bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characters of economic importance in Welsh Mountain sheep
Authors: Dalton D. C. 
Published: September 2010

1. The influence of seasonal, maternal and genetic variation on body weight and fleece characters of Welsh Mountain sheep is reported.2. Fertility and rearing ability of ewes improved from first to third lamb crop.3. Male lambs were on average 0·4 lb. heavier at birth than females. Birth weight increased with number of pregnancies of the dam.4. Early growth of the lamb between birth and marking (24 days old) used partly as a measure of milk production of the ewe, was greater in males than in females. Lambs born to older ewes made the greatest gains over this period, although the trend was not significant.5. Weaning weight of the lamb was affected by the dam's weight at tupping, the number of preceeding pregnancies, her milk yield and also by the season in which the lamb was born. Despite these effects weaning weight proved a good guide to the weight (at subsequent matings) at 1½ and 2½ years old.Heritability by intra-sire parent-offspring regression was 0·51±0·07 (P<0·001) and repeatability was 0·43 (P<0·001).6. Fleece weight was not affected by season or age of ewe. However, the heaviest lambs at weaning tended to have heaviest fleeces the following year.Heritability by intra-sire daughter-dam comparison was 0·58±0·11 (P<0·001) and repeatability was 0·46 (P<0·001).7. Staple length measured on the mid-side of the animal had a repeatability between years of 0·56 (P<0·001) while heritability by daughter-dam regression was 0·38±0·ll (P<0·001).8. Fourteen Welsh Mountain rams were progeny tested. Nine of the rams were purchased at local sales and 5 were home bred. They were not selected for the traits examined.No statistically significant differences were obtained between sire progeny groups for weaning weight and fleece weight.
The effects on production efficiency of oleandomycin and oxytetracycline fed at low levels in the diet of heavy pigs
Authors: Vernon J. , Mercer E. A. , Rosen G. D. 
Published: September 2010

Results are presented of an investigation involving 328 pigs on 7 farms in East Anglia, on the effect of oxytetracycline (10 g./ton), oleandomycin (2·5 g./ton) and oxytetracycline (10 g./ton) plus oleandomycin (2·5 g./ton), on the live-weight gain, feed consumption and feed conversion efficiency of pigs from weaning to slaughter at approximately 260 lb. live-weight. Effects on number of days from weaning to slaughter and carcass characteristics are also given.Both antibiotics gave significant improvements in daily live-weight gain (5·4% for OTC and 4·0% for OM) and feed conversion efficiency (3·9% for OTC and 2·3% for OM). There was a significant negative interaction between the antibiotics on live-weight gain from weaning to slaughter.The average number of days from weaning to slaughter was significantly reduced by both antibiotics (5·8 days for OTC and 5·4 days for OM) and there was a significant interaction between antibiotics.Feed conversion efficiency for all pigs was significantly better on those farms where antibiotics had not previously been used but the antibiotic treatment effects were the same in both categories of farm studied.
Genetic parameters of British Large White bacon pigs
Authors: Smith C. , King J. W. B. , Gilbert N. 
Published: September 2010

Estimates of heritabilities and genetic correlations among 35 measurements and scores of British Large White bacon pigs are reported. The data came from pigs tested at the five National Progeny Testing Stations during the period autumn 1957 to spring 1959, and comprised full records on 1936 pigs from 200 sires. Independent analyses were carried out for each sex, and adjustments were made to the data for differences among stations, six-monthly periods and weight at slaughter.Genetic parameters were estimated from sire components of variation and covariation obtained by conventional heirarchical analyses of variance and covariance. Estimates of the heritabilities and their standard errors are given in Table 2, and of genetic and phenotypic correlations in Table 3. These estimates, which agree in general with other estimates in the literature,, indicate that a large part of the variation and covariation is of genetic origin and that carcass traits, growth rate and food conversion efficiency are amenable to change by selection. Moreover, no serious antagonisms were found to exist with regard to improvement by selection.An attempt has been made to summarise the correlation matrix pattern among 24 of the more important traits by using a principal component analysis. The first two principal components account for a disproportionate fraction of the correlation pattern especially of the genetic correlation matrix. Two principal components are given for each trait; the first may be associated with measurements of fat depth.
Fleece characteristics of three strains of Scottish Blackface sheep
Authors: Doney J. M. , Smith W. F. 
Published: September 2010

Fleece characteristics of three distinct strains of Scottish Blackface sheep were studied by sampling eighteen ewes of the Lanark, Galloway and Lewis strains on three occasions in a single year. During the period of maximum growth the Lewis strain, which is largely of historical interest, differed significantly from the others in S/P ratio and mean weight, diameter and degree of medullation in fine and coarse fibres. The differences between the other two strains were small and although a considerable range in fleece characteristics was found, most of the whole fleeces would be classed as ‘medium’ wool.All three strains showed a considerable reduction in follicle output during the winter and spring months when differences amongst them were minimised.
The effect of the proportion of roughage in the diet, diethylstilboestrol implantation and space allowance on the performance of Israeli-Friesian intact male calves
Authors: Holzer Z. , Ilan D. , Levy D. 
Published: September 2010

SUMMARYThe effects of the proportion of hay in the diet (18 or 40%), implantation of diethylstilboestrol and the type of housing on the performance of male calves was examined over the growth period from 250 to 500 kg live weight in a 2×2×2 factorial experiment. The dry-matter consumption per 100 kg of live weight was lower and the live-weight gain and efficiency of conversion of crude metabolizable energy was higher with the diet containing 18% of hay than with that containing 40%. Diethylstilboestrol implantation had only a small effect on performance. Animals that were allowed yard space in addition to pens gained less rapidly, were less efficient in the conversion of energy into live weight, and were somewhat leaner, than those restricted to pens.
Performance and carcass composition of docked and control fat-tailed Kellakui lambs
Authors: O'Donovan P. B. , Ghadaki M. B. , Behesti R. D. , Saleh B. A. , Rollinson D. H. L. 
Published: September 2010

SUMMARYNinety-three Kellakui fat-tailed single lambs were assigned after birth to a 2×2×2 factorial experiment; 46 were uncastrated males and 47 were females. About half the lambs of each sex were docked before they were 1 week old. Half the lambs had unrestricted milk from the ewes until 115 days of age (phase 1) and the other half received all the ewes' milk for the first 30 days and then about one-third of the milk until weaning at 60 days. Creep feed was avail-able to all lambs from about 3 weeks of age, in addition to 200 g of alfalfa dry matter per lamb daily. From 115 days of age, all lambs were fed on a standard fattening ration until slaughtered at weights of 46 to 49 kg for males and 35 to 38 kg for females (phase 2).Lambs given unrestricted milk were 7·4 kg heavier than restricted lambs at the end of phase 1. Significantly better gains due to docking were observed only for females during phase 2. There was little indication that docking affected feed conversion efficiency. In docked lambs the fat normally deposited in the tail was partially (less than 50%) relocated as subcutaneous plus intermuscular and internal fat. Lean meat percentages of carcasses were similar for docked and control treatments. There is a need to standardize reporting of results from docking experiments to make valid comparisons.
Effect of diets containing different levels of wheat straw on lamb performance, feed intake and digestibility
Authors: O'Donovan P. B. , Ghadaki M. B. 
Published: September 2010

SUMMARYA total of 120, 6–7-month-old fat-tailed uncastrated Kellakui lambs were randomly allotted to three groups, given fattening diets for 93 days and then slaughtered. The diets contained 10 (A), 20 (B) or 30% (C) coarsely chopped wheat straw; the latter was increased at the expense of dried beet pulp. All diets contained 45% ground barley, 10% beet molasses and 1% ground oyster shells; there were minor adjustments in the cottonseed meal percentage to maintain a similar protein level in all diets.The three diets were also given in sequence to six adult male Kizil (fat-tailed) sheep in a digestibility trial. Further digestion trials were made with chopped wheat straw given alone or supplemented with 400, 800 and 1200 g of a concentrate consisting of 75% dried beet pulp and 25% cottonseed meal; an all-concentrate treatment was also included.Daily gain (g), feed efficiency (kg feed/kg gain) and dressing percentages for lambs given diets A, B and C were, respectively: 154, 9·78, 54·5; 159, 9·85, 53·5; 127, 11·30, 53·1. A significant decrease in daily gain occurred with the highest straw level and considerably more feed was required per unit of gain. Supplementing straw with 400 g of concentrate increased daily dry-matter intake per sheep from 645 g to 1214 g, with further but smaller increases at higher levels of supplementation. Almost linear increases were observed in dry-matter digestibility as more concentrate was given.
Growth rate, feed conversion ratio and carcass traits of Charolais × Holstein-Friesian and Hereford × Holstein-Friesian steers slaughtered at three different weights
Authors: Fahmy M. H. , Lalande Gaspard 
Published: September 2010

SUMMARYThirty one-year-old Charolais × Holstein-Friesian (CH) and Hereford × Holstein-Friesian (HH) steers averaging about 268 kg live weight were used to study the effect of increasing slaughterweight from the traditional 454 kg (1000 lb) to 544 and 635 kg (1200 and 1400 lb) live weight. The steers were fed a growing ration of grain, silage and hay until they weighed 68 kg (150 lb) below the assigned slaughter weight, followed by a finishing ration of grain mixture and maize silage given ad libitum. Average daily gain on the growing ration was 0·91 kg in CH, 14% higher than that in HH steers, while on the finishing ration HH steers, finished at 544 and 635 kg, made higher gains. CH steers were 7·9% more efficient than HH steers in feed conversion. Feed conversion efficiency (total dig. nutrients (kg) per kg live-weight gain) decreased by 10% and 19% respectively as slaughter weight increased to 544 and 635 kg. Live measurements showed that CH steers were generally longer, taller and wider at the hip, whereas HH steers had a greater depth of chest and width of shoulder. CH steers, slaughtered at different weights, had a higher percentage of round and shank, while HH steers had a higher percentage of all other wholesale cuts. Carcass measurements were generally higher in CH than in HH steers. CH steers had a higher percentage of muscle and bone, and lower fat, in the 12th rib. They also had larger areas of m. longissimus thoracis. Fat deposition over and in that muscle was much higher in HH than in CH steers. Under the conditions of this study, 544 kg was found to be the optimum slaughter weight for both groups. Slaughtering steers at 635 kg was found to be economically disadvantageous.
The effects of quantity and distribution of milk substitute on the performance and carcass measurements of artificially reared lambs
Authors: Penning P. D. , Treacher T. T. 
Published: September 2010

SUMMARYTwenty-seven groups of Finnish Landrace × Dorset Horn lambs each of 2 castrated males and 2 females were offered daily quantities of 180, 248 or 343 g of milk substitute dry matter (DM) for 21, 29 or 40 days. Concentrate pellets were available ad libitum and from 22 days of age 150 g of hay per week was offered. When the mean live weight of a group reached 35 kg two castrates and one female from each group were slaughtered and the carcasses appraised.The growth rate and daily concentrate intake of lambs from 48 days of age until slaughter (reported -in this paper) were not affected by previous treatment, but lambs weaned at 40 days had a higher food conversion efficiency in this period (0·266 kg gain/kg feed DM) than those weaned at 21 days (0·244) or 29 days (0·232).Delaying weaning from 21 to 29 and 40 days reduced overall concentrate DM intake from birth to slaughter (from 88·15 to 81·09 and 73·39 kg) but increased growth rate (261, 276 and 288 g/day) and the conversion of total DM consumed to live weight (0·300, 0·311 and 0·350 kg/kg). Increasing the daily allowance of milk substitute from 180 to 248 and 343 g/day also reduced total concentrate intake (84·18, 80·74 and 77·71 kg). Growth rate and food conversion efficiency tended to increase and concentrate DM intake to decrease when the same total quantity of milk substitute was given over a longer period. Castrated males grew faster than females (290 v. 260 g/day).Weaning age generally had a greater effect than daily allowance of milk substitute on carcass measurements. Fat in the carcass tended to increase with increasing weaning age and significant interactions between daily allowance of milk substitute and weaning age were found for some carcass measurements.
Meat production from pigs which have farrowed. 2. Carcass characteristics
Authors: Brooks P. H. , Cole D. J. A. , Jennings W. J. N. 
Published: September 2010

SUMMARYThe carcass characteristics of young adult female pigs (gilts) slaughtered after weaning their first litters have been investigated using three groups of 19 Landrace × (Landrace×Large White) gilts. In two treatment groups gilts were mated at their pubertal oestrus and suckled their piglets for 5 to 11 and 35 to 42 days respectively. These gilts were slaughtered on average 10 days after weaning. A third control group consisted of unmated gilts slaughtered at 118 kg live weight.There was no significant difference in the killing-out percentage for the three groups. The carcasses of the gilts which farrowed contained significantly less fat (P<0·001) than those of the unmated controls. The carcasses of the farrowed gilts had significantly lighter middle sections (P<0·001) and significantly heavier shoulders (P<0·001) than the controls.Despite the variations in tissue yield and distribution, the yield of prime joints for the gilts which had farrowed was only 0·62 percentage units less than that of the controls.No commercially significant variations between groups in meat quality were observed.
Some consequences of high flock prolificacy in an intensive grassland sheep production system
Authors: Boaz T. G. , Tempest W. M. 
Published: September 2010

SummaryAn intensive sheep production system using flocks of 100 Scottish Halfbred (SHB), 100 Welsh Speckleface (WSF) and 100 Finn Blackface (FBF) ewes maintained by 8, 4 and 6 ha grassland respectively for a 5-year period, was investigated to establish the consequences of high flock prolificacy and the measures taken to achieve it, including PMS administration. Mating occurred in late October/November at ewe: ram ratios of 25 or 33: 1. Ewes were housed in winter and fed silage, with supplementary cereals in late pregnancy. Lambs in excess of 2 (SHB) and 1 (WSF and FBF) per ewe were artificially reared and fattened indoors; ewes and lambs at grass were rotationally grazed (with forward creep grazing by the lambs). Prolificacy in the SHB breed was 225 lambs born per 100 ewes mated for untreated ewes and 237 for hormone-treated ewes; 119 and 155 respectively for WSF ewes; and 255 for FBF ewes (all untreated). Lambs sold per 100 ewes mated were: for SHB, 200 and 177; WSF, 102 and 107; FBF, 201.Good ewe condition and heavy live weights at mating were associated with appetite problems on silage in late pregnancy; PMS injection with a failure to secure conception rates above 80% at the critical oestrus and a markedly lower prolificacy for ewes conceiving at later oestruses; mating in the middle of the breeding season and March/April lambing with slow lamb growth rates on grass in July and August. Hormone-induced high prolificacy was associated with a greater proportion of large multiple litters than natural high prolificacy, and consequent smaller lamb birth weights and more perinatal mortality. There was a significant negative regression relating fleece weight with litter size. The results suggest the existence of an optimal level of prolificacy for the system employed.
The effect of an anabolic steroid on the performance and carcass measurements of gilts and barrows in the finishing stages of growth
Authors: Williams I. H. , Dunkin A. C. 
Published: September 2010

Summary1. An experiment involving 64 individually-penned pigs (32 females (gilts) and 32 castrated males (barrows)) was conducted over the live weight range 50 to 83 kg, to study the effects of a parenterally administered anabolic steroid upon the performance and carcass measurements of gilts and barrows given either a 15·0% or an 18·8% crude protein (CP) diet at two different levels.2. The steroid significantly improved both daily weight gain (+5·2%) and food conversion ratio (+4·8%) of gilts and barrows.3. There were no significant treatment interactions for either daily weight gain or food conversion ratio, but the data suggest that gilts responded to the hormone to a greater extent than barrows at the particular dose level of the steroid administered.4. The steroid significantly improved the carcass, as assessed by linear backfat measurements, of pigs given the higher CP diet but had no effect upon carcass measurements of pigs given the lower CP diet.
Relationship between live weight, age and dry-matter intake for beef cattle after different levels of food restriction
Authors: Lopez Saubidet C. , Verde L. S. 
Published: September 2010

SummaryFive groups of 24 Aberdeen Angus steers, initially 8 months old and 185 kg in weight were subjected to varying degrees of restriction of energy intake, by feeding them on diets containing 1·45 to 2·85 Meal metabolizable energy (ME)/kg dry matter (DM) for 16 weeks. During the realimentation period that followed, all animals were fed ad libitum on the diet containing 2·85 Meal ME/kg DM. When realimentation began the feed consumption of all animals, which had been markedly different, rapidly became similar. When compared at equal live weight the restricted animals had higher intakes than the controls; at an equal age, however, feed intakes were practically the same. This led us to discard compensatory feed intake as a possible explanation for compensatory growth. Age explained 65% of the variability in feed intake, live weight explained 43% and both parameters jointly explained 73%. It is concluded that in restricted and realimented animals, age is a better predictor of feed intake than live weight. Compensatory growth is attributed to a lower maintenance requirement in restricted animals because of their lower live weight at the beginning of the realimentation period.
A note on short term selection for birth weight in mice
Authors: Eklund J. , Bradford G. E. 
Published: September 2010

SummaryA short-term selection experiment was undertaken to estimate the realized heritability for birth weight in mice.A cross of two strains was used as a base population, from which heaviest and lightest birth weight individuals were selected to initiate an up (JU) and a down (JD) selected line. Selection was applied on a within-litter basis for six generations. By the end of the experiment, the two lines differed by 0·20 ± 0·01 g. The heritability, estimated from the regression of cumulative response on cumulative selection differentials and adjusted to that of individual values, was 0·14 ± 0·02. Six-week body weight, averaged over both sexes, was higher in line JU than in JD by 1·0 ± 0·3 g at generation 6. Litter size was higher in line JU in every generation, the regression of the divergence between JU and JD on generation number being 0·13 ± 0·03.
Maternal effects and selection response with an application to sheep data
Authors: Hanrahan J. P. 
Published: September 2010

SUMMARYThe implications of genetic variation in maternal performance for the relative merits of common selection strategies have been investigated. If the accuracy of progeny testing is computed without taking maternal effects into account, the estimate is biased upward. This bias increases as the correlation between direct and maternal genetic effects decreases from positive to negative values. The relative efficiency of progeny and performance test selection is a function of the heritability of direct and maternal genetic effects and the correlation between them. In terms of genetic gain per unit time, progeny testing is almost always less efficient than performance testing. For sire line improvement progeny testing is relatively more useful but is still likely to be less efficient than performance test selection unless there is a negative correlation between direct and maternal genetic effects or the correlation between purebred and crossbred direct genetic effects is very low or negative.Analysis of body weight at 6 and 14 weeks of age in Galway sheep has shown that maternal genetic effects are an important source of variation in this population.
The cellularity of backfat in growing pigs and its relationship with carcass composition
Authors: Wood J. D. , Enser M. B. , Restall D. J. 
Published: September 2010

ABSTRACT1. Using 12 castrated Large White pigs, the way in which the size and number of recognizable fat cells (i.e. > 6·0 μm) increases during growth from 26 to 109 kg live weight, and the relationships between fat cellularity and body fat content were determined.2. Fat biopsy samples were taken at 87, 145 and 188 days of age from the shoulder region. This region grew rapidly in volume but was early maturing since its relative growth during the period of the experiment was low compared with other regions, particularly the mid-back to loin region.3. The growth of fat that occurred during the experiment was due to increases in both the size and number of recognizable cells. There was no indication that the number of cells had become constant even at 188 days of age.4. Subcutaneous or total fat expressed as a percentage of total dissectible tissue weight was related quite closely (r= 0·6 to 0·7, residual s.d. about 8% of mean fat percentage) to average fat cell size measured at 145 and 188 days. The number of cells at these times, defined as the number in a cylinder whose depth was known and whose cross-sectional area was 1 mm2on day 1, was not significantly correlated with whole body fatness.5. Appetite was strongly linked to the rate of fat deposition and to the weight of fat at 188 days, but not to fat expressed in percentage terms. This was, however, closely related to the corrected food conversion ratio (r= 0·90, residual s.d. 2% of mean total fat percentage).6. Fat thickness measured by ultrasonics before slaughter was no better as a predictor of percentage fat than average fat cell size.