bluuebunny/crossref_metadata_2025 huggingface dataset:
The dependence of lean carcass composition on carcass fat, as assessed by multivariate shape/size methods
Authors: Seebeck R. M.
Published: September 2010

The relationship between the composition of the fat-free carcass and carcass fatness was studied by considering the relationship as one between two shape vectors, with the effect of size removed, using an extension of the multivariate linear least squares technique for studying multivariate allometry.

In two sets of data, one of dressed carcasses of cattle and the other of empty carcasses of lambs, the composition of the fat-free carcass (in terms of protein, water and ash) was significantly related to carcass fatness (P< 0·10 andP< 0·05 respectively). The consequences of this relationship to the study of the chemical composition of carcasses are discussed.

Examination of the relationship in more detail showed that the fatter carcasses were those with more protein and less water in their fat-free carcass, in both sets of data, and with more ash in the empty carcasses of lambs.
A note on supplementing whole oat grain with molasses, urea, minerals and vitamins
Authors: Bogdanovic B.
Published: September 2010

Two rations were prepared for sheep in which whole oat grain was mixed with molasses, urea, minerals and vitamins. Chemical analysis showed that the minerals had adhered to the grain and that there was little loss of minerals after one year of storage. The diets were readily consumed by sheep.
Growth and carcass traits of bulls and veal calves of continental cattle breeds 1. Growth and food conversion efficiency
Authors: Khalil H. , Pirchner F.
Published: September 2010

Between six and 11 twin pairs each of the breeds Braunvieh (BV), Fleckvieh (FV), Grauvieh (GV), Pinzgauer (Pi) and Friesians (Fr) were either treated uniformly or separated and fattened to veal or to yearling bull stage. The aim of the experiment was the comparison of Central European breeds and to investigate genotype × rearing system interaction both within and between breeds. Veal calves were slaughtered at about 120 to 150 kg live weight (proportionately about 0·13 of estimated mature weight of bulls) and yearling bulls at 410 to 460 kg live weight, corresponding to proportionately 0·38 of estimated mature weight. In general, the dual-purpose breeds had higher growth rates both absolute (AGR) and relative (RGR) and better food conversion ratios (FCR) than the dairy breed, Friesian, and this was true irrespective of whether correlations were made to constant age, weight, maturity (equal proportion of adult weight) or carcass fatness. However, the early-weaned Friesian calves grew fastest in the early phase of the growing period and this probably reflected their superior appetite.

Interactions between breeds and rearing system (bull v. veal) were significant for RGR and for maturity-corrected FCR which was mainly caused by shifting of the positions of BV and Pi.

The pooled genetic correlations between performance in the different fattening categories were considerably below unity. The twin-pair correlations indicated high heritabilities which are biased by contributions from dominance and maternal environment. While in data corrected to comparable maturity, AGR and RGR were highly positively correlated, their correlation became negative in agecorrected data. The correlations with FCR displayed an equivalent change with sign reversed. The correlations between wither height and heart girth with AGR were positive for age-corrected data but negative or barely positive, respectively, for data corrected to equal maturity. Again, FCR behaved similarly but with sign reversed.
Growth and carcass traits of bulls and veal calves of continental cattle breeds 2. Carcass composition
Authors: El-Hakim A. , Eichinger H. , Pirchner F.
Published: September 2010

Sibs of five to 11 twin pairs each of five breeds were either slaughtered as veal or as yearling bulls. Highly significant breed differences were evident in the carcass tissue proportions which could be explained on the basis of differences in the physiology of dairy and dual-purpose animals, the former depositing more fat and more bone than dual-purpose breeds. Among the dual-purpose breeds the carcasses of the Pinzgauer (Pi) tended to rank between the carcasses of the Fleckvieh (FV), Braunvieh (BV), Grauvieh (GV) and those of the Friesian (Fr).

The dual-purpose breeds FV, BV, GV had more meat in the hindquarter and in the shoulder than the FR while these in turn had more meat in the brisket and in the flank and shank muscles. Again the Pi group tended to rank between the aforementioned groups.

Within breeds, large differences between twin pairs indicated high heritabilities for carcass tissue proportions and ratios. The heritability of commercial cut proportions was fairly high but the genetic variance was small, the genetic coefficient of variation being less than 0-02. The different degrees of sexual maturity and of carcass maturity also caused differences in the distribution of meat in the carcasses of young male animals.

Significant mean squares for interactions between treatments and breeds, and genetic correlations of less than unity between performance of twin genotypes in veal and in bulls, indicated age and/or rearing system by genotype interactions between and within breeds for various slaughter traits.

Phenotypic correlations between various slaughter traits were low except where part-whole relationships were involved. It is suggested that slaughter at comparable maturity in the respective treatments was the cause of the weak connection between the traits.
Effects of age and its relationship with body size on reproductive performance in Scottish Blackface ewes
Authors: Gunn R. G. , Doney J. M. , Smith W. F. , Sim D. A.
Published: September 2010

On a hill farm, the reproductive performance of Scottish Blackface ewes increases annually with increasing age up to 6 years and is positively related to pre-mating live weight. A group of Scottish Blackface ewe lambs was, from 5 months of age, preferentially managed over a 2-year period to accelerate the achievement of mature size, in order to study the relative importance of age and size to reproductive performance. Ovulation rate and early embryo mortality of these ewes at 31 months of age were compared with those of adult ewes of similar body size and condition at 79 months of age which had been reared conventionally in the same hill flock. Two comparisons were made, one between different age groups in the same year and the other retrospectively between different ages of the same age group. In the first comparison, the adult ewes had a slightly greater reproductive response which suggested a small effect of age per se but there was also the possibility of a genetic difference. In the second comparison, there was no difference in ovulation rate or potential lambing rate per pregnant ewe, but a trend towards greater wastage of twin-shed ova in the heavier and fatter younger ewes again suggested a small effect of age. At both ages, however, these ewes performed close to their adult genetic potential which suggested that the treatment of the young ewes was sufficient to overcome most of the limitations associated with age or size. Reproductive performance normally associated with young animals is therefore mainly an expression of their size relative to their maturity and the removal of the size limitation by higher levels of nutrition and more rapid growth can largely eliminate their poorer performance.
The effect of source of nitrogen and level of its supplementation on the performance of growing-fattening bulls
Authors: Levy D. , Holzer Z. , Samuel V. , Bruckental I.
Published: September 2010

Two feeding trails were made and in both all the diets given contained about 11 MJ metabolizable energy (ME) per kg dry matter (DM).

In trial 1, diets containing three concentrations of crude protein (CP) were given to a total of 84 Friesian bulls in each of three stages of growth. They were, in stage 1 (150 to 250 kg live weight) 130, 145 and 160 g CP per kg dietary DM; in stage 2 (250 to 350 kg live weight) 110, 130 and 145 g CP per kg dietary DM; in stage 3 (350 kg to slaughter) 95, 110 and 130 g CP per kg dietary DM. In stages 2 and 3, the source of supplementary nitrogen at each CP concentration was either soya-bean meal or non-protein nitrogen (NPN) giving six combinations of concentration and source of dietary CP. Live-weight gains in stage 1 were 1·52, 1·60 and 1·58 kg/day respectively (P > 0·05). In the stages involving both concentrations and source of nitrogen (soya-bean meal in parentheses), the mean daily live-weight gains were (1·40), 1·38, (1·32), 1·34 (1·34) and 1·31 kg for stage 2 (F > 0·05) and (1·14), 1·14, (1.24), 1·16, (1·06) and 1·08 kg for stage 3 (P < 0·05), for the diets of 130, 145 and 160 g CP per kg diet respectively.

Trial 2 consisted of six stages of growth, the first five of 45 days duration and the sixth of varying length up to a predicted slaughter weight, and seven dietary treatments. Treatment 1 was a negative control (NC) with a dietary CP concentration of 90 g/kg DM. For the other six treatments two concentrations of dietary CP were given; 120 g/kg and 140 g/kg in stages 1 and 2 and 100 g/kg or 120 g/kg in stages 3 to 6. Dietary CP concentration was increased by the addition of NPN, fish meal or soya-bean meal. A total of 98 Friesian bulls were used with an initial average live weight of 185 kg. Daily gain of the NC group in the six stages of the trial was 0·86, 0·97, 101, 1·13, 1·07 and 1·00 kg for stages 1 to 6 respectively. From the results it was concluded that feeding NPN is not efficient at live weights lower than 250 kg and that there is no advantage to feeding fish meal over soya-bean meal in diets of medium energy concentration at live weights heavier than 250 kg.
Performance of British Landrace pigs selected for high and low incidence of halothane sensitivity
Authors: Simpson S. P. , Webb A. J. , Wilmut I.
Published: September 2010

Halothane positive and negative selection lines were established to estimate the effects of the halothane gene on performance in British Landrace pigs. Incidences of positive reaction diverged from 0·12 in the foundation generation to 0·93 in the positive and to 0·02 in the negative line in generation 4. Differences in litter productivity as a trait of the dam were estimated from a total of 399 positive × positive and negative × negative parity 1 and 2 matings in generations 1 to 4.

Compared with negative contemporaries, positive females showed non-significant reductions in litter size at birth (−0·10, s.e. 0·26) and at 42 days (−0·28, s.e. 0·26), accompanied by significant reductions in average piglet weights at birth (−0·11, s.e. 0·02 kg) and 42 days (−0·4, s.e. 0·2 kg). There were no differences in conception rate or adult live weights. A subsample of 69 parity 2 and 3 sows slaughtered 30 days after mating showed no significant difference in ovulation rate or embryo survival, but for positive dams the length of embryos was significantly reduced (−3·1, s.e. 1·1 mm).

The study suggests that the principal effect of the halothane gene was in reducing foetal growth rather than litter size. However, the phenotypic difference is expected to under-estimate the genetic difference between homozygotes, and it was not possible to distinguish the effects of dam and offspring genotypes. The present economic loss of roughly £4·70 per positive litter would be unlikely to justify elimination of the gene from a purebred maternal Landrace herd.
The effect of air filtration on air hygiene and pig performance in early-weaner accommodation
Authors: Carpenter G. A. , Cooper A. W. , Wheeler G. E.
Published: September 2010

The effects of an internal recirculating air filter on air hygiene and pig performance were studied using two groups each of 100 early-weaned pigs from a commercial herd. The two groups were housed in separate rooms under identical conditions except that one room contained a recirculating air filter. Five trials were carried out, but the same records were not kept in all trials. The air throughput of the filter was similar to the installed ventilation capacity (0·9 m3/s). The filter material nominally removed particles > 5 μm. Distribution ducts discharged the filtered air downwards over the pigs' lying area at a velocity of 0·3 m/s. At locations close to the pigs, the most representative proportional reductions of total particles, dust mass, and bacterial colony-forming particles were 0·58 (P< 0·01), 0·73 (P< 0·01), and 0·51 (P< 0·01), respectively. No differences in growth rate or health of pigs after 3 to 4 weeks were observed between the rooms but the pigs originating from the room containing the air filter reached a marketable state 6 to 8 days earlier than the control group pigs on the three occasions that this aspect was monitored (P< 0·0·01).
On the derivation of economic weights in livestock improvement
Authors: Smith C. , James J. W. , Brascamp E. W.
Published: September 2010

The use of profit equations for deriving economic weights (the value per unit improvement in a trait) in the genetic improvement of livestock has led to anomalies both in theory and in practice. These anomalies can be removed by imposing two conditions. One is that any extra profit from genetic change that can be matched by rescaling the size of the production enterprise should not be counted since it can be achieved without any genetic change. Only savings in cost per unit of product value should be included. The second condition is that changes that correct previous inefficiency in the production enterprise should not be counted. Thus, it is assumed that resources are efficiently used, and changes in output will require proportional changes in input. This means that fixed costs, like variable costs, should be expressed per unit of output, rather than as a fixed total enterprise cost. Improvement effort spent on traits that redress current inefficiencies in a production enterprise is of local and temporary value and is at the opportunity cost of improvement of other traits that save costs per unit of product value and are of permanent and general value. Application of these two conditions is shown to give economic weights that are identical on different bases; scaled output value, input or profit; fixed output value, input or profit; and zero profit. They were also equivalent to economic weights derived as the cost per unit product value from an economic efficiency index. The dilemma of different economic weights for different perspectives in production (unit of product, animal, producer, investor, and consumer) is also resolved.
Performance of young steers offered silage or thermo-ammoniated hay with or without a fish-meal supplement
Authors: Gibb M. J. , Baker R. D.
Published: September 2010

An experiment was carried out to examine the performance of young steers given basal diets of either silage or ammoniated hay ad libitum, with or without a daily supplement of fish meal, equivalent to 0·75 g/kg live weight, over 16 weeks. Serial slaughter of animals was carried out to examine changes in body composition during the winter feeding period and the subsequent grazing season.

There was no difference in the intakes of hay and silage organic matter over the 16 weeks of treatment. Despite the increased intake of nitrogen on the ammoniated-hay diet there was no increase in the rate of protein gain. By turn-out the steers given silage had higher empty body and carcass weights, and greater contents of fat and energy. The increased rates of empty body-weight, carcass, protein, water and energy gains achieved when the supplement was given were similar for both basal diets. There was no effect of winter feeding treatment on changes in body composition during the grazing period, so that at the end of the summer period the silage-fed animals still had heavier empty body and carcass weights. Attention is also drawn to the possible dangers of feeding hay treated with anhydrous ammonia at high temperatures to such cattle.
Effects of body condition, food intake and temporary calf separation on the duration of the post-partum anoestrous period and associated LH, FSH and prolactin concentrations in beef cows
Authors: Wright I. A. , Rhind S. M. , Russel A. J. F. , Whyte T. K. , McBean Alison J. , McMillen S. R.
Published: September 2010

An experiment was conducted to examine factors affecting the length of the post-partum anoestrous period and associated effects on LH, FSH and prolactin. Forty-six cows (24 Hereford × Friesian and 22 Blue-Grey) ranging in body condition score at calving from 1·50 to 2·75 were used. They were individually fed chopped barley straw and concentrate at either 50 (low) or 91 (high) MJ metabolizable energy per day from calving. At 34 days post partum half the cows were separated from their calves for 48 h. The duration of the post-partum anoestrous period was estimated from progesterone concentrations in thrice weekly blood samples. Blood samples were collected every 20 min for 10 h periods immediately prior to calf separation, during the last 10 h of calf separation and 1 week later. All samples were analysed for LH, and every third sample was analysed for FSH and prolactin.

There were no significant effects of genotype, feeding level or calf separation on the length of the post-partum anoestrous period. There was a negative association between body condition score at calving and the length of the anoestrous period, with each unit increase in body condition score reducing the anoestrous period by 43 (s.e. 20) days. There was some evidence that feeding level affected the number of thin cows (body condition score ≤2·25 at calving) which were still acyclic at the end of the experiment, but not the number of fat cows (body condition score ≥2·5 at calving).

FSH levels were not affected by any of the factors examined. Prolactin concentrations were higher in fatter cows, in cows on the higher level of feeding and in Blue-Grey cows. Prolactin concentrations decreased during the period of calf separation. Genotype and feeding level had no effect on LH concentration or LH pulse frequency. LH pulse frequency was increased (P < 0·05) during the period of calf separation, but there was no effect 1 week later. There was a significant positive relationship between LH puise frequency and body condition score at calving in two of the three sampling periods.

It is suggested that the effect of body condition on the duration of the post-partum anoestrous period i s mediated through effects on LH pulse frequency.
The effects of genotype and post-weaning nutrition on compensatory growth in cattle reared as singles or twins
Authors: Wright I. A. , Russel A. J. F. , Hunter E. A.
Published: September 2010

Thirty-five Charolais × Blue-Grey and Charolais × (Hereford × Friesian) weaned suckled calves which had been reared as either singles or twins and 19 single-reared Luing and Charolais × Luing weaned suckled calves were given silagead libitumsupplemented with either 0·75 or 2·5 kg rolled barley per day during the post-weaning winter. During summer the cattle continuously grazed perennial ryegrass swards. The high level of barley supplementation increased winter live-weight gain by 0·25 kg/day (P< 0·001). During summer the cattle from the low level of feeding gained weight at 0·09 kg/day (P< 0·05) faster than those from the high level of feeding. However, by the end of the summer grazing period the cattle on the low level of feeding were proportionately only 0·97 the weight of the animals on the high level of feeding.

During winter the performance of all genotypes was similar, but at pasture the Luing cattle gained less weight (P< 0·01) than the single-reared Charolais-cross genotypes.

Twin-reared cattle took 55 days longer to reach slaughter condition, but produced carcasses of equal weight and fatness to those from single-reared cattle.

The twin-reared cattle on the high level of feeding and the single-reared cattle on the low level of feeding attained a similar weight, body condition and ultrasonic backfat at turn-out. Thereafter, their herbage intakes and live-weight gains were identical suggesting that previous level of feeding per se is unimportant in determining an animal's subsequent intake and performance. Rather it is the body composition at a given age, irrespective of the pathway followed to attain that composition, that determines performance thereafter. It is also suggested that the inability of cattle to compensate for a reduction in level of nutrition during the first 3 to 4 months of life is due to the lack of potential for fat deposition, and there is thus limited opportunity for nutritional manipulation of body composition at that age.
Ovulation rate of Lincoln ewes at Bahia Blanca, Argentina
Authors: Iglesias R. M. Rodriguez , Giglioli C. , Latimori N. , Irazoqui H.
Published: September 2010

An experiment was carried out at Bahia Blanca (38°44' S, 62°10' W) to estimate the seasonal variation in ovulation rate and its components shown by Lincoln ewes of constant live weight.

Twenty-three 5-year-old ewes were subjected to nine 17-day observation periods which were evenly spaced within 405 days.

Percentage of ewes showing oestrus and ovulation, incidence of multiple ovulations and ovulation rate were estimated for each period by using vasectomized rams and performing iaparoscopies.

Traits showed a similar seasonality which was presumably induced by the natural light regime to which the ewes became exposed before and during each observation period.

A significant and periodic relationship was found between each trait and the number of days elapsed from the longest day.

The predicted maximum values for each parameter were reached about 40 days before the shortest day. Prior to and after this date both the percentage of ewes showing oestrus and ovulation and the incidence of multiple ovulations declined so that the expected ovulation rate values became zero for a period of about 3 months before the longest day.
An economic selection index for lean meat production in New Zealand sheep
Authors: Simm G. , Young M. J. , Beatson P. R.
Published: September 2010

An economic selection index was derived for terminal sire sheep breeds or strains, using physical and financial results from New Zealand export lamb-producing flocks. The aggregate breeding value of the index comprised carcass lean weight and carcass total fat weight. Index measurements were live weight, ultrasonic fat depth and ultrasonic muscle depth. Economic values used for lean and fat weights (NZ$5·65 and NZ$–1·2 per kg, respectively) were the change in profit per kg increase in lean or fat weight from that in the average carcass of lambs slaughtered in 1984/85. The s.d. of the aggregate breeding value was NZS3·20, and the correlation between the full index and the aggregate breeding value was 0·23. This correlation fell to 0·18, 0·15 and 0·07, respectively, when muscle depth or fat depth or muscle and fat depths were omitted from the index. Selection on the full index, or on the index omitting muscle depth was expected to lead to an increase in carcass lean weight and a slight decrease in carcass fat weight. Selection on the index omitting fat depth, or selection on live weight alone, was expected to lead to an increase in both fat and lean weights.
Amino acid and energy interactions in growing pigs. 3. Effects of sex and live weight and cereal on the responses to dietary lysine concentration when fed ad libitum or to a restricted food scale on diets based on wheat or barley
Authors: Giles L. R. , Batterham E. S. , Dettmann E. Belinda , Lowe R. F.
Published: September 2010

The responses of growing pigs to dietary lysine as influenced by sex (male and female) and cereal (barley and wheat) were investigated in an 8 × 2 × 2 factorial experiment involving 128 pigs. The basal barley-soya bean (13·4 MJ digestible energy (DE) per kg) and wheat-soya bean (14·1 MJ DE per kg) diets were offered ad libitum from 20 to 50 kg live weight. The eight dietary lysine concentrations were 70 to 140 g/kg in increments of 1·0 g/kg. The experiment was repeated with pigs given food according to a restricted scale. Performance in both experiments was assessed by multiple regression analysis based on data from successive 10-kg live-weight intervals. Analysis of variance was used to assess chemical carcass composition and retention of protein and fat after slaughter at 50 kg live weight.

Average daily DE intake (MJ) of pigs fed ad libitum was not significantly different for barley-based (27·4) and wheat-based diets (29·1). For pigs fed on a restricted scale, average daily DE intake was 18 MJ for barley-based and 17·5 MJ for wheat-based diets. The daily energy retained in the empty carcass, expressed as a proportion of daily DE intake, was proportionately 0·08 less for barley-based than for wheat-based diets irrespective of whether food was offered ad libitum (0·347 v. 0·379) or restricted (0·311 v. 0·337).

The average daily gain of females fed ad libitum was not affected by dietary lysine concentration. With males, the response of daily gain to lysine concentration was curvilinear, increasing to a maximum of 120 g dietary lysine per kg up to 40·3 kg and 7·0 g/kg at greater weights for both cereals. For pigs fed on a restricted scale the daily gain on barley diets increased linearly up to the maximum dietary lysine concentration (14 g/kg), while for those on wheat-based diets maximum daily gain occurred with a lysine concentration of 11·2 g/kg for males and 131 g/kg for females. Carcass P2 backfat (mean = 15·4 mm), carcass fat proportion (mean = 242 g/kg) and carcass protein retention (mean = 89 g/day) were not significantly affected by dietary lysine concentration from 7 to 14 g/kg when pigs were fed ad libitum. However, when pigs were fed at a restricted level carcass fatness decreased to a minimum at 12 g lysine per kg.
The effect of supplementing silage-based diets with soya bean and fish meals for finishing beef cattle
Authors: Steen R. W. J.
Published: September 2010

Two experiments have been carried out to examine the effects on the intake and performance of finishing beef cattle of supplementing grass silages (perennial ryegrass) of medium and high digestibility (MD and HD respectively) with either extracted soya-bean meal or fish meal. In each experiment, the two silages were supplemented with (1) barley (107 g crude protein (CP) per kg dry matter (DM)), (2) a mixture of barley and soya-bean meal (187 g CP per kg DM) and (3) a mixture of barley and fish meal (182 g CP per kg DM) in a 2 × 3 factorial design. The MD silages were supplemented with 4·5 kg concentrates per head daily in each experiment and the HD silages with 2·75 and 2·5 kg per head daily in experiments 1 and 2 respectively. In experiments 1 and 2 respectively the diets were offered to 72 and 60 castrated male cattle of late maturing breed type which were initially 455 (s.e. 3·6) and 484 (s.e. 3·2) kg live weight; the MD silages contained 642 and 652 g digestible organic matter (DOM) per kg DM, 119 and 114 g CP per kg DM, 72 and 68 g NH3N per kg total N, and the HD silages contained 698 and 724 g DOM per kg DM, 158 and 148 g CP per kg DM, 58 and 51 g NH3N per kg DM. In experiment 1 for the MD silages supplemented with concentrates 1, 2 and 3 and the HD silages supplemented with concentrates 1, 2 and 3 respectively silage DM intakes were 5·47, 5·29, 5·24, 6·86, 6·77 and 6·76 (s.e. 0·129) kg/day; carcass gains 0·76, 0·74, 0·72, 0·75, 0·75 and 0·79 (s.e. 0·011) kg/day; subcutaneous fat depths 6·8, 7·8, 8·0, 9·2, 7·2 and 7·1 (s.e. 0·59) mm and areas of m. longissimus 21·5, 21·7, 23·2, 21·5, 22·4 and 21·9 (s.e. 0·78) mm2/kg carcass weight. Corresponding values for experiment 2 were 6·12, 6·05, 6·18, 7·65, 7·53 and 7·36 (s.e. 0·235) kg/day; 0·82, 0·88, 0·83, 0·85, 0·89 and 0·83 (s.e. 0·042) kg/day; 8·1, 7·8, 7·5, 9·1, 8·3 and 7·4 (s.e. 0·77) mm; 22·8, 21·9, 21·9, 21·0, 21·9 and 21·7 (s.e. 0·79) mm2/kg carcass weight. It is concluded that supplementation of MD or HD grass silages with soya-bean or fish meals did not significantly affect the intake, performance or carcass fatness of finishing beef cattle although the carcasses of animals offered HD silage supplemented with barley tended to be fatter than those from the other treatments.
Frequency of the halothane gene in british landrace and large white pigs
Authors: Southwood O. I. , Simpson S. P. , Curran M. K. , Webb A. J.
Published: September 2010

The gene frequency of the halothane gene was estimated in nine British Landrace and Large White nucleus herds. Two hundred and sixty British Landrace and 186 Large White pigs purchased from these herd, to be used as foundation stock for a joint experiment on lean growth at the Physiology and Genetics Research Station, Edinburgh at Wye College, were test mated to homozygous halothane reactors (nn). One thousand six hundred and forty-six British Landrace and 1764 Large White offspring were given a 4-min halothane test at average ages of 76 and 50 days respectively. Maximum-likelihood estimates of the halothane gene frequency were 0·33 (s.e. 0·03) in British Landrace and 0·11 (s.e. 0·02) in Large White. Estimated proportions of reactors amongst heterozygotes (Nn) and halothane homozygotes (nn) were 0·00 and 0·70 in Large White, and 0·02 and 0·85 in British Landrace. There was significant heterogeneity between the herds for both breeds (P < 0·05). The proportion of halothane reactors in British Landrace herds has increased significantly (P < 0·05) from 0·13 in 1979 to 0·18 in 1982, and the proportion of Large White reactors has increased from zero to 0·01 in the same time period.
The effects of sex and live weight on the growing pig's response to dietary protein
Authors: Campbell R. G. , Taverner M. R. , Curic D. M.
Published: September 2010

Thirty-two entire male and 32 female pigs were used to investigate responses to eight concentrations of dietary protein, with constant amino acid composition ranging from 90 to 248 g/kg over different live-weight stages between 20 and 90 kg.

With increasing live weight there was a continuous decline in the concentrations of dietary protein required to support maximum growth and an increasing difference between the sexes in their response to dietary protein. Between 20 and 40 kg live weight sex had no significant effect on growth performance or on the dietary protein concentration for maximum growth (P > 0·05). Over all heavier live-weight stages entire males grew faster and more efficiently than females, and between 20 and 70, 20 and 80, 20 and 90 and between 50 and 90 kg live weight they responded to higher concentrations of dietary protein than females. During the latter stages of growth, the performance of females was also depressed on the two highest-protein diets. This was associated with a significant increase in carcass fat thickness at 90 kg.
Effect of multiple suckling in early lactation on the performance of May-born calves
Authors: Chestnutt D. M. B.
Published: September 2010

In three experiments, 16, 24 and 22, May-calving Aberdeen Angus × British Friesian cows were subjected either to single suckling of their natural calves or to single suckling in addition to ‘foster’ suckling for the first 8 to 9 weeks of lactation. Foster suckling was achieved by the removal of cows from pasture twice daily and suckling of male Friesian calves while cows were confined in a creep. Average milk yield per cow removed by foster suckling and milk secretion rates of individual cows were measured at intervals and cows were grazed at equal grazing pressure. Single plus foster suckling increased estimated total yield over single suckling proportionately by 0·55, 0·18 and 0·34 in the three experiments respectively. After foster calves were weaned, milk secretion rate of foster-suckling cows was always higher than that of naturally suckling cows. In addition to a mean yield of about 300 kg milk per cow to foster calves, single plus foster suckling increased calf gain in the natural calves in each experiment although the increases were not significant. The apparent conversion of extra milk consumed by natural calves in the single plus foster suckling treatment was generally low in relation to figures quoted in the literature.
A note on dry-matter intake and composition of gain of Simmental bulls and steers fed to the same weight or age
Authors: Anderson P. T. , Hawkins D. R. , Bergen W. G. , Merkel R. A.
Published: September 2010

Differences in dry-matter intake and composition of gain between 35 Simmental bulls and 35 Simmental steers were examined. All bulls and 15 steers were slaughtered after 167 days on food and the remaining steers were slaughtered after 224 days. Bulls ate more food daily than steers (P < 0·1) but drymatter intake per unit of metabolic body weight (kg M0·75) was not different between groups (T > 0·1). Bulls had greater estimated rates of protein accretion than steers (P < 0·001) but estimated fat accretion rates were not different. These data suggest that voluntary food intakes do not differ between bulls and steers of equal weight and indicate that bulls are leaner than steers due to greater lean tissue accumulation rather than less fat deposition.
Effect of age on energy utilization of early-weaned growing calves weighing less than 100 kg
Authors: Sekine J. , Oura R. , Morita S. , Morooka T. , Asahida Y.
Published: September 2010

To study, after weaning at 6 weeks of age, the effect of age on energy utilization of growing calves and to estimate the requirements of metabolizable energy (ME) for calves weighing less than 100 kg, 243 energy balance trials were conducted using 68 Holstein-Friesian castrated male calves at 7, 9 and 13 weeks of age. Regression analyses of energy retention (ER, kj/kg M0·75) on intakes of ME (kJ/kg M0·75) gave the following equations at the respective age: ER = 0·479 (s.e. 0·070) ME — 197, for 7 weeks, ER = 0·521 (s.e. 0·052) ME - 216 for 9 weeks and ER = 0·523 (s.e. 0·043) ME - 236, for 13 weeks. Amounts of ME for maintenance (MEm) calculatedas ER = 0 were 413, 415 and 451 kJ/kg M0·75 for calves at 7, 9 and 13 weeks of age, respectively. The efficiency of utilization of ME for growth was not significantly different among the ages and was 0·500 (s.e. 0023). ME required for growth was estimated to be 510 kJ/kg M0·75 for each kg gain in weight, irrespective of age. The requirements of ME of calves weighing less than 100 kg were lower than those estimated by extrapolation of British and American standards.
Eating and ruminating behaviour in cattle given forages differing in fibre content
Authors: McLeod M. N. , Smith B. R.
Published: September 2010

A study was made of the effect of fibre level in forages on eating and rumination behaviour. Eight forage diets were prepared from the leaf and stem fractions of two grasses and two legumes and were given at hourly intervals to four steers under steady-state conditions. Eating and rumination behaviour were measured automatically by recording changes in intra-oesophageal pressure.

Mean voluntary intake of leaf was higher than that of the stem fractions (9·9 v. 5·6 kg/day; P < 0·001). This was associated with a shorter mean retention time in the rumen of the leaf than that of the stem fractions (21·4 v. 30·6 h; P < 0·001) and a lower concentration (g/100 g dry matter (DM)) of fibre (52-0 neutral-detergent fibre (NDF) and 30·5 acid-detergent fibre (ADF) v. 68·2 NDF and 45·3 ADF). Similar values (P > 0·05) between diets were found for both the water and DM contents of the rumen (60·1 kg, 7·8 kg). Voluntary intake was not related to either.

No difference was found between forage diets in the mean time (132 min) and number (18·7) of periods spent eating each day (P > 0·05). Legume leaf fractions were eaten at a faster rate (g/min) than either the grass leaf or the stem fractions. Voluntary intake was related to the rate at which food was eaten (r = 0·89; P < 0·01) but no relationship was found with the time taken to eat food (r = –0·14; P>0·05). Eating rate was related to the level of both NDF (r = –0·91; P < 0·01) and ADF (r = –0·96; P < 0·001).

Differences between diets were found in rumination times (mean 425 min; P < 001), the number of boluses regurgitated during each period (27·6; P < 0·05) and during each day (485; P < 0·001), and in the weight of boluses (455 g; P < 0·05). No differences (P > 0·05) were found between diets in the mean number of rumination periods each day (17·6), the mean time spent ruminating during each period (24·3 min), the mean rate at which boluses were regurgitated (53·2 s per bolus), the interval between boluses (5·1 s), and the DM in a bolus (27·5 g). Rumination time and the number of boluses regurgitated either per period or per day were not related to the fibre content of the diet (P > 0·05).

The regurgitated boluses from leaf fractions were chewed less than the stem fractions (43·7 v. 54·7 chews per bolus). The regurgitated boluses of lucerne leaf were chewed at a faster rate (1·13 chews per s; P > 0·05) than regurgitated digesta of the other diets which were chewed at similar rates (0·97 chews per s; P > 0·05). The total number of rumination chews made each day by animals given lucerne leaf (12 300) was much lower (P < 0·001) than that by animals given the other fractions (25 300). The number of chews made on each bolus was related to fibre levels in the diets (NDF, r = 0·78, P < 0·05; ADF, r = 0·91, P < 0·01).

It is concluded that the voluntary intake of high-fibre diets is not always restricted by rumen fill or rumination. The ease with which forage is eaten should be investigated as a factor influencing intake of fibrous forages.
A note on the effects of the method of inclusion of sodium bicarbonate and diet composition on the intake of diets based on silage by dairy cows
Authors: Newbold C. J. , Thomas P. C. , Chamberlain D. G.
Published: September 2010

Sodium bicarbonate had no effect on the dry-matter (DM) intake of heifers given a complete mixed diet of grass silage, molasses, barley, soya-bean meal and a mineral mix (660, 140, 100, 85 and 15 g/kg DM respectively) when it was incorporated into the mix at 20 and 40 g/kg DM or sprinkled on top of the diet at a rate of 350 g/day. In a second experiment, cows in mid lactation were given a complete mixed diet of silage, barley, soya-bean meal and minerals (660, 240, 85 and 15 g/kg DM) or the same diet with the barley replaced with molasses at 140 g/kg DM. Sodium bicarbonate was sprinkled on top of the diets at 0, 450 or 900 g/day. There were no significant effects on DM intake in the final week of each 3-week period. However, there was an apparent interaction of diet and sodium bicarbonate on the initial acceptance of the diet, with the intake of the diet in week 1 being significantly lower than the final intake with 900 g/day sodium bicarbonate in the absence but not in the presence of molasses.
Quality and colour of melatonin—and bromocriptine-induced winter fur growth in mink (Mustela vison) given a supplemented diet
Authors: Slayden O. D. , Adair J. , Stormshak F.
Published: September 2010

An experiment was conducted to evaluate the effects of diet on fur colour and quality of bromocriptineand melatonin-induced winter pelage in mink. At weaning, 90 standard dark female kit mink were assigned randomly to one of two dietary regimens. Diet 1 (no. = 30) was a basal ranch mink diet, and diet 2 (no. = 60) was the basal diet, supplemented with liver and eggs. On 26 June 1986, mink given each diet were assigned to treatment (no. = 15) and control groups (no. = 15). Animals receiving diet 1 were treated with 120 mg melatonin implants (silastic) while those given diet 2 were treated with 120 mg melatonin implants, 60 mg bromocriptine pellets, or 60 mg bromocriptine pellets plus 18·6 mg melatonin implants (silastic). Control groups on each diet received no implants. Subsequently, fur growth was measured at biweekly intervals. Mink treated with 120 mg melatonin, 60 mg bromocriptine, and 60 mg bromocriptine plus 18·6 mg melatonin all moulted 1 month earlier than controls and exhibited significantly greater fur growth during the months of August and September (P < 0·05). Mink implanted with 120 mg melatonin, and bromocriptine plus melatonin were considered to be in fully prime pelage by mid October and were pelted by October 23. Mink receiving bromocriptine alone were not considered to be in prime pelage in October and were pelted in December with controls. Neither diet supplementation with liver and eggs, nor treatment to induce early fur growth had an effect on fur colour or quality. It was also concluded that treatment of mink with bromocriptine may not completely mimic the effect of exogenous melatonin on winter fur growth.
A note on the induction of ovulation in lactating red deer hinds prior to the breeding season
Authors: Fisher M. W. , Fennessy P. F. , Davis G. H.
Published: September 2010

Methods of inducing ovulation 3 weeks prior to the onset of the breeding season were evaluated in lactating adult red deer. Following 11 days of intravaginal progesterone pre treatment, hinds were either untreated (control), or given 300 i.u. PMSG i.m. or 500 mglh GnRH s.c. by osmotic pump. All hinds were laparoscoped 7 days after progesterone withdrawal to record the presence or absence of a corpus luteum on the ovaries, Laparoscopy showed 0113 control, 11113 PMSG and 8/13 GnRH-treated hinds ovulated indicating that during lactation, both methods of inducing ovulation are similarly effective, However, although these treatments induced ovulation, fertility as assessed from calving records, was poor.
A note on the live-weight growth in indigenous nigerian pigs
Authors: Essien A. I. , Fetuga B. L.
Published: September 2010

Live-weight growth was studied for 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs at 16 ages from birth to 672 days. The weights obtained were fitted into four different growth functions to derive prediction equations for the models used. The quadratic (W = a + bt + ct2) and the Schmalhausen functions (W = at) described live-weight growth better than the simple linear function fW = a + bt). Estimating live-weight growth using Brody's function (Y = aebt) gave the least exact predictive ability. Linear growth in indigenous Nigerian pigs occurred between 112 and 336 days. Castrated male pigs exhibited higher live-weight growth rates than either the female or intact male pigs. Differences in the prediction of live weights using the four growth functions and the actual live weights are presented and discussed.
A note on the seasonal oestrous period in three breeds of Greek dairy sheep
Authors: Vosniakou A. G. , Doney M. , Tsakalof P.
Published: September 2010

Fourteen adult ewes from each of three breeds, Karagouniko (K), Serres (S) and Chios (C), were maintained, barren, as a single flock at Diavata (latitude 40·5°N) for 2 years. Oestrus was checked twice daily by vasectomized rams for 17 months from April 1979. For K, S and C ewes, respectively, the mean dates of onset were 7 August (s.e. 6·5), 31 July (s.e. 8·2) and 28 July (s.e. 7·3) (P < 0-05) and the spread of first oestrus extended to 100, 94 and 95 days, respectively. Over all breeds, the dates of first oestrus ranged from 23 May to 19 September. Mean dates of last oestrus were 16 April (s.e. 8·5), 5 April (s.e. 9·5) and 20 May (s.e. 7·0) (P > 0·01) and the mean durations of the breeding period were 253 (s.e. 11·0), 247 (s.e. 12·2) and 301 (s.e. 10·2) days, respectively (P > 0·01). In the second season, the mean dates of first oestrus were 4 September (s.e. 2·4), 28 August (s.e. 5·1) and 25 July (s.e. 6·2), respectively (P < 0·01).
A comparison for live weight and carcass production of Charolais, Hereford and Friesian steer progeny from Friesian cows finished on two energy levels and serially slaughtered
Authors: More O'Ferrall G. J. , Keane M. G.
Published: September 2010

One hundred and sixty-two spring born steers comprising 54 Charolais × Friesian (CH), 54 Hereford × Friesian (HE) and 54 Friesians (FR) were reared together from shortly after birth until the end of their second grazing season at a mean age of 573 days. The animals were then blocked on weight within genotype, housed in a slatted shed and allocated to either a high (12·6 MJ metabolizable energy (ME) per kg) or a medium (10·4 MJ ME per kg) energy diet offered ad libitum until slaughter at one of three target carcass weights · light (260 kg (HE, FR and CH)), normal (300 kg (HE and FR) and 320 kg (CH)) or heavy (340 kg (HE and FR) and 380 kg (CH)) to give a 3 (breed type) · 2 (energy level) · 3 (slaughter weight) factorial arrangement during the finishing winter. The trial was repeated in 3 years consecutively.

CH were significantly heavier than HE at all times up to 18 months of age when they were 43 kg heavier, at which stage they were also 24 kg heavier than FR. CH grew significantly faster at pasture than HE in both seasons and faster than FR in the second season. HE had the best daily gain in the finishing period.

Overall slaughter weights per day of age, carcass weights per day of age and carcass weights of CH, HE and FR were 812, 771 and 761 (s.e. 9·2) g, 448, 418 and 405 (s.e. 4·8) g and 318. 299 and 298 (s.e. 2·2) kg, respectively. CH had significantly better killing-out proportions (lOg/kg) than HE which in turn were 10 g/kg better than FR. CH and FR had similar carcass length, carcass depth, leg length and leg widths and both were significantly larger than HE. CH had significantly larger longissimus dorsi areas than either HE or FR (80·9 v. 67·0 and 66·4 cm-); they also had significantly better conformation scores than HE which in turn were significantly better than FR.

Increasing the energy level during the finishing period increased daily gain by proportionately 0·52 (1089 v. 684 g/day), reduced slaughter age by 51 days (711 v. 762 days) and significantly increased killing-out proportion (551 v. 534 g/kg) and conformation score (4·86 v. 4·64). Offal as a proportion of empty live weight tended to be higher for FR than for HE or CH, the exception being the hide, which was significantly lower for FR.
The growth to maturity of lean and fat lines of broiler chickens given diets of different protein content: body composition, plasma lipoprotein concentration and initial egg production
Authors: Whitehead C. C. , Armstrong J. , Herron K. M.
Published: September 2010

The proportions of abdominal fat and total body lipid and protein were measured up to 30 weeks in males and 21 weeks in females from lines of lean and fat broiler chickens given diets of different protein content. There was a constant relationship between the proportions of abdominal fat and body lipid independent of line, diet or age. Data on males showed effects of line and diet on body fatness at all ages up to 30 weeks. In females, line and diet had effects on body fatness during early growth but little effect on composition at 21 weeks. Plasma very low density lipoprotein concentration was higher in the fat line in both sexes at all ages. Egg production over the first few weeks of the laying period was much higher in lean line hens.