestibilities 75 and 73% respectively). Body fat was estimated from tritiated water space.(2) Pregnant ewes consumed twice as much digestible dry matter from dried grass (1028 g) as from hay (502 g). Intakes of ewes with twin and single foetuses were similar.(3) During lactation the mean daily intakes of dried grass were 2278, 2610,2612 and 2722 g dry matter respectively, for ewes that had been given dried grass in pregnancy and had single and twin lambs, and for those that had been given hay and had singles and twins. Differences between dried grass and hay were consistently significant (P < 0·01).(4) After weaning the intakes declined rapidly but their ranking remained similar.(5) Lamb birth weights were affected by nutrition during pregnancy, lamb growth rates within twins or singles were not influenced by maternal nutrition during pregnancy or lactation. Differences in ewe intakes during lactation were reflected in ewe body-weight changes.(6) For all ewes, up to 64% of the variation in intake during lactation could be related to factors prevailing before and at lambing (pregnancy diet, ewe weight and fat content) and during lactation (lamb gain and ewe weight change).
A comparison of Canadian Holstein and British Friesian steers for the production of beef from an 18-month grass/cereal system
Authors: Cook K. N. , Newton Jennifer M. 
Published: September 2010

ABSTRACTThe trial compared 50 purebred Canadian Holstein and 46 British Friesian steers. The cattle were reared on a grass/cereal system designed to achieve an overall target live-weight gain of 0·82 kg per day from weaning to slaughter at 18 months of age. The cattle, born i n September 1973, grazed during the summer of 1974 and were slaughtered out of yards from January to July 1975. Equal numbers of each breed were allocated at random to three slaughter weights (477, 500 and 523 kg live weight). The Meat and Livestock Commission measured and classified all carcasses. In addition, a sample was cut according to commercial specifications. There were no significant differences in slaughter age or live-weight gain between the breeds. A significant difference (P < 0·05) in killing-out percentage was found in favour of the British Friesian as was a small (4%) but highly significant difference (P < 0·001) in carcass gain.The Canadian Holstein carcasses were considerably longer (P < 0·001) with less eye-muscle area (P < 0·001). The British Friesian carcasses contained 0·7% more saleable meat (P < 0·001) and 1% less bone (P < 0·01). There were no significant differences in fat trim. There were large differences in live appearance and carcass classifications, the British Friesians being of superior beef conformation.
A simple model of lactation curves for milk yield, food requirement and body weight
Authors: Wood P. D. P. 
Published: September 2010

ABSTRACTSimple algebraic models of milk yield, live-weight change and food requirement are developed for use in a programmable desk calculator. The unit of time used is a week and of energy a megajoule. An algebraic equation for milk production is used to define potential energy output. An expression using live-weight gain describes the demand for energy for the recovery of weight lost and the requirements of pregnancy. The use of appropriate conversion factors enables the necessary dietary input to be calculated. The model also takes account of restricted feeding by allocating dietary energy to milk production and live-weight gain in proportion to their potential demand. Ten decisions relating to milk yield, live-weight loss and live-weight gain are required by the model.
Genetic responses in the early years of selection programmes using genetic differences between generations
Authors: Hopkins I. R. , James J. W. 
Published: September 2010

ABSTRACTRecurrence relationships are used to relate breeding values of age-sex classes from different time periods. Their application to single-stage (progeny) and multi-stage (parent) selection is demonstrated. These relationships enable definition of the effect of age structure, initial genetic differences between age groups, and the extent to which allowances are made for these or later genetic differences between age groups. The expressions derived show that, given initial genetic differences between age groups, subsequent progeny means will fluctuate even under completely random selection. Using these means as a basis for measuring responses to selection, it is shown that there can be selective effects where selection is at random within parental age classes. A careful definition of the alternative programme is therefore important in interpreting results of selection experiments and in investment appraisal of selection programmes.These models were then used to describe economic returns from parent and progeny selection programmes and from programmes in which returns are realized in more than one age group. A further extension of the model accommodates the effects of finite population size on returns through its effects on genetic variance.By separating the (constant) within- and (fluctuating) between-group components of the selection differential within the recurrence relationships a number of computational problems are overcome.
A comparison of different predictors of the lean content of pig carcasses 2. Predictors for use in population studies and experiments
Authors: Evans D. G. , Kempster A. J. 
Published: September 2010

ABSTRACTLinear measurements and sample joint dissections were examined as predictors of carcass lean percentage using data from 1060 carcasses comprising 108 subgroups (nine genotypes × two sexes × two feeding regimes × three slaughter weights). The potential predictors were examined in terms of precision, cost and the stability of their regression equations.Probed fat thickness 6·5 cm from the dorsal mid-line at the last rib (P2) was the individual measurement giving the most precise prediction (residual s.d. pooled within subgroups = 2·21 percentage units; r = −0·72). The square root transformation (P2½) gave stable regression slopes over levels of all four factors, though there were important differences in intercepts between genotypes, sexes and slaughter weights.The precision of prediction from the lean percentage of sample joints was generally improved by including P2½ with each in multiple regression. Used in this way with current Meat and Livestock Commission costings, the ham joint offered the best compromise between cost and precision (pooled residual s.d. = 1·25 percentage units; R = 0·92). Regression slopes on each joint were stable for all factors except for those on the rump back and rib back joints which varied by feeding regime. Intercepts varied by genotypes for all joints except the ham, while intercept differences for feeding regimes were small or non-significant.The results confirm the value of the ‘sub-sampling with regression’ procedure for predicting carcass composition.
The flock-mating of progestagen-synchronized ewes 3. A note on the influence of flock size upon mating behaviour and lambing performance
Authors: Bryant M. J. 
Published: September 2010

ABSTRACTCrossbred ewes in which the oestrous cycles had been synchronized by the use of progestagen-impregnated vaginal sponges were mated with Suffolk rams either as a single group of 68 ewes (G) or as four subgroups of 17 ewes (S) in 2 years. Ram:ewe ratio was 1:17 in both treatments. G rams performed more mounts and services than S rams. Non-return rate and lambing rate was better for S than G ewes, especially in Year 1, when fewer G ewes were served. Mating activity was greater in Year 2 than Year 1; prolificacy was also markedly improved.
The performance of lambs reared by ewes given protected lipids during late pregnancy and early lactation
Authors: Steele W. 
Published: September 2010

ABSTRACT1. Two groups of ewes were given a dietary supplement containing 40 g of either ‘protected’ tallow (PT) with only 3% linoleic acid or ‘protected’ safflower oil (PP) with 57% linoleic acid for 28 days prepartum and 30 days post-partum.2. Although the birth weights of the lambs were unaffected by dietary treatment, the lambs in the PT group gained weight approximately 20% faster than those in the PP group.3. The gross compositions of the milks of both groups of ewes were similar but the milk fat obtained from the PP group contained about twice as much linoleic acid as was found in the PT group.4. Dietary treatments did not affect the haematocrits, red blood cell (RBC) or white blood cell numbers of the lambs. However, the haematocrits were higher at birth than at 10 days later and the RBCs were found to be less fragile at birth than at 10 days later.5. The ratio of trienoic/tetraenoic fatty acid in the plasma lipids of the lambs was positively correlated with live-weight gain. Male lambs grew faster than females and twins faster than triplets and the trienoic/tetraenoic ratio was higher in males than females and higher in twins than in triplets.6. These results showed that although it was possible to increase the linoleic acid content of the milk of ewes and of the blood lipids of their lambs by feeding protected safflower oil, no increase in lamb growth was obtained.