bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of production records from a lowland sheep flock 2. Flock statistics and reproductive performance
Authors: Forrest P. A. , Bichard Maurice 
Published: September 2010

SUMMARYThe reproductive performance of a lowland flock of Clun Forest ewes is reported. During the period from 1955 to 1966, over 1300 ewes entered the flock and more than 4800 lambing records were obtained. The effects of culling and death on the records available were investigated and it was found that the reduction of the material caused by death was random, while that caused by culling was related to previous performance.Barrenness decreased with age, and for ewes aged 1, 2 and more than 2 years was 44, 7 and 5%. Average litter sizes (ALS) over the same ages were 1·15, 1·55 and 1·75. Accordingly the number of lambs born per ewe mated and present at lambing also increased with age of ewe, and values for the same ages were 0·64, 1·44 and 1·68.An analysis of over 170 ram mating groups, consisting of ewes older than 1 year, revealed no differences between rams on the ALS of their mates. The results of a similar smaller analysis of barrenness among 1-year-old ewes also showed no evidence of a ram effect.
The effects of partial neutralization with sodium bicarbonate or ammonia and the feeding of blood meal on the voluntary intake of a whole-crop barley silage by sheep
Authors: Wllkins R. J. 
Published: September 2010

SUMMARYSilage made from a whole crop of barley was offered to sheep without neutralization or after partial neutralization to pH 5·4 to 5·5 with sodium bicarbonate or ammonia. In a further treatment the un-neutralized silage was supplemented with blood meal administered each day as a drench. Total organic-matter intake and nitrogen retention were significantly higher for the sheep receiving the blood meal supplement than for any of the other treatments, which did not differ significantly one from another. It is suggested that the intake of the un-supplemented silage was limited by a low uptake of amino acids from the intestine.
Differences between groups of lamb carcasses chosen for good and poor conformation
Authors: Jackson T. H. , Mansour Y. A. 
Published: September 2010

SUMMARYNinety-six lamb carcasses drawn from six batches of lambs commercially consigned to an abattoir were analysed for characteristics which may affect their economic value. From each batch carcasses were selected in equal numbers into two classes of ‘good’ or ‘poor’ conformation according to traditional standards. Carcasses selected for ‘good’ conformation were heavier (P<0·05) and fatter (P<0·05), slightly shorter in carcass length and hind leg length (P<0·05), greater in circumference (P<0·001) and width (P<0·001) of the hind leg, slightly greater in muscle weight (P<0·05) but no greater in bone weight than those of poor conformation. The yield of prime retail joints was similar in the two conformation classes but the ‘good’ conformation class had a higher proportion of loin and rib joints and lower proportion of hind leg joint (P < 0·01) although these differences were not considered to be of commercial importance. There was a lower proportion of the carcass fatty tissue in the hind leg joint of the ‘good’ conformation class (P < 0·05). Muscle-to-bone ratio and area of ‘eye muscle’ (M. longissimus thoracis) appeared to be little affected by selecting for conformation differences. Depth of fleshing as indicated by the weight of muscle in the hind leg per 10 cm length, was 40 g (6%) heavier in the carcasses of the ‘good’ conformation class. This contrasted with the much greater differences, between batches, of 290 g (40 to 50%). Between batches there were significant differences for all the measures taken except the yield of preferred retail cuts. In the main the batch differences were greater and commercially more important than the conformation class differences.
Prediction of the Energy Requirements for Growth in Beef Cattle 1. The irrelevance of fasting metabolism
Authors: Webster A. J. F. , Brockway J. M. , Smith J. S. 
Published: September 2010

SUMMARY1. According to the Agricultural Research Council (1965) energy retention in cattle is predicted from metabolizable energy (ME) intake, the net availabilities of ME for maintenance (km) and for fattening (kf) and measurements made of fasting metabolism (F). The present experiments were designed to examine the validity of the use of F as a basis from which to predict energy retention.2. Four British Friesian and four Aberdeen Angus steers were fed, from weaning to slaughter at about 450 kg, a barley-based, pelleted diet at two levels calculated to yield overall efficiencies of retention of ME of 20% and 10% respectively. Successive measurements were made of the energy balance of each animal at intervals of 4 to 8 weeks.3. The metabolizability of the diet was measured for both sheep and cattle. In both species metabolizability was greater at the higher level of feeding. In sheep kf measured directly or estimated from metabolizability was 0·61.4. Measured values for F in cattle agreed closely with values given by the Agricultural Research Council.5. Basal metabolism in the growing animal (F') was predicted by extrapolation to zero intake of measurements made on animals in positive energy balance. Log F' during growth was proportional to log body weight0·73. Expressed in terms of the usual exponent of metabolic body size, F' was about 440 kJ/kg0·75 per 24 hr throughout growth. There were no major differences in F' attributable to breed or to level of food intake.6. The results indicate that F is not a good basis from which to predict energy retention in steers.
Variations in immunoglobulin concentrations in Merino and Scottish Blackface lambs
Authors: Halliday R. 
Published: September 2010

SUMMARYThe concentrations of maternal immunoglobulin in 2-day-old lambs varied widely. They were significantly correlated with the lengths of pregnancy and the serum protein concentrations of the adult female sheep (ewes), but not with the colostrum immunoglobulin concentrations, nor with the weights or ratios of weights of the lambs and ewes. The mean concentrations were as high in Merino as in Blackface lambs.Although there was some evidence that colostrum production was higher in ewes with twins than in ewes with single lambs, the immunoglobulin concentrations in the lambs fell significantly as litter size increased. They were significantly higher in male than in female twins, and in twins from litters containing both sexes than in twins from litters of one sex, but the difference between single males and females was not significant. Nor was the difference between the first and second born of each pair of twins. Twins and triplets born to ewes aged 7 years or more had particularly low concentrations. No other effects of the age of the ewe were found. The concentrations fell significantly as the date of lambing during the season advanced, and there were significant annual variations which could not be attributed to the weather. The correlation coefficients for the concentrations in lambs born to the same ewe in successive years were 0·309 and 0·298 (P < 0·001), respectively, for Merino and Blackface lambs.The mean concentration in lambs which died subsequently from infections was significantly lower than in the surviving lambs, but many lambs with very low concentrations survived.
The replacement of skim milk by cooked potato flour in milk diets for calves
Authors: Hinks C. E. , Peers D. G. , Armishaw Alison M. 
Published: September 2010

SUMMARY1. A total of sixty, 7-day-old British Friesian male calves, reared on a conventional early-weaning system, were used in two experiments in which dried skim milk was partially replaced by levels of 7, 14 and 21 % cooked potato flour (CPF). In the first experiment the diets were iso-energetic but differed in total nitrogen contents, whilst in the second experiment, casein was used to make the diets iso-nitrogenous.2. In both experiments, diets containing CPF depressed growth rate from 4 to 18 days on treatment (11 to 25 days of age) and reduced the firmness of the faeces. These effects were correlated with the concentrations of CPF in the diets, live-weight gain being depressed by 20%, and the firmness of the faeces by 14%, for each 10 % inclusion of CPF. After 18 days on treatment (25 days of age) these effects became less pronounced.3. The overall performance of calves to weaning (after 35 days on treatment) was similar on all diets. Daily live-weight gains from 4 to 56 days and 35 to 56 days did not differ between treatments. 4. It was concluded that whilst the inclusion of CPF in the diets of milk-fed calves was unlikely to have any permanent effect on the live weight of calves at 5 or 8 weeks of age its use in milk diets for calves of less than 3 weeks of age must be limited if loose faeces are to be avoided.
A comparison of tissue development in Pietrain and Large White pigs from birth to 64 kg live weight 1. Growth changes in carcass composition
Authors: Davies A. S. 
Published: September 2010

SUMMARYFemale pigs of the Pietrain and Large White breeds, 18 from each, selected to form a logarithmic weight range, were dissected into their major carcass tissues. Relative to carcass growth, fat was the fastest developing tissue in both breeds; fat and muscle grew at a rate higher, and bone at a rate lower, than the carcass. The growth of bone relative to carcass growth was faster in the Large White; differences between breeds in the growth of muscle and fat were not significant. Muscle weights and muscle: bone ratios, estimated at the same empty body weight, were greater for the Pietrain over the entire body weight range studied. There was no significant difference in muscle: bone ratio between the Large Whites used in the present study and those dissected by McMeekan over 30 years previously. The breed difference in the proportion of muscle and bone at the same body weight is attributed to a greater maturity of the Pietrain.
A comparison of tissue development in Pietrain and Large White pigs from birth to 64 kg live weight 2. Growth changes in muscle distribution
Authors: Davies A. S. 
Published: September 2010

SUMMARYHalf carcasses of 18 Pietrain and 18 Large White female pigs were each dissected into 93 muscle units. An allometric analysis of the weight of these units relative to total muscle revealed increasing craniocaudal and distoproximal growth gradients, which were more pronounced in the Pietrain.The greater total weight of muscle, shown previously for the Pietrain at any given body weight over the range studied, was not due to higher muscle weights in any particular region at birth, but at 60 kg body weight was due to heavier high impetus muscles. Heart weight relative to total muscle weight was higher for the Large White over the entire range.It is concluded that for the animals studied the changes in muscle distribution are related to the functional demands of an increase in body size, and that the muscle distribution of pigs can differ between breeds.
A note on the growth of early-weaned Hampshire piglets
Authors: Whittemore C. T. , Illius A. W. 
Published: September 2010

SUMMARYThe appetite and growth of individually-fed, weaned Hampshire and Saddleback piglets and of Hampshire and Large White × Landrace piglets were compared in three experiments from 14 to 49, 28 to 55 and 21 to 45 days of age. There was a reduced rate of growth in the Hampshire piglets, which was not found to be related to any need of Hampshire piglets for a higher quality diet. Neither was there any reduction in the efficiency with which Hampshire piglets used ingested nutrients, nor a differential rate of deposition of any body component. Hampshire piglets ate less food than Saddleback or Large White × Landrace piglets and this reduced appetite was largely accounted for by the lower body size.
A note on the estimation of total lactation yield from production on a single day
Authors: Wood P. D. P. 
Published: September 2010

SUMMARYThe recording of total lactation yield for individual cows can be timeconsuming and costly. Periodic sampling at intervals throughout lactation offers an acceptable alternative, and a single day's production can be made to furnish a useful guide, by using an equation relating total to daily production.Errors of estimation are affected by the degree of consistency of daily production, parity and individual herd management, so that estimates could be biased and have a standard error of nearly 20% if these effects are disregarded. Coefficients in the prediction equation must therefore be developed for individual herds.
Pre-puberal plasma luteinizing hormone concentrations and progesterone concentrations during the oestrous cycle and early pregnancy in Galway and Fingalway female lambs
Authors: Quirke J. F. , Gosling J. P. 
Published: September 2010

ABSTRACTTwenty-four young female sheep, 12 Galways and 12 Fingalways, were used to study the effects of breed and level of nutrition on pre-puberal plasma luteinizing hormone and progesterone concentrations throughout the oestrous cycle and during the first 35 days of pregnancy. The sheep were spring-born and were housed at the end of July when they weighed approx. 34 kg. Equal numbers of animals from each breed were fed on a concentrate diet either ad libitum or at a restricted level that was slightly above their estimated maintenance requirements. The Fingalways reached puberty 1 month earlier than the Galways (11 October ±4 days v. 10 November ±5 days). The restricted animals tended (P < 0·10) to reach puberty later than those fed ad libitum (1 November ±5 days v. 20 October ±4 days). Breed differences in the mean level of plasma progesterone on any day of the oestrous cycle were not significant. The mean daily plasma progesterone concentration was similar for the animals on the two planes of nutrition throughout the cycle, with the exception of day 11 when those fed ad libitum had a significantly higher level (P < 0·01). Plasma progesterone levels in the pregnant females between 5 and 35 days post mating were generally higher in Fingalways than in Galways and were not influenced by plane of nutrition. Plasma luteinizing hormone levels tended to be higher, during the 7 weeks before puberty, in Fingalways than in Galways and in animals fed ad libitum than in those on the restricted level of feeding.
A note on the comparative growth performance of pigs sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars
Authors: Lishman W. B. , Smith W. C. 
Published: September 2010

ABSTRACTThe performance of progeny sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars was compared over the live-weight range 28 to 65 kg. Feeding was twice daily to ‘appetite’ up to a maximum of 2·27 kg meal/day. Breed of boar did not influence rate or efficiency of live-weight gain, mid-line or internal fat depths nor muscle quality. Progeny of Pietrain × Hampshire and Hampshire × Large White sires, compared with those of Large White boars, had higher killing-out percentages (1·4 and 1·2 units) and larger eye muscles in cross-section (19·3 and 11·6%). Significant but small breed differences were noted in joint proportions of the carcass.
A note on the ovulation rate of sheep following treatment with clomiphene citrate
Authors: Land R. B. , Scaramuzzi R. J. 
Published: September 2010

ABSTRACTThe use of the ‘anti oestrogen’ clomiphene to increase the ovulation rate of the sheep was investigated. Although in most trials clomiphene had a positive effect, this effect was small and inconsistent—especially n i relation to dose. It was concluded that the present approach would not lead to a simple technique to increase ovulation rate and the number of lambs born.
Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs
Authors: Quirke J. F. 
Published: September 2010

ABSTRACTGroups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.
Evidence for phenotypic change at the amylase I locus in cattle—an explanation of the apparent heterozygote excess
Authors: Archibald A. L. , Bradley J. S. , Spooner R. L. 
Published: September 2010

ABSTRACTThe amylase (Ami) phenotypes have been determined in sera collected from 244 heifers before 6 months and after 2 years of age. Fifty of these animals exhibited a change in phenotype from Ami C to an apparent Ami BC with age. Using a modified electrophoretic technique these apparent heterozygotes were reclassified as Ami C(E). Eight hundred and nineteen cows, which had previously been shown to have a highly significant excess of heterozygotes at the Ami locus, were also retyped by this modified technique. The apparent heterozygote excess was not found as it was now possible to differentiate between Ami C(E) and Ami BC.
A note on the use of electronic doors for individual feeding of group-housed lambs
Authors: Cammell S. B. , Spooner M. C. , Thomson D. J. 
Published: September 2010

ABSTRACT1. Two groups of artificially-reared lambs were used to evaluate electronic equipment which allowed group-housed lambs individual access to their own food supply.2. Trial group A comprised six lambs in a cross-over design between individual metabolism cages and group-housing with electronic doors to examine the effects of method of housing upon ad libitum food consumption. There were no significant differences in dry-matter intake although it was observed that food consumption was temporarily reduced during the training periods.3. Trial group B comprised 16 lambs used to test established training techniques and to examine the effects of adaptation to electronic doors upon food consumption and live-weight gain over a period of 50 days. There was a reduced intake of food during days 1 to 7 which resulted in the daily dry-matter intakes and live-weight gains for days 8 to 50 and 15 to 50 being higher (P<0·01) than those for the total period (days 1 to 50). It was concluded that a minimum of 7, and preferably 14, days were required for training lambs and for adaptation to a diet provided through electronic doors.
Amino acid requirements of growing pigs. 1. Effects of reducing protein level in diets containing high levels of lysine
Authors: Taylor A. J. , Cole D. J. A. , Lewis D. 
Published: September 2010

ABSTRACTSixty-four growing pigs, with equal numbers of females and castrated males, were fed diets containing from 10 to 17·6% crude protein but in which lysine was maintained at 0·95%. Over the 25 kg to 55 kg live-weight range studied, growth performance was unaffected by a reduction in crude protein level from 17·6 to 14·5%. Below 14·5% crude protein, daily live-weight gain and feed conversion ratio deteriorated linearly. Percentages of lean meat and fat in the middle joint showed similar trends. Significant sex effects were confined to carcass characteristics which indicated that the females produced leaner carcasses. It was concluded that below 14·5% crude protein a deficiency of the next limiting amino acid to lysine, or possibly non-essential nitrogen, depressed growth performance.
Season of birth and the response to hemicastration in lambs
Authors: Land R. B. , Drury D. J. , Fordyce Marjorie 
Published: September 2010

ABSTRACTTestis diameter and body weight were recorded for 37 Finn-Dorset ram lambs born in winter and 38 born in summer 1977 from 8 to 24 weeks of age. Testis growth in summer-born ram lambs reared during a period of decreasing daylength was more rapid than that of winter-born lambs reared during a period of increasing daylength. Hemicastration at 12 weeks of age (19 of the winter-born and 18 of the summer-born lambs) increased the rate of growth of the remaining testis. Season of birth did not affect the response to hemicastration. It was deduced that the feed-back of gonadal hormones on gonadotrophin release was similar in both seasons.
The effect of level and system of concentrate allocation to January/February calving cows on total lactation performance
Authors: Steen R. W. J. , Gordon F. J. 
Published: September 2010

ABSTRACTA randomized block experiment using 108 British Friesian cows was conducted over a 2-year period to assess the effects of level and pattern of concentrate allocation during early lactation on the performance of cows which calve during January and February. The three concentrate levels were 280 (L1), 405 (L2) and 530 (L3) kg during a 74-day post-calving period, and the two systems of allocation were either a uniform daily allowance (uniform system) or a high input for the first 4 weeks after calving followed by a low input (high/low system). The animals had ad libitum access to medium-quality grass silage during the indoor period and in both years were turned out to pasture on 9 April. At pasture they were grazed rotationally in treatment groups at a stocking rate ranging from 6·4 cows ha-1 in the early-grazing season to 4·9 cows ha-1 in the late-grazing season.Mean milk outputs for the indoor feeding period were: high/low system 1577 (L1), 1705 (L2) and 1764 (L3), uniform system 1583 (L1), 1676 (L2) and 1783 (L3) ±33·8 kg; and for the total lactation were high/low system 4625 (L1), 4906 (L2) and 5148 (L3), uniform system 4830 (L1), 4933 (L2) an d 5301 (L3) ±118·9 kg.There was no significant interaction between level and system of concentrate allocation. Feed intake, milk composition, animal live weight and body-condition data are also presented.
The relationship between heterozygosity and heterosis in reproductive traits in mice
Authors: McGloughlin Patricia 
Published: September 2010

ABSTRACTContinuous reciprocal backcrossing results in individuals which are 67% heterozygous, and which, assuming a linear relationship between heterozygosity and heterosis, would be expected to exhibit 67% of the heterosis found in Fi hybrids. An experiment was undertaken to investigate this relationship in the reproductive traits of mice. By crossing and repeated backcrossing in both directions using two unrelated strains of outbred mice, females were produced which were 25, 50, 75 and 100% heterozygous. The crossbred females and the two purebred strains (922 females in all) were mated to a sire line of a genetically distinct strain to standardize foetal heterosis. The reproductive performance of females with different percentage heterozygosity gave estimates of maternal heterosis. A significant positive linear relationship was found between heterozy-gosity and heterosis in litter size, total weight of litter and individual weight of progeny both at birth and at weaning. The relevance of these results for livestock breeding is discussed.