bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ovulation rate of Lincoln ewes at Bahia Blanca, Argentina
Authors: Iglesias R. M. Rodriguez , Giglioli C. , Latimori N. , Irazoqui H. 
Published: September 2010

ABSTRACTAn 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

ABSTRACTAn 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

ABSTRACTThe 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

ABSTRACTTwo 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

ABSTRACTThe 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

ABSTRACTThirty-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

ABSTRACTIn 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.
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

ABSTRACTTo 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

ABSTRACTA 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.
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

ABSTRACTAn 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 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

ABSTRACTOne 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

ABSTRACTThe 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.
Comparison of theoretical and simulated equilibrium genetic response rates with progeny testing in dairy cattle
Authors: Meyer Karin , Smith C. 
Published: September 2010

ABSTRACTThe published theoretical estimates of equilibrium genetic change possible by progeny testing in dairy cattle are too high. Much of the overestimation is because no account has been taken of the temporary reduction in genetic variation due to selection of parents and ancestors. A particular efficient progeny testing scheme was modelled theoretically and simulated on computer using a continuous infinitesimal additive model. To make the simulation feasible an elite breeding herd of females was used, and progeny testing was done outside the herd. The proportional reduction in genetic variance due to previous selection was 0·25, 0·27 and 0·29 for original heritabilities of 0·05, 0·25 and 0·50, with the theoretical and simulated results being very similar. The theoretical and simulated proportional losses in equilibrium selection responses were 0·22 and 0·26, 0·21 and 0·22 and 0·21 and 0·25, respectively, for the three levels of heritability. Thus, most of the loss in response in the simulation results came from the reduction in genetic variance due to selection.