bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative performance and body composition of control and selection line large white pigs 2. Feeding to appetite for a fixed time
Authors: Ellis M. , Smith W. C. , Henderson Ruth , Whittemore C. T. , Laird R. 
Published: September 2010

ABSTRACTFood intake was individually measured for Large White control (C) and 10th generation index-selected (S) pigs fed twice daily to appetite on a fixed time trial. Thirty-nine C and 38 S boars were slaughtered, their carcasses dissected and whole empty bodies minced and chemically analysed after an 84-day trial starting at 28·6 ± 0·30 kg live weight. S boars ate proportionately 0·08 less than C boars in the first 42 days of the trial (79 v. 86 kg, P < 0·01), but S and C boars ate similar amounts (114 v. 117 kg, NS) in the last 42 days. S boars grew 0-04 faster than C boars (918 v. 886 g per day, NS), and had 0·09 better food conversion efficiency (0·404 v. 0·369 gain per kg food, P < 0·001). S boars contained more water than C boars (53·5 v. 48·9 kg, P < 0·001), more protein (15-4 v. 14-2 kg, P < 0·01), less lipid (20·8 v. 25·1 kg, P < 0·001), less gross energy (1 199 v. 1 357 MJ, P < 0·01) but a similar amount of ash. S carcasses had 3 kg more lean (36·5 v. 33·5 kg, P < 0·001) and more bone than C carcasses (7·14 v. 6·71 kg, P < 0·05), but contained 3 kg less total fat (19·6 v. 22·6 kg, P < 0·01). The lean tissue growth rate of S boars was 327 g per day which was 31 g per day faster than for C boars (P < 0·001). Appetite reduction in S boars enhanced fatness differences between the lines.
The influence of nutrition in early life on growth and development of the pig 1. Effects of protein nutrition prior and subsequent to 6·5 kg on growth and development to 45 kg
Authors: Campbell R. G. , Dunkin A. C. 
Published: September 2010

ABSTRACTForty-five piglets were used to study the effects of feeding diets containing 153, 239 or 321 g crude protein per kg dry matter between 1·8 and 6·5 kg live weight, and low and high protein diets subsequent to 6·5 kg live weight on growth performance, body composition and the cellularity of skeletal muscle to 45 kg live weight.Reducing dietary crude protein between 1·8 and 6·5 kg live weight depressed growth performance and at 6·5 kg live weight increased body fat content but reduced body protein, body water and the weight and DNA content of the adductor muscle. The effects of dietary protein content before 6·5 kg live weight on body composition at the latter weight were still evident in pigs killed at 11·5 kg live weight whilst the differences in muscle DNA persisted to 45 kg live weight.On the lower protein treatment subsequent to 6·5 kg live weight there was a tendency for pigs given the lowest protein diet before 6-5 kg live weight to exhibit better growth performance and deposit protein at a faster rate than those given the higher protein diets. However, these responses were reversed on the higher protein treatment subsequent to 6·5 kg live weight.The effects of dietary protein content subsequent to 6·5 kg live weight on growth performance, body composition and the cellularity of muscle tissue were qualitatively the same as those for the live-weight phase 1·8 to 6·5 kg.
Dissemination of genetic improvement through a livestock industry
Authors: Bichard Maurice 
Published: September 2010

SUMMARYA theoretical study is reported of the way in which additive genetic improvement, made in a nucleus population, is passed to successive levels in a three-tier multiplication system. The rate at which progress accumulates at each level is approximately equal. The extent to which each tier is genetically behind the previous one has been termed the ‘improvement lag’. These lags can be considerable; their actual size is determined by the annual rate of progress in the nucleus, the age structure in the lower tiers, and by the origins and degree of selection achieved in the animals used as parents in these tiers. Only improvements generated in the top tier are cumulative. The scope for reducing the improvement lag is discussed within the context of livestock production in Britain.
Selection of mice for growth on constant and on changing maize-milk diets
Authors: Bateman Nigel 
Published: September 2010

SUMMARYEffects of constant and of changing diets on responses to selection were studied. Mice were fed maize meal and dried skim milk from 3 to 5 weeks of age and were selected for live-weight gains in that period. Gains in the generation prior to selection were 17·7 g on 76% maize (24% milk), 8·0 g on 16% maize and 5·5 g on 100% maize.The Fixed optimum line was selected on 76% maize, the Milk line on 16% maize and the Maize line on 100% maize. The diets of three other lines were reviewed at each generation, and two diets were fed on each occasion. The diets of the Shifting optimum line straddled the optimum of the previous generation; those of the Milk-impelled line at first had a little more than the optimum amount of milk, but were made more milky as normal growth resumed; and the Maize-impelled line was similarly directed towards 100% maize. Back selected milk, optimum and maize sublines were taken off the three lines on constant diets. The Control line measured unimproved rates of growth on 16%, 52%, 76% and 100% maize.Dietary effects were not always repeatable. Controls on the optimum diet, 76% maize, were the most stable across generations and with this diet, gains generally had the lowest phenotypic variance within generations —g2. With 100% maize, this variance was slightly larger—8 g2. The diet with the least stable effect was 16% maize; as Control gains rose from 8 to 15 g, phenotypic variance fell from 21 to 6 g2. On various diets between 88% and 96% maize, the variance of the Maize-impelled line rose from 6 to 34 g2without commensurate changes in its mean gain.Responses of generally about 5 g above controls were made in five generations of selection. The Maize line was exceptional in making no forward response. Heritability of growth between forward and back selected sublines was highest on good diets (0·49 on 76% maize) and lower on poor diets (0·20 on 16% maize and 0·28 on 100% maize).The Fixed and Shifting optimum lines do not as yet differ on comparable diets; nor the Milk and Milk-impelled lines on 16% maize. The Maize-impelled line has not yet been tested on 100% maize and cannot be compared with the Maize line. Family-by-diet interactions were smaller than consistent family differences. It is concluded that genotypic improvements may be effective over a wide range of maize-milk diets.
The growth of young cattle fed on dried grass alone and with barley 2. Effects on digestion
Authors: Poutiainen E. K. , Lonsdale C. R. , Outen G. E. 
Published: September 2010

SUMMARY1. Young cattle were fed on four types of wafer containing chopped or coarsely-milled dried grass, with or without 50% of barley.2. At slaughter, the alimentary tract of each animal was removed and the contents of each part were weighed and sampled to determine the extent and site of digestion. Chromic oxide was used as an indigestible marker.3. The form in which the grass was processed had no effect on any of the parameters measured.4. The dry-matter content of the digesta in all parts of the alimentary tract was significantly higher when barley was included in the wafers. The inclusion of barley decreased the proportion of acetic acid and increased the proportion of butyric acid in the rumen liquor. The proportions of propionic and valeric acids were unaffected. Barley also appeared to reduce the proportion of digestible dry matter which disappeared in the forestomachs (31·44%) compared with that when grass was given alone (42·59%).5. With grass alone about 70% of the apparently digestible cellulose disappeared from the forestomachs, but the technique used did not allow a good estimation of these proportions when mixed diets were given. The retention time of dry matter in the forestomachs was not affected by the diet but the inclusion of barley in the wafers increased the retention time of cellulose in the forestomachs.6. Of 1·6·1·9 kg of starch ingested in mixed diets, 92-96% was apparently digested in the forestomachs, and only 80-130 g per day escaped rumen fermentation. The intake of starch on diets of grass alone was negligible and almost all the soluble sugars were digested in the forestomachs.7. More N was recovered at the omasum than was ingested, but the different diets had no effect on the site of digestion of N.
The distribution of chemical fat in the bodies of scottish blackface ewes
Authors: Russel A. J. F. , Doney J. M. , Gunn R. G. 
Published: September 2010

SUMMARYThe distribution of chemical fat throughout the major depots of the fleece-free empty body was studied in 30 mature Scottish Blackface ewes from two sources and covering a wide range of fatness.Relationships between amounts of chemical fat in individual depots and total body fat are presented. These provide information regarding rates of change in the distribution of fat with changing fatness. Information is also presented which allows estimates of the distribution of chemical fat throughout the body to be made from subjectively assessed condition scores.
Nutrition of the early-weaned calf. XII. The effect of diets differing in physical form on feed intake and rate of gain
Authors: Kay M. , MacLeod N. A. , Andrews R. P. 
Published: September 2010

SUMMARY1. Intake and digestibility were determined in a trial with 30 British Friesian calves given diets containing straw and either 3·2 (H), 2·9 (M) or 2·6 (L) Meal metabolizable energy per kg dry matter. For one series of diets the straw was chopped and the diets were made into cobs (1·0 × 2·5 × 4·0 cm); for a second series the straw was milled and the diets were made into pellets (1·0 × 1·25 cm)2. Calves given the H diets containing either chopped or ground straw ate and gained less well than calves given M and L diets but there were no differences in feed intake or growth between calves given M and L diets.3. The retention of feed residues was greater and the flow of fluid out of the rumen was less for cattle offered the H diet than the L diet.
Effect of early weaning on the performance of male buffalo and cattle calves
Authors: El-Naggar A. A. , El-Shazly K. , Ahmed I. A. 
Published: September 2010

SUMMARYForty-eight uncastrated buffalo male calves and 16 male Friesian × Egyptian Native calves were used in two experiments to study the effect of weaning age on the performance of calves fed on a high concentrate ration after the first four months of age. Half of the buffalo calves were weaned at 120 days of age on to 330 kg whole buffalo milk (late-weaned) and the other half were weaned at 45 days of age on to 100 kg whole buffalo milk (early-weaned). Cattle calves were weaned at 31 days of age on to 65 kg whole cow milk. At the age of 7 days the calves were put on a high energy ration of 74% total digestible nutrients and 13·5% digestible protein. After 125 days of age all calves were offered a high concentrate ration (cottonseed cake and rice bran in the ratio of 1:1, plus 2% Ca(OH)2 and 1% common salt). Air-dried roughage was supplied at a level of ½% of the body weight. Buffalo and f-Native calves reached a slaughter weight of 400 kg or more about 540 days of age. Three-quarters Friesian calves reached the same weight at 480 days of age. The high concentrate ration caused a high incidence of bloat in ¾Friesian bulls. The efficiency of feed utilization was better for cow calves than that for buffalo calves. The system of early weaning of buffalo calves proved to be most economical and saved about 26% of the cost per kg live-weight gain. Slaughter experiments indicated that fat deposition was greater in male cattle of 400 kg than in buffalo bulls.
Influence of energy and protein concentration in the diet on the performance of growing pigs 3. Response to differences in levels of both energy and protein
Authors: Cooke R. , Lodge G. A. , Lewis D. 
Published: September 2010

SUMMARYOne hundred and twenty eight gilts by Landrace sires out of Large White × Landrace females were allocated on the basis of litter relation-ship and initial weight to 16 treatments involving the individual feeding of four dietary protein levels (approximately 15%, 18%, 21% and 24% CP) at each of four energy levels (2830, 3100, 3375 and 3585 kcal DE/kg air-dry feed). Amino acid balance (as% of total CP) was maintained relatively constant, using synthetic lysine and methionine where necessary. Growth performance was measured over a live-weight range of 23 kg to 59 kg, at which latter weight the pigs were slaughtered for carcass evaluation by dissection of the middle ‘joint’ from a half carcass. Linear carcass measure-ments were also taken. There was a significant energy × protein interaction only for killing-out percentage; for all other measures the main effects could be assessed independently. Increase in dietary energy value gave linear increase in growth rate (GR) and improve-ment in efficiency of feed conversion (EFC), accompanied by linear decrease in lean percentage and increase in fat percentage. Increase in dietary protein level gave an increase in GR and improvement in EFC with the first increment (from 15% to 18% CP), but depressions in both these characteristics with the final increment (from 21% to 24% CP). Lean percentage increased and fat percentage decreased with the first protein increment, with no further significant changes. Calculation of daily rates of tissue deposition indicated that maximum rate and efficiency of fat-free carcass gain could be attained with the second lowest energy and protein levels tested (i.e. 3106 kcal DE/kg and 18·2% CP).
Genetic and non-genetic factors affecting body weights in Sahiwal × Friesian crosses
Authors: Taneja V. K. , Bhat P. N. 
Published: September 2010

SUMMARYThe data were collected from seven dairy farms in India on Sahiwal × Friesian crosses over a period of 30 years (1937–1966). There were nine distinct genetic groups (grades); Sahiwal, 1/8, 1/4, 3/8, 1/2, 5/8, 3/4 and 7/8 Friesian and Indian Friesians (animals having 15/16 or more Friesian blood).Least-square analysis of variance was run to examine the effects of grades, farms, periods, seasons, and breed of sire on body weights at birth, 19 weeks, 12 months and 3 years. The effects due to grades, farms and periods were significant for all the traits. The effects due to season and breed of sire were significant for all traits except for weight at 3 years.The least-square constants showed that, with increase in Friesian inheritance, birth weight increased considerably, while the increase in body weights at 19 weeks, 12 months and 3 years was only marked up to the 1/2-Friesian group.
A Comparative study of some carcass characteristics of Sudan Desert sheep and goats
Authors: Gaili E. S. E. , Ghanem Y. S. , Mukhtar A. M. S. 
Published: September 2010

SUMMARYMale Sudan desert sheep and goats of three age-groups, young, yearling and mature, were used to compare some of their carcass characteristics when reared under range conditions and in feedlot. Carcass traits studied were the dressing percentage, the percentage of bone in the carcass and wholesale cuts, chemical composition of meat, and muscle fibre thickness. An organoleptic test was carried out on meat from the fattened animals.The dressing percentage, percentage of edible meat, chemical fat and muscle fibre thickness were increased by fattening in the feedlot. Increases were also observed with advancing age, but the effect was more marked in fattened than unfattened animals. Goats yielded a higher carcass weight per unit live weight than sheep, the stomach content and skin weight relative to live weight being greater in the sheep than in the goats. Goats were shown to possess less chemical fat and thicker fibres than sheep. Taste panel scores revealed a highly significant (P < 0·005) treatment effect on tenderness and a significant (P = 0·5) treatment effect on juiciness in relation to age and species. Taste panel flavour scores were not associated with animal age or species.
A note on the need for supplementary nitrogen in diets for fattening beef cattle
Authors: Kay M. , Macdearmid A. 
Published: September 2010

SUMMARYThirty British Friesian steers were given either a pelleted diet of bruised barley and ground barley straw (70:30) containing 9·4% crude protein (N × 6·25) or a similar diet with urea or soya bean meal added to raise the crude protein content to 15·0%. Up to a live weight of 200 kg, the growth rate and feed conversion of steers were improved by supplementary nitrogen and urea provided this as effectively as soya bean meal. Beyond 200 kg there were no differences in growth rate or feed conversion between any of the experimental treatments.
Studies on Belgian Pietrain pigs 2. A comparison of growth and carcass characteristics of Pietrain used in three breed crosses with Landrace, Large White and Hampshire breeds
Authors: Curran M. K. , Lean I. J. , Duckworth J. E. , Holmes W. 
Published: September 2010

SUMMARY1. The growth, feed consumption per unit weight gain, carcass characteristics and some aspects of meat quality were studied in two trials with crosses derived from Landrace (L), Pietrain (P), Hampshire (H) and Large White (LW) breeds.2. In Trial 1, 96 pigs of both pure Landrace and LW(× (L♀ × P♂)♂ origin were studied up to slaughter weights of 64 and 91 kg live weight. In Trial 2, Landrace, LW♀ × (L♀ × P♂)♂ and LW ♂x (P♀x L♂)♂, (H♀ × P♂ × L♂ and (H♀ × P♂)♀ × LW♂ pigs were compared up to 91 kg live weight using 48 pigs of each type.3. All crossbred types showed better economy of production than Landrace when assessed by live-weight gain and feed consumption per unit weight gain. Their carcasses contained greater quantities of lean meat and similar quantities of rind, bone and fat than Landrace at comparable weights, but they exhibited a variable tendency to poorer meat quality. LW × (L × P) and LW × (P × L) carcasses at 91 kg live weight were shorter than Landrace; 4% and 14% of pigs in trials 1 and 2 respectively were less than the currently acceptable length of bacon pigs (775 mm). (H × P) × LW and (H×P)×L carcasses at this weight were much shorter; 34% and 38% respectively were less than 775 mm.
Energy supplementation of silage for ewes in late pregnancy
Authors: Sheehan W. , Lawlor M. J. 
Published: September 2010

SUMMARY1. Four groups of 20 ewes were individually fed in late pregnancy on: (1) silage ad libitum, (2) silage ad libitum and 12 kg rolled barley, (3) silage ad libitum and 23 kg rolled barley, (4) pelleted milled dried grass ad libitum. The concentrate was offered on a rising plane over the last 6 weeks of pregnancy. After parturition the ewes and lambs were put on spring pasture.2. The intake of silage by twin-bearing ewes fell slightly but nonsignificantly during week 16 of pregnancy but thereafter remained steady up to lambing. There was no other decline in intake on any of the treatments. Barley, however, significantly depressed silage intake when the quantity was increased above 282 g per day.3. Single-bearing ewes, except those on treatment 1, gained in net body weight during late pregnancy. Twin-bearing ewes on treatment 4 gained in net body weight while those on the other treatments lost weight.4. Birth weights of single lambs from ewes on treatment 1 were significantly lower than those from treatment 3. This was the only significant difference in birth weight or subsequent growth rates of single lambs. Birth weights of twin lambs on treatment 1 were significantly lower than those on the other treatments.5. The birth weight of twin lambs appeared to be an important determinant of subsequent performance, and may thus be a valuable criterion of the adequacy of the ewe's diet in late pregnancy.6. With medium-quality autumn silages, 12 kg of barley given during late pregnancy is sufficient to ensure good reproductive performance in ewes.
Fleece characteristics and postnatal fleece development in Finnish Landrace × Merino sheep
Authors: Ryder M. L. , Wilson D. T. 
Published: September 2010

SUMMARY1. Fleece characteristics in Finnish Landrace × Merino and Merino × Finnish Landrace sheep were compared with those of the parental breeds, and although most characters in the crossbreds showed no significant departure from the parental mean, they had similarities to the Merino which imparted commercial value.2. The wool was mostly of 60s quality compared with 58s in the Finnish Landrace, and 64s and over in the Merino parents. Crimp number showed heterosis, being 5 to 6 per cm in the crossbreds compared with 2 in the Finnish sheep and 7 in the Merino.3. The mean fleece weight was 3-5 kg, compared with 2-2 kg in the Finnish sheep and 4-2 kg in the Merino.4. The mean staple length was 13 cm compared with a very variable length around a mean of 16 cm in the Finnish Landrace, and 10 cm in the Merino.5. The fibre diameter was nearer to that of the Merino, but not significantly so (primary mean 29·2 μ, secondary mean 26·6 μ).6. The greater fleece weight of the crossbreds would be expected to be associated with a greater skin follicle density, but they had a secondary/primary follicle ratio of about 10 (compared with 5 in the Finnish Landrace and 20 in the Merino), which did not differ significantly from the parental mean.7. There was some evidence that fibre development was initially more rapid in the crossbred lambs.
The effects of continuous sire selection on the structure and age composition of dairy cattle populations
Authors: Hinks C. J. M. 
Published: September 2010

SUMMARYA numerical model of male and female replacement processes is developed and used to construct a matrix which specifies the numbers of lactations of different parities expressed in a given time period by daughters of bulls used in artificial insemination (AI).Populations resulting from newly established AI breeding programmes contain an unduly high proportion of offspring by young bulls. Subsequently an equilibrium is reached in which offspring of young and tested bulls are present in proportions determined by the relative usage of the two types of sire and by differences in replacement rates amongst their progeny. Once an equilibrium has been reached the numbers of progeny sired by bulls lacking a progeny test proof is extremely small.The use of the technique to solve a number of specific planning problems is demonstrated.
Responses to variations in dietary energy intakes by growing pigs 1. Estimates of digestible and metabolizable energy requirements for maintenance
Authors: Davies J. L. , Lucas I. A. M. 
Published: September 2010

SUMMARYGroups of individually-fed pigs, each of three gilts and three castrates of mean live weights 18, 31, 46, 58, 72 and 80 kg, were given for 20 days feed allowances based on the ARC estimates of energy required for maintenance, assuming an efficiency of utilization of digestible energy (DE) of 77% for maintenance. As the actual diet used had a higher DE value than that calculated before the start of the experiment, DE intakes (260·3 W056) were about 4·0% above the ARC values.There was no statistically significant change in live weight over the period of study. This supports the validity of the ARC estimates, if maintenance is defined as a lack of change in body weight.The metabolizable energy (ME) intakes (248·3 W0·56) which maintained weight were also close to other estimates of ME requirements.