bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental factors affecting beef cow reproductive performance in Botswana
Authors: Buck N. G. , Light D. , Rutherford A. , Miller M. , Rennie T. W. , Pratchett D. , Capper B. S. , Trail J. C. M.
Published: September 2010

Effects on cow reproductive performance, of cow age, parous state, body weight and body-weight change over the breeding season were examined using 6490 annual records from indigenous cows in Botswana.

Calving percentage rose from 69% at 2·5 yr of age to a maximum of 82% at 6 to 7 yr and declined in cows over 8 yr of age. Heifers and previously non-parous cows had a calving percentage of 85%; 8, 18 and 30% higher respectively than parous cows that had calved at the beginning, middle and end of the previous calving season. Cows weighing less than 300 kg at the beginning of the mating season achieved a 50% calving. This rose steadily to 85% as body weight increased to 430 kg.

Cows that lost weight over the mating period achieved a 67% calving, while gains of 20 kg raised this to 76%. Increased weight gains thereafter had little effect on calving percentage. In all cases, as percentages increased, days to conception decreased in a similar manner.

Under these range conditions in Botswana, animals least likely to achieve high calving percentages were young cows; cows which calved previously at the end or middle of the calving season; cows less than 310 kg in weight; and cows gaining less than 20 kg body weight during the mating season.
Alternative forms of genetic controls
Authors: Smith C.
Published: September 2010

The optimum design of genetic controls is considered with respect to several factors, such as a fixed total expenditure, differing costs for males and females, different plans for retaining parents and choosing replacements, the value of keeping spares and the effects of mortality and infertility among individuals in the control.

The effects of mortality and infertility are important for these will tend to reduce the annual effective size and lower the optimum age for replacement of parents. Keeping individuals to a fixed age, without spares, will usually be preferable in practice to the lifetime retention of parents with spares, since spares will be at the expense of other breeding animals. It is shown that with the same total expenditure, the annual effective size of a control may be substantially increased by the appropriate choices among the various factors studied and methods are given for finding the optimum design.
Herbage intake and performance of grazing ewes and of their lambs when weaned at 6, 8, 10 or 14 weeks of age
Authors: Gibb M. J. , Treacher T. T. , Shanmugalingam V. S.
Published: September 2010

Twin lambs grazing with their dams at herbage allowances of 30 or 60 gdry matter per kg live weight per day (low and high, respectively) were weaned at 6, 8, 10 or 14 weeks of age. After weaning, the lambs were given a herbage allowance of 160 g dry matter per kg live weight per day.

Ewes on the low allowance ate less herbage, produced less milk and lost more weight than those on the high allowance. The lambs on the low allowance were lighter at weaning than those on the high allowance (137 v. 168, 16·2 v. 20·5, 17·9 v. 24·2 and 21·9 v. 30·4 kg at 6, 8, 10 and 14 weeks respectively).

Lambs weaned from ewes on the low allowance grew more slowly than the unweaned lambs when removed at 6 weeks, but not when weaned at 8 and 10 weeks of age. Weaning lambs from ewes on the high allowance reduced their growth rates at all weaning ages, despite the weaned lambs being grazed at an allowance which would not limit their intake of herbage. The intake of herbage per unit live weight by weaned lambs reached its maximum at approximately 8 weeks of age. After weaning, intake was higher for lambs from ewes on the low allowance than for those on the high allowance (38 v. 33 g organic matter per kg live weight per day). Lambs slaughtered at 17 weeks of age were heavier from the high allowance than from the low allowance. However, after 17 weeks of age the remaining lambs from the low allowance grew more rapidly than those from the high allowance, and when slaughtered at 25 weeks of age had similar weights. Treatments had no effect on the weights of the body components or carcass dimensions independent of their effect on empty-body weights at slaughter.
Effect of body condition and pasture type on herbage intake, performance during lactation and subsequent ovulation rate in Scottish Blackface ewes
Authors: Doney J. M. , Gunn R. G. , Peart J. N. , Smith W. F.
Published: September 2010

Scottish Blackface ewes in uniform, good, body condition at mating were differentially fed during pregnancy, such that two groups lost 0·15 to 0·20 (groups A and B) and one group gained 0·05 (group C) of maternal live weight by lambing time. The treatments had little effect on the number of lambs born per ewe lambing (1·39, 1·46 and 148 respectively).

Prior to parturition, group A was transferred to a poor hill pasture, and groups B and C to an improved upland reseeded pasture. Herbage intake by six single- and six twin-suckling ewes from each group was estimated in the 3rd, 6th and 8th week after parturition, and mean daily milk production was estimated on 1 day following each intake measurement period. Herbage intake by six dry ewes in each of groups A and B was also estimated.

There were significant differences amongst groups A, B and C, respectively, in mean organic matter digestibility of the herbage consumed (0·701, 0·771 and 0·773), mean daily digestible organic-matter intake (1·06, 1·46 and 1·46kg), mean live-weight change over the period ( –2·9, +5·4 and +l·3kg) and mean daily milk yield (0·64, 1·93 and 1·95 kg).

By the following mating time, after grazing the same pasture from weaning, there was still a difference in body condition score according to pasture type during lactation (2·08, 2·36 and 2·29, respectively). Ovulation rate measured after mating was consistent with the direct effect of body condition (1·34, 1·56 and 1·52, respectively).
Some behavioural deviations in weaned domestic pigs: persistent inguinal nose thrusting, and tail and ear biting
Authors: Blackshaw Judith K.
Published: September 2010

Groups of pigs were observed from weaning to marketing for the incidence of tail and/or ear biting and persistent inguinal nose thrusting. The 16 groups included single and mixed litters, single or mixed-sex ratios, and comprised up to 12 pigs; 14 of the groups showed biting behaviour and 12 groups showed persistent inguinal nose thrusting behaviour. The onset of biting appeared from 0 to 44 days after weaning, and persistent inguinal nose thrusting was first observed 4 to 22 days after weaning.

There was a significant relationship between the number of pigs biting and being bitten in a group. The high ranks tend to bite middle and low ranks more than expected, the middle ranks bite other middle ranks more than expected, and low ranks bite the least. Within any rank there was no difference between male and females biting or being bitten. The most common situation was to have, in a group, some pigs which only tail bit, others that only ear bit, and others which both tail and ear bit. It is suggested that biting is a learned response spread by visual communication, so that visual barriers around affected groups may help to limit the spread of an outbreak.

In persistent inguinal nose thrusting behaviour, rank was important, as the top ranking pigs were the most most likely to show persistent inguinal nose thrusting. Persistent inguinal nose thrusting may have its origin in udder seeking, exploratory or rooting behaviour, but becomes used mainly by dominant pigs. The behaviour is halted by the pig which received the nose thrusts moving away.
A note on the effect of low levels of biotin in milk substitutes for neonatal pigs
Authors: Newport M. J.
Published: September 2010

Pigs weaned at 2 days of age were given a milk substitute until 28 days of age containing either 10 or 52 fig biotin per kg dry matter. During the last week of the experiment a slight deterioration in the ratio of feed: gain (0·1 > P > 0·05), but not in weight gain, was found in pigs given the low-biotin diet. No signs of biotin deficiency were observed, but pigs given the low-biotin diet had lower concentrations of biotin in the liver and carcass. Most of the biotin was in the liver. These results suggest that 10 fig biotin per kg dry matter may be adequate for pigs until at least 28 days of age.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 2. Chemical and dissectible body composition
Authors: Thompson J. M. , Butterfield R. M. , Perry Diana
Published: September 2010

The changes in chemical and dissectible body composition from birth to maturity were examined in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. Body composition was examined in 34 mature animals and the maturing patterns for body components calculated using mean values from the mature animals and individual data from 106 immature animals.

In the 34 mature animals, strain had no effect on the proportions of chemical and dissected fat, protein and muscle in the body. The weight-plus had greater proportions of ash and carcass bone in the body than the weight-minus animals. Mature rams had lower proportions of chemical and dissected fat and greater proportions of protein, muscle, ash and carcass bone in the body than mature ewes.

The weight-minus animals had later maturing patterns for both chemical and dissected fat than the weight-plus animals. Strain had no effect on the maturing patterns for protein and muscle, although both ash and carcass bone were later maturing in the weight-plus, than in the weight-minus animals. Chemical and dissected fat were later maturing in the ewes than in the rams, whereas protein, muscle, ash and carcass bone were earlier maturing in the ewes than in the rams.

The weight-minus animals were fatter at the heavier body weights, although there was a trend for the weight-plus animals to be slightly fatter at the lighter body weights. When compared at the same stage of maturity of body weight, strain differences in the proportion of fat in the body declined as the animals matured. Compositional differences between the rams and ewes varied according to the body weight or stage of maturity of body weight at which they were compared.
A comparison of carcass traits in Scottish Blackface and Welsh Mountain lambs and their crosses
Authors: Lee G. J.
Published: September 2010

A total of 219 lambs of the Welsh Mountain (W) and Scottish Blackface (B) breeds, and six types of crossbred with varying proportions of the two breeds from a cyclical crossbreeding experiment, were slaughtered in six groups at fortnightly intervals from 6 to 8 months of age. Each group had balanced numbers of each genotype and each sex. Genotype differences and effects of heterosis were estimated. Fat grades were assessed by farm staff before slaughter and Meat and Livestock Commission fat and conformation scores and external linear hindquarter measurements of each carcass were recorded.

At the same age, W carcasses were lighter (W: B = 0·86, W = 11·7 kg, B = 13·4 kg) but were more mature and had more kidney fat (W: B = 1·73) and higher fat and conformation scores especially in the loin region, but relatively shorter, thinner legs. At the same degree of maturity (carcass weight/estimated mature carcass weight), the Welsh carcasses had more kidney fat but the difference in leg measurements was reduced, and the differences for fat and conformation scores disappeared. When compared at the same grade, the Welsh lambs were 2 kg lighter and had higher conformation scores suggesting comparative undergrading, especially by the farm assessors. Results for crossbred lambs were as predicted from their breed composition and there was no evidence of heterosis.

The results suggest that at the same estimated carcass fatness, the Blackface has the potential to produce a heavier carcass but is later maturing, taking approx. 12 days longer to reach this degree of fatness.
Dietary amino acid balance and requirements for pigs weaned at 3 weeks of age
Authors: Zhang Y. , Partridge I. G. , Keal H. D. , Mitchell K. G.
Published: September 2010

Nitrogen balance was measured in a series of experiments to determine the optimum balance between lysine, threonine and methionine plus cystine by successive additions of the free amino acids to a basal diet of barley, soya bean meal and tallow. The basal diet had a calculated digestible energy (DE) value of 14·5 MJ/kg and a crude protein content of 146 g/kg. The ranges of total lysine; threonine and methionine plus cystine tested were (g/kg) 6·6 to 11·8, 4·9 to 6·9 and 4·3 to 71, respectively. Latin-square designs were used involving a total of 33 pigs. Nitrogen utilization was optimized in pigs of 3 to 9 weeks of age when each kg of diet contained 10·5 g lysine, 6·4 g threonine and 5·0 g methionine plus cystine, corresponding to a ratio of 100: 61: 48. Thereafter, five diets were formulated in which the same ratio was maintained, but at different protein levels (129 to 192 g/kg). Again the diets were based on barley, soya bean meal and tallow supplemented with free amino acids. These diets were compared, in both nitrogen balance and performance experiments, with a conventional early-weaning diet with a protein content of 240 g/kg. All six diets had the same calculated DE value (14·5 MJ/kg). The N balance experiment was of Latin-square design and involved 18 pigs, and the performance experiment used 36 pigs fed individually from 3 to 9 weeks of age. A diet containing 0·99 g lysine per MJ DE (14·4 g lysine and 192 g balanced protein per kg) was considered to be adequate on the basis of the growth rate and food conversion efficiency results obtained.
Combining clonal response and genetic response in dairy cattle improvement
Authors: Teepker G. , Smith C.
Published: September 2010

Repeated cloning of bovine embryos by nuclear transfer, producing large clones of monozygous animals, may be possible in the future. Initially, clones could be tested and the best one selected and spread over the commercial population by embryo transfer. Further genetic improvement could be obtained by rebreeding a number of the best clones to produce a new set of clones. However, the testing and selection systems to pick the best clone (for short-term clonal response) and to pick clones with the best breeding values (for long-term genetic response) are different. The objective of this study was to derive a system which achieves both high clonal and high genetic responses. An adult MOET (multiple ovulation and embryo transfer) scheme with 40 breeding males and 40 breeding females per generation (cycle) was used to maintain adequate genetic variation for continued genetic response. For a fixed set of testing facilities and a given family structure initial clonal response is maximized by testing several members per clone. Long-term genetic response is usually greatest when testing one member per clone. Compromises to obtain both high clonal response and high genetic responses were from 95 to 100% efficient.
Effects of low levels of food intake before and/or after mating on gonadotrophin and progesterone profiles in Greyface ewes
Authors: Rhind S. M. , McMillen S. , Wetherill G. Z. , McKelvey W. A. C. , Gunn R. G.
Published: September 2010

Gonadotrophin profiles during the follicular phase of the cycle prior to a synchronized mating and LH and progesterone profiles at days 2, 6 and 10 post mating were investigated in three groups of 16 ewes. of one group were given 0·5 × estimated metabolizable energy requirements for maintenance (MEM) from 14 days before mating until slaughter 11 days after mating (LL). Ewes of a second group were given 1·5 × MEM during the 14 days prior to mating and then 0·5 × MEM thereafter (HL) and the remaining ewes (HH) were given 1·5 × maintenance throughout the experiment. During the day before mating, plasma samples were collected at 10-min intervals for 8 h and assayed for LH and FSH. Samples were collected at 15-min intervals for 8 h on days 2, 6 and 10 after mating. Each ewe was then injected intravenously with 10 μg LH and samples were collected for a further 3 h. All of these samples were assayed for LH and progesterone. Nutritional treatment did not affect mean follicular phase concentrations of FSH or LH or mean LH pulse amplitude but the mean LH pulse frequency (pulses per h) of LL ewes was lower than that of HH + HL ewes (0·37 v. 0·48; P < 0·05). After mating, mean LH concentrations were unaffected by sampling date or nutritional treatment but the mean LH pulse frequency was lower in HL + LL than HH ewes at day 2 (0·25 v. 0·40; P < 0·01) and day 10 (0·28 v. 0·38; P < 0·05). Mean progesterone concentrations (ng/1) were higher in HL + LL than HH ewes at day 10 (6·77 v. 4·80; P < 0·05) but pulse frequency was not significantly affected. Injection of 10 μg LH on days 2, 6 and 10 after mating was followed by a significant increase in progesterone concentrations. The progesterone response was greater (P < 0·05) in LL + HL ewes than in HH ewes. It is concluded that increased rates of embryo mortality often associated with undernutrition are unlikely to be related to lower circulating progesterone levels per se but may be attributable to reductions in mean LH pulse frequency and consequent changes in progesterone profiles.
The influence of season and management system on intake and productivity of confined dairy cows in a Mediterranean climate
Authors: Moran J. B.
Published: September 2010

The influence of season and management system on the productivity of Friesian cows in a Mediterranean climate was assessed. Intakes of food and water and milk yields were measured in 154 cows over 2·5 years while intensively managed in yards giving access to shelter (free stalls) or that were fully exposed to solar radiation (open lots). Food quality was also monitored to permit estimates of the efficiency of utilization of metabolizable energy for milk production over fortnightly periods.

The highest milk yields and energetic efficiencies were recorded during spring. Energy intakes were highest but energetic efficiencies were lowest during winter. Cows consumed the least food during summer and autumn and drank the most water during summer. The only significant effect of management system was for water intake, which was higher in the open lots than in the free stalls. There was evidence of heat stress in summer and cold stress in winter, but there appeared to be little benefit with milk yields through the provision of shelter.
Growth, carcass composition and serum hormone responses to photoperiod and ovariectomy in heifers
Authors: Zinn S. A. , Chapin L. T. , Enright W. J. , Tucker H. A.
Published: September 2010

To determine effects of photoperiod and ovaries and their interactions on live-weight (LW) gain, carcass composition, growth hormone (GH), insulin (INS) and prolactin (PRL), crossbred beef heifers were utilized. Heifers (no. = 70) were blocked by LW and assigned to a pre-treatment slaughter group for estimation of initial carcass composition or to treatments in a 2 × 2 factorial experiment (no. = 14 per treatment). Main effects were: photoperiod (8 h light (L): 16 h dark (D) v. 16L: 8D) and ovaries (intact (INT) v. ovariectomized (OVX)). Heifers were given a maize-based mixed diet (115 g protein and 11·5 MJ metabolizable energy per kg dry matter) ad libitum once per day at 07.30 h. On days 64 and 138, blood samples were taken every 30 min for 10 h from five heifers in each treatment. On day 144 treated heifers were slaughtered. Relative to OVX heifers, INT heifers had greater (P < 0·01) average LW gain (1·03 v. 1·17 kg/day), carcass weight (252 v. 270 kg) and carcass protein accretion rates (68 v. 82 g/day) but carcass fat accretion was not affected (P < 0·l; 381 v. 399 g/day). Compared with 8L: 16D, exposure to 16L: 8D non-significantly increased LW gain more in OVX heifers (16 kg) than in INT heifers (3 kg). Photoperiod did not significantly influence weight or composition of the carcass. There was no significant interaction between photoperiod and ovaries on carcass composition. Across all heifers GH declined (P < 0·05) and INS and PRL increased (P < 0·05) from day 64 to 138. Compared with 8L: 16D, exposure to 16L: 8D increased PRL on day 64 (P < 0·05; 13·4 v. 28·5 u.g/1) and decreased INS averaged across days 64 and 138 (P = 0·l; 0·71 v. 0·55 u/l) but had no effect on GH. GH, INS and PRL did not differ between INT and OVX heifers. It is concluded that ovariectomy of heifers reduces LW gains, carcass weights and accretion of protein, and that exposure to 16L: 8D partially prevents the loss in LW gain.
The effect of group size on the performance of growing pigs
Authors: Petherick J. Carol , Beattie A. W. , Bodero D. A. V.
Published: September 2010

Three replicates of three group sizes (six, 18 and 36) of grower pigs were housed with the same space allocation (0·66 m2per pig), feeding and drinking space per animal. The animals were mixed and kept together for a period of 22 days. They were given foodad libitum, were weighed weekly and a record kept of the group food intake for the 22-day period. Weight at mixing had a significant effect on weight gains during the 1st week. There was a significant interaction between group size and replicates for weight gains; generally weight gains were lowest in the group size of 36 animals during the first 2 weeks, but in the 3rd week there was no difference between the group sizes. Sex had no effect on weight gains. The variation in weights between group members were significantly greater in the group size of 36 than in the group sizes of six and 18 at the start of the trial, but at the end of the trial there was no difference in the variances of weights in the three group sizes. There was no difference between the group sizes in the variances of the weight gains. There was a significant positive correlation (r = +0·36) between weight at mixing and weight gain for the group size of 18. Group size had no effect on food intake, but the food conversion efficiency of the animals in the group size of 36 was significantly poorer than in the group sizes of six and 18.
Factors influencing the welfare and carcass and meat quality of pigs 2. Mixing unfamiliar pigs
Authors: Guise H. J. , Penny R. H. C.
Published: September 2010

Mixing pigs from different social groups is known to cause turmoil which often results in skin lacerations as well as dark, firm and dry meat. Nine hundred and sixty commercial crossbred pigs were used for this experiment, divided into eight consignments. Within each consignment the pigs were divided into groups of about 15. The pigs in each group had coexisted for at least 6 weeks prior to slaughter. Thirty min before loading for slaughter, groups of pigs were either mixed with unfamiliar pigs or not mixed. Similarly, on arrival at the abattoir, groups of pigs were either mixed or not mixed. Hence there were four possible treatment combinations: pigs mixed with unfamiliar animals at loading, mixed at unloading, mixed at both points, or pigs which had remained in their social groups for at least 6 weeks prior to slaughter. Carcasses were dressed according to normal practice. After 20 h in the chiller room carcasses were assessed for skin blemish and fibre optic probe (FOP) values were measured in the longissimus dorsi muscle. Mixing pigs at either loading or unloading, or at both points, had no significant effect on the FOP value, but it did have a significant effect on the frequency of skin blemish values. Skin blemish values increased due to mixing at the farm (+0·36, Meat and Livestock Commission scale) however mixing at both places did not have an additive effect. The results indicate that the ideal movement system might be to keep pigs in their farm pen social groups until the point of slaughter.
A comparison between an early weaning and a more conventional system of rearing dairy calves
Authors: Castle M. E. , Watson J. N.
Published: September 2010

1. Two groups of 12 Ayrshire heifer calves were reared from birth to 14 weeks on two contrasting systems.

2. The conventionally reared group consumed 19 gal. of milk, 86 gal. of milk substitute and 195 lb. of calf meal (17·0% crude protein in dry matter) in 14 weeks whereas the early-weaned animals consumed 5 gal. of milk, 19 gal. of milk substitute and 259 lb. of early-weaning cubes (22·7% crude protein in dry matter) in the same period and were weaned from milk substitute at 5 weeks old. All the calves had unlimited access to dried grass (12·0% crude protein in dry matter).

3. The mean live-weight gain of the calves on the conventional system was 1·26 lb./day and of the early-weaned animals, 1·20 lb./day. These values were not significantly different.

4. None of the experimental calves had bloat or indigestion and there was only one minor outbreak of scour.

5. At the present day prices of the foods, the early-weaning system was the cheaper system both per day and per pound of live-weight gain.
The influence of social behaviour on experimental design in animal husbandry
Authors: McBride Glenorchy
Published: September 2010

Evidence of an effect of the peck order in poultry on the variation in productive characters under floor conditions is used as the basis of a discussion on the design of animal experiments.

Since these competitive effects increase the variation between animals penned together, the usual tests for the presence of pen effects between replicate pens are unsuitable. Replicates should be used in all experiments when treatments are allocated to pens of animals to provide an adequate measure of the experimental error.

Considerations of social behaviour are likely to be relevant in many types of animal experiments, both husbandry and breeding.

It is, however, emphasised that the amount of information available on such an important question is completely inadequate and that behaviour studies should be incorporated into all types of animal experiments to obtain such information.
Polyspermy of pig ova
Authors: Hancock J. L.
Published: September 2010

Of 168 pronucleate ova recovered from sows killed at varying intervals after mating (0, 24, 30 and 48 hours), 20 showed more than 2 pronuclei; 19 of these were recovered from sows in which mating was delayed until 30 to 48 hours after the onset of heat. Evidence is presented that polyspermic fertilisation is responsible for the appearance of ova with more than 2 pronuclei. It is concluded that delayed mating increases the frequency of polyspermic fertilisation in pigs and this might be a source of embryonic mortality in pigs inseminated artificially.
Effect of age at which lambs are castrated on carcass weight and quality
Authors: Joubert D. M.
Published: September 2010

Groups of Dorper lambs were castrated at three ages: shortly after birth, and at two and four months of age. All were slaughtered at an age of six months and the carcasses subsequently weighed, graded, measured and scored. The results indicate no marked differences in either weight or quality of carcass between the treatments. It is concluded that the operation can safely be carried out, depending upon circumstances, at any stage between birth and four months.
The influence on growth rate and slaughter characteristics of implanting fattening male hoggets with various levels of hexoestrol and diethylstilboestrol
Authors: Lamming G. E. , Stokes R. M. , Horspool D.
Published: September 2010

In three trials involving 288 hoggets the influence on growth rate of implanting 15 mg. hexoestrol or 12 mg. stilboestrol was compared. In one trial the influence of adding excipient to either stilboestrol or hexoestrol to increase the surface area of the implant was also assessed. Live-weight gain was calculated for each time interval after implantation and it was concluded that after approximately 140 days the influence of implantation had largely disappeared. For optimum benefit to live-weight gain implantations should be made approximately 100 days prior to slaughter.

In all trials, implantation with synthetic oestrogens resulted in extra daily live-weight gain, the increase for all animals amounting to 31% extra daily gain for hexoestrol and 26% for stilboestrol. The addition of excipient to the implant diminished the initial growth response and reduced the extra gain achieved.

Implantation with the synthetic oestrogens significantly increased the final live-weight on the farm, live-weight before slaughter and carcass weights when groups of animals from each treatment were slaughtered together.

Stilboestrol and hexoestrol implantation resulted in an extra 4·7 and 6·1 lb. full live-weight; 3·7 and 5·3 lb. empty live-weight and 1·3 and 2·8 lb. extra carcass weight respectively, compared to controls killed at the same time.

Where hoggets had received a high-plane diet, treatment did not affect killing-out percentage, but where the level of nutrition was lower a decrease of up to 1% was observed. In all trials treatment with the synthetic oestrogens resulted in an increase in pelt weight and in one trial this increase was up to 2 lb.

Implantation with hexoestrol and stilboestrol increased the size of the gut full and empty in two of the trials. The differences were reduced when the gut weights were corrected to 100 lb. empty live-weight. The weight of the thyroid gland or the total weight of the trachea, heart and lungs were not affected by treatment.

The approximate rate of uptake of hormone from a 12 mg. implant of stilboestrol was assessed by the decrease in the weight of dried tablet removed at slaughter from 30 to 200 days after implantation. The linear regression y (uptake in mg.)=3·029+0·039x (days from implantation) fitted the data best, giving an approximate average uptake over this period of 39 micrograms of stilboestrol per day.
A comparison of whole milk with buttermilk in the rearing of calves for veal. 1. Rearing and growth
Authors: Fraser J. D.
Published: September 2010

1. Twenty spring-born Friesian calves, housed indoors, were divided into two groups each of 10 calves. During their first three weeks all calves were fed alike on whole milk containing 3·5% butterfat. At three weeks of age calves in one group were changed to a diet consisting of reconstituted buttermilk powder which was made up to the same energy content as the milk. Up to the 30th day intake was gradually increased to 20% of body weight; thereafter till slaughter of the calves at approximately 200 1b. live-weight both groups were fed to appetite twice daily.

2. Calves in both groups grew well and differences between groups in growth rate, and age at slaughter, food consumption and food conversion, were all statistically non-significant.
A method of collecting faeces from ewes
Authors: Owen J. B. , Ingleton Jean W.
Published: September 2010

A Method of estimating grazing intake is essential for studies of feed utilisation in ewes under natural conditions. Since the ewe is a close and selective grazer, methods involving the cutting of comparable grazed and ungrazed areas of the pasture are unlikely to allow reliable estimation of pasture intake. It seems likely that only by a study of the faeces produced can reasonable estimation of individual intakes be made. The first requisite for such estimations is an accurate method of estimating faeces output. Sheep, with their relatively lower and drier faeces output, present fewer problems in total faeces collection than do cattle, which produce large quantities of faeces of a low dry-matter content. The collection of faeces, free from urine, presents a special difficulty in female animals.
The effects of two meal supplements on the progress of calves receiving autumn grass
Authors: Chambers D. T.
Published: September 2010

1. Three groups, each comprising four Hereford-cross and four Friesian half-sib male calves, were fed milk substitute and offered grass cut from autumn pastures. Two of the groups received meal supplements of similar energy value but differing in protein content. The third group received no meal supplement.

2. As the consumption of meal rose the intake of herbage dry matter decreased but total dry matter intake increased.

3. The effects of the two meals on the progress of the calves were similar but not apparent until after the first 6 weeks. The lack of response to the high protein content of one meal suggests that energy may be the limiting factor to growth of calves reared on autumn pasture.

4. Hereford-cross calves which did not receive a meal supplement tended to make the best live-weight gains during the subsequent grazing season, but no such recovery was made by the Friesians.
The influence of breed and sex on carcass characters of beef cattle bred in dairy herds
Authors: Latham J. O. , Rogers C.
Published: September 2010

During a survey of beef production in East Anglia carcasses of 163 Friesian, 87 Dairy Shorthorn and 45 Aberdeen-Angus × Friesian steers and 44 Aberdeen-Angus × Friesian heifers were measured and scored by visual assessment for fat development. They were also graded by the Ministry of Agriculture, Fisheries and Food.

Age data indicated that the Friesian steers were, on average, younger at slaughter than the other groups, but they were incomplete and comparison was based on carcasses of the same weight. The Dairy Shorthorn steers had higher mean values than Friesians in three of the carcass measurements taken. The Dairy Shorthorns had a higher average fatness score and a higher proportion of Grade A carcasses. Aberdeen-Angus × Friesian steers had lower mean values for measurements of the hind leg, higher fatness scores and a higher proportion of Grade A carcasses than either of the two pure breeds. Aberdeen-Angus × Friesian heifers had lower mean values for measurements of both fore and hind legs, higher fatness scores and a slightly higher proportion of Grade A carcasses than the steers.

The information gained by use of measurements and fatness scores explained, but did not materially add to, the assessment of the relative value of the groups of carcasses given by grade.
Progeny testing of bacon pigs at Wye college
Authors: Duckworth J. E. , Cooper M. McG. , Dunkin A. G. , Taylor J. M. , Holmes W
Published: September 2010

A report is given on a progeny testing scheme for bacon pigs which operated at Wye College from 1953 to 1957. Boars were brought to the unit, mated to a random selection of sows and 20 progeny (4 pigs from each of 5 litters) were individually fattened under standard conditions. Growth, feed efficiency and carcass measurements were recorded. The data were examined by analysis of variance. Significant differences in most characters were shown between sows, between boars and between tests. There was a progressive improvement in growth performance but not in carcass measurements from the earlier to the later tests. This was attributed in the main to improved management.

Differences within litters were small for carcass length but large for backfat measurements. Significant differences between boars could be detected but this was limited by small numbers of boars within tests and the high variability of some characters. The growth performance and carcass characteristics of female pigs were significantly better than for castrated males. Estimates of heritability were fairly high for most characters.

Disease incidence declined in the later tests. In earlier tests congestion of lungs associated with virus pneumonia was associated with a slight reduction in speed of growth and feed efficiency.

The results are discussed with particular reference to their contribution to the evaluation and utilisation of progeny testing on a national basis.
Copper sulphate as a growth stimulant for pigs: effect of composition of diet and level of protein
Authors: Lucas I. A. M. , Livingstone R. M. , Boyne A. W.
Published: September 2010

Thirty six individually-fed pigs were used in a within-litter comparison of the 6 treatments of a 3 × 2 factorial experiment. The pigs were about 9 weeks old at the start and were slaughtered as their individual weights reached about 200 lb.

Three types of basal diet were given with and without a supplement of CuSO4.5H2O included at 0·1% (250 p.p.m. added Cu).The diets were based on (1) barley and fish meal, with 17% crude protein for pigs up to 103 lb. live-weight and 15·4 % from then on, (2) maize and soya (extracted soya bean meal), with about the same levels of protein and (3) maize and soya, but with only 13·4% crude protein for pigs up to 103 lb. and 11·9% for pigs of 103 lb. to 200 lb. Daily feed allowances were determined from a fixed scale based on live-weight.

Pigs given the high-protein maize-soya diets grew more rapidly, required less feed per lb. gain and had fatter carcasses than those given the barley-fish meal diets. This was probably because of the higher TDN content of the maize-soya mixture.

Pigs given the low-protein maize-soya diets grew less rapidly, required more feed per lb. gain and had fatter carcasses with smaller ‘eye’ muscles than those receiving the high-protein maize-soya diets, these being the usual effects of an inadequate supply of total protein or of an essential amino acid.

CuSO4.5H2O4 added as 0·1% of each of the three types of diet improved growth rate before 103 lb. live-weight but had no consistent effect on feed conversion efficiency. Between 103 lb. and slaughter the copper sulphate did not affect performance on the barley-fish meal or high-protein maize-soya diet, but in the low-protein maize-soya diet it reduced feed conversion efficiency and rate of gain by 5%. Although this interaction was not statistically significant it agrees with an observation made in Florida and warrants further investigation.
The effect of variation of protein quality and protein level in diets on the performance of young pigs
Authors: Jones A. S. , Hepburn W. R. , Cadenhead A. , Boyne A. W.
Published: September 2010

1. A feeding trial was conducted on 64 individually-fed pigs given diets varying in crude protein content, and containing as a protein supplement either white-fish meal or groundnut meal alone, or groundnut meal with L-lysine monohydrochloride or DL-methionine or both.

2. Daily live-weight gain and feed conversion ratio of pigs given diets containing fish meal were best when the diet provided 18% crude protein on an air-dry basis (15·7% white-fish meal).

3. Additions of L-lysine monohydrochloride to a diet providing 18% crude protein and containing 21% groundnut meal as the main source of protein produced highly significant (P<0·001) improvements in daily gain and feed conversion ratio and these measures were not significantly different from those of pigs given the control (fish meal) diet which provided similar total lysine and crude protein levels. The white-fish meal diet containing 18% crude protein produced pigs whose half carcasses were of higher specific gravity (P<0·05) and rib cuts with more protein and less fat (each P<0·05) than did the groundnut meal diet at the same protein level.

4. DL-methionine did not significantly affect live-weight gain, feed conversion, fat or protein content of the rib cut or the specific gravity of the half carcass.

5. Pigs on a 12% crude protein diet containing groundnut meal supplemented with lysine grew at the same rate as pigs on an 18% crude protein diet in which no lysine supplement was added to the groundnut meal. Their rib cuts contained more protein and less fat.
The effects of undecorticated cotton cake added to a grass diet fed to sheep
Authors: Dodsworth T. L. , Ball C.
Published: September 2010

Results are given from two digestibility trials in which the following three diets were fed to sheep: (i) grass only, (ii) grass+5 oz. cotton cake daily, (iii) grass+10 oz. cotton cake daily.

In the first trial the average dry-matter content of the grass was low (approx. 14%), intake was low and the supplements were eaten in addition to the grass. In the second trial where the dry-matter content (approx. 20%) of the grass and the intake were higher, the cake supplements reduced herbage consumption.

The feeding of cake did not have any significant effect on the dry-matter percentage in the faeces but depressed the digestibility of the dry matter, crude protein, crude fibre and nitrogen-free extract in the diets including cake and reduced their starch equivalent and total digestible nutrient values.

No evidence was found to support the recommendation that undecorti-cated cotton cake should be fed to grazing animals.
The growth and carcass quality of bacon pigs reared to different weights at 56 days old
Authors: Boaz T. G. , Elsley F. W. H.
Published: September 2010

Two experiments are described to investigate the effect of different weights of pigs at 56 days of age on live-weight gain, efficiency of feed utilisation and bacon carcass quality.

1. In Experiment I a comparison was made between 32 pairs of weaners, reared on the sow, which weighed 31·0 1b. and 45·4 1b. respectively at 56 days of age. After separation into heavy and light groups the pigs were group fed to bacon weight.

The heavy weaners reached 200 1b. eighteen days earlier than the light weaners but this difference was due completely to the slower rate of growth to 50 1b. live-weight. The heavy weaners required 3·59 1b. of meal per 1b. live-weight gain from 56 days of age to bacon weight compared with 3·50 1b. for the light weaners but there was no difference in efficiency of feed utilisation during the period taken to grow from 50 to 200 1b. There were no significant differences between the carcasses apart from an increased flare weight in the light weaners.

2. In the second experiment both suckled and early-weaned pigs were reared to 30, 40 and 50 1b. at 56 days of age and then fed individually to 200 1b.

The number of days taken to reach 200 1b. was 168·6 for the 50 1b. pigs, 176·6 for the 40 1b. pigs and 182·1 for the 30 1b. pigs; there were no differences due to the methods of rearing. The efficiency of feed utilisation from 56 days to 200 1b. was not affected by method of rearing but as weight increased from 30 to 50 1b. at 56 days, the meal required for a pound of subsequent live-weight gain increased from 3·06 to 3·24 1b.

The number of days to increase from 50 to 200 1b. live-weight was 110·4 for the 50 1b. pigs, 109·3 for the 40 1b. and 106·3 for the 30 1b. pigs, again there being no differences due to the methods of rearing. There were no differences in efficiency of feed utilisation from 50 to 200 1b.

Neither weight at 56 days nor method of rearing markedly affected the quality of the carcass but there was an indication that 56-day weight caused greater differences in the early-weaned treatments than in the suckled treatments.
The prediction of lean percentage of pigs of bacon weight from carcass measurements
Authors: Buck S. F. , Harrington G. , Johnson R. F.
Published: September 2010

1. Carcass measurement and dissection data from 250 pigs reared at the stations of the National Pig Progeny Testing Board have been analysed to study the value of the carcass measurements in predicting the percentage lean in the carcass.

2. Differences between sexes in the carcass characteristics were generally larger than those between breeds. Gilts had a higher percentage of lean meat than the hogs, with larger eye muscle dimensions and smaller measurements of backfat thickness.

3. For pigs of the same breed and sex, the best predictions of leanness possible without cutting the carcass were derived from measurements of shoulder and minimum loin backfat (see Figure 1). Mid-backfat measurements improved the accuracy of prediction, but length and depth of carcass did not. The residual standard error in percentage lean at constant shoulder and minimum loin backfat was 2·66% of side weight overall but this was reduced to 2·28% by adjustments for breed and sex.

4. Measurements made after cutting the carcass at the last rib gave more accurate predictions of percentage lean than did the split carcass measurements. The residual standard error in percentage lean at constant B, C and K (see Figure 2) was 1·97 % of side weight overall, reduced to 1·88 % by adjustments for breed and sex.

5. The implications of these relationships in carcass grading and carcass evaluation generally are discussed.
Implications of genetic-environmental interaction in animal breeding
Authors: Dickerson G. E.
Published: September 2010

This report is an attempt to interpret evidence concerning geneticenvironmental interaction as it relates to the effectiveness of selection.

Methods of estimating genetic-environmental interaction were investigated with the conclusion that the standard analysis of variance is a satisfactory tool provided (1) the interaction component of variance is adjusted for important variation between environments in the scale of genetic effects and (2) the variance component for the average effects of genetic groups is recognised as equivalent to the average covariance of the same genetic group in different environments (i.e.) to include the real possibility of negative genetic correlation.

It is shown that (1) response to selection for improved average performance over varying environments (ΔGt) is proportional to the genetic correlation between expressions of the same genotype in different environments (rG), that (2) gain in ΔGi, from measuring performance inkenvironments is proportional toifktimes as many animals are tested, but toif total numbers per genotypic class (nk) are held constant, whereg2is heritability of individual variation within environments andrGis the correlation between the phenotypic expressions of the same genotype in different environments.

Evidence is presented that (1) variations among poultry-farm environments in California cause important, but largely unpredictable, shifts in ranking of genetic stocks for egg production, and (2) improved accuracy in measuring genetic differences in average performance across environments probably justifies utilising a sample of 5 to 10 farms representing the range of environments for which the stock is bred.