bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of level of barley supplementation on the performance of continental × Holstein Friesian bulls given grass silage
Authors: Grundy H. F. , Hardy R. , Davies M. H. 
Published: September 2010

AbstractForty Charolais and 40 Limousin × Holstein Friesian bulls, 8 months old and weighing 315 kg live weight at the start of the experiment, were given grass silage to appetite throughout.From 315 to 425 kg live weight they received: no supplement (S0), 1 kg (S1), 2 kg (S2) or 4 kg (S4) of a rolled barley supplement per head per day. After a mean treatment live weight of 425 kg had been achieved for each breed, the daily supplement of all treatments was changed to 3 kg of rolled barley per head per day until individual animals were adjudged to have attained a European Community (EC) external fatness score of 3 to 4L, at which point they were slaughtered.Daily growth rates from 315 to 425 kg live weight were 0·67, 0·82, 0·94 and 1·25 (s.e.d. 0·042) kg for treatments S0, S1, S2 and S4 respectively. Following the change of supplement rate at 425 kg live weight, daily gains were 1·46, 1·36, 1·27 and 1·16 (s.e.d. 0·051) kg/day, giving overall gains of 0·99, 1·05, 1·08 and 1·19 (s.e.d. 0·033) kg/day respectively. The numbers of days taken to achieve slaughter condition from the start of the trial at 315 kg were 277, 251, 243 and 207 (s.e.d. 5·3) days respectively. Bulls were slaughtered at 17·0, 16·2, 15·9 and 14·7 months of age and produced carcass weights of 330, 324, 322 and 305 (s.e.d. 6·5) kg respectively.Silage dry-matter intakes were 5·9, 5·1, 4·8 and 4·2 kg/day during the initial phase when differential supplement levels were being given and 7·0, 6·8, 6·2 and 5·8 respectively during the finishing period when all groups were being given 3 kg barley supplement daily. Food conversion ratios (kg dry matter intake per kg gain) were 9·1, 7·3, 6·9 and 5·8 during the initial phase and 6·4, 6·9, 6·9 and 7·2 respectively after 425 kg live weight.It is concluded that barley supplements of 0 to 2 kg/day offered with high-quality grass silage during the growing stage (8 to 12 months of age), followed by at least 3 kg/day will produce finished bulls at an average of 325 kg carcass weight at 16 to 17 months of age. A higher level of 4 kg barley during the growing stage will reduce the slaughter period to approximately 15 months of age but carcass weight will also be reduced. Further studies are required to define the precise level of barley supplement during this earlier period.
The effects of forage type (maize-lablab or oat-vetch) and level of supplementation (wheat-middlings) on food intake, diet apparent digestibility, purine excretion and milk production of crossbred (Bostaurus × Bos indicus) cows
Authors: Khalili H. , Osuji P. O. , Umunna N. , Crosse S. 
Published: September 2010

AbstractAn experiment was carried out to evaluate the effects of forage type and level of concentrate supplementation on forage intake, diet apparent digestibility, purine excretion and milk production. Twelve crossbred cows (Bos taurus × Bos indicus), in early lactation, were allocated to the following six dietary treatments: maize-lablab forage (ML) or oat-vetch forage (OV), offered ad libitum, and supplemented with either 0, 2·5 or 5·0 kg per cow per day of a supplement (wheat middlings). A four-period, partially balanced, change-over design was used and the treatments were arranged as 2 × 3 factorial.Mean organic matter (OM) intake was 670 g higher with cows on ML-based diets compared with those on OV-based diets (P<0·02). The apparent digestibilities of crude protein (CP) and neutral detergent fibre (NDF) were similar for cows given ML- or OV-based diets but the apparent digestibility of OM was higher for ML diets (P<0·05). Values of the degradation parameters (a, b and c) of DM and NDF were greater for ML forage than for the OV forage. Forage type did not affect daily milk yield nor excretion of purine derivatives in urine used to estimate microbial-nitrogen supply (P >0·05). The concentration of milk fat and total solids in the milk were similar for the two forage types offered but the concentration of milk protein was slightly higher for the cows given ML-based diets (P<0·05).Daily OM intake increased by 3·75 and 2·70 kg per cow per day (P<0·001) respectively, when the amount of concentrate increased from 0 to 5·0 kg per cow per day for the ML- and OV-based diets. The CP apparent digestibilities of the diets were higher when the diets were supplemented with concentrates but there was no effect of supplementation on the apparent digestibilities of OM and NDF. The supply of microbial-nitrogen increased linearly with increasing level of concentrate supplementation (P<0·05). Milk yield increased linearly when the level of concentrate supplement increased from 0 to 5 kg (P<0·001), resulting in 0·39 and 0·29 kg more milk per day per kg additional concentrate given in cows on ML and OV, respectively. There was also a tendency for a quadratic effect (P<0·12), especially with ML diets, showing that when the level of concentrate increased from 0 to 2·5 or from 2·5 to 5·0 kg/day, the milk yield increased respectively by 0·62 and 0·15 kg/day per kg additional concentrate given.
Effect of breed type, sex and method of rearing on lifetime performance and carcass composition in a 20-month beef system: effects of winter feeding treatments
Authors: Lowman B. G. , Hunter E. A. , Hinks C. E. , Lewis M. 
Published: September 2010

AbstractIn the winter feeding phase of a lifetime study of spring-born cattle managed in a 20-month beef system, a total of four feeding treatments were imposed by increasing the level of concentrate supplement offered with ad libitum grass silage. The objective was to achieve a difference in live weight at the end of the winter of about 25 kg between food treatments. A multifactorial design was used with three animal factors — maturity (early maturing Hereford crosses v. late maturing Charolais crosses), sex (heifer v. steer) and method of rearing (suckled calves v. bucket-reared calves).There were no significant differences between breeds but highly significant (P < 0·001) differences for method of rearing and sex. As a consequence live-weight differences at the end of the winter between breed types (18 kg) were less than the difference between the sexes (23 kg) and for method of rearing (25 kg) although all were highly significant. Although suckled animals had significantly lower growth rates they were still significantly fatter at the end of the winter as were heifers and Hereford crosses. Differences in dry-matter intake were reflected in growth rate.Plane of winter nutrition had a highly significant effect (P < 0·001) on live weight and condition score at the end of the winter resulting in increments of about 23 kg and 0·12 units of condition for each level of feeding.Interactions between the main production variables were not significant with the exception of feeding level and method of rearing. Suckled animals showed a significant (Y < 0·001) reduction in winter gain (proportionately 0·85 for that of bucket-reared animals) when offered the same diet. This reduction ranged proportionately between 0·25 and 0·08 for the lowest and highest daily levels of concentrate supplementation respectively. An extra 1 kg concentrates per day was required for suckled animals to achieve similar live-weight gains to bucket-reared animals.
The effect of immunoneutralization of PMSG near a gonadotropin-induced oestrus on the reproductive performance of gilts
Authors: Kirkwood R. N. , Peacock A. J. , Van Lunen T. A. , Thacker P. A. 
Published: September 2010

AbstractIn four experiments, 189 gilts either received PMSG antiserum around the time of a PMSG- (experiments 1, 2 and 3) or PMSG/hCG-induced (experiment 4) oestrus or served as controls. Ovulation rates were not affected by treatment. There was no treatment effect on pregnancy rate (experiments 2, 3 and 4). In experiment 2, numbers of embryos in PMSG-treated control gilts were quite low and were higher (P < 0·05) in those gilts subsequently receiving anti-PMSG treatment. In experiment 3, the mean number of embryos in control gilts were higher than in experiment 2 and there was no effect of immunoneutralization of PMSG. No treatment effect was evident in PMSG/hCG treated gilts (experiment 4). These data indicate that the immunoneutralization of PMSG is unlikely to improve the reproductive performance of gilts following a gonadotropin-induced oestrus except in gilts that otherwise would have poor performance.
Effect of chemical structure of fats upon their apparent digestible energy value when given to young pigs
Authors: Powles J. , Wiseman J. , Cole D. J. A. , Hardy B. 
Published: September 2010

AbstractThe effect of degree of saturation (ratio of unsaturated to saturated fatty acids, U/S) and free fatty acid (FFA) content of fats upon their digestible energy (DE) values was investigated in post-weaning pigs. The two fats evaluated were soya-bean oil (SO) and tallow (T) (representing extremes of saturation) together with their acid oils (SAO and TAO respectively) providing high FFA levels). Blends of the four fats provided treatments with varying FFA content and U/S ratios. The experimental fats were evaluated by substitution, at 40, 80 and 120 g/kg into a basal diet, in a randomized-block design, with 98 gilts and 98 boars of approximately 12 kg live weight. Pigs had been weaned at 28 days of age and experimental diets were given 7 days after weaning. When pigs obtained a weight of 10 kg the inert marker titanium dioxide was added to the diets as a reference substance. A 5-day adjustment period was allowed followed by a 5-day collection period of faeces by grab sampling. Fat content of food and faeces, with methodology based on acid hydrolysis, allowed calculation of apparent digestible fat (AFD) of experimental diets. Analysis of variance demonstrated effects of fats, rates of inclusion, and fats × rates (P < 0·001 in all cases). There was no effect of sex. Extrapolation of the function obtained by regressing AFD of diets (y) on rate of inclusion of fat (x) to × = 1000 generated values for the fats. The product of the coefficient of fat apparent digestibility of fats and their respective gross energies gave DE values for fats which were: SO = 37·2 MJ/kg, SAO = 35·0 MJ/kg, T = 34·3 MJ/kg and TAO = 27·4 MJ/kg. Data for fat blends intermediary between these fats showed that DE improved as a function of U/S and that DE declined linearly with increasing FFA content.
Selection for components of efficient lean growth rate in pigs 1. Selection pressure applied and direct responses in a Large White herd
Authors: Cameron N. D. 
Published: September 2010

AbstractResponses to four generations of divergent selection for lean groivth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Large White pigs were studied. The LGA (LFC) selection criterion was designed to obtain equal correlated responses in growth rate (food conversion ratio) and carcass lean content, measured in phenotypic s.d. The selection criteria had phenotypic s.d. of 27, 29 and 253 units, respectively, and results are presented in s.d. units. There was a total of 3537 pigs, with an average of 40 boars and 40 gilts performance tested in each of the high, low and control lines per generation and the lines consisted of 10 sires and 20 dams. The generation interval was equal to 13·5 months. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively.Cumulative selection differentials in the three selection groups were 5·8, 3·6 and 3·3 phenotypic s.d. for LGA, LFC and DFI respectively. Direct responses to divergent selection were 1·7, 1·3 and 1·2 (s.e. 0·17) for LGA, LFC and DFI. The correlated response in LFC (1·6 (s.e. 0·18)) with selection on LGA was greater than the direct response in LFC. Conversely, the direct response in LGA was greater than the correlated response (1·1 (s.e. 0·18)) with selection on LFC. The response in LFC (–1·1 (s.e. 0·17)) with selection on DFI was similar in size but opposite in sign to the direct response in LFC. Responses were asymmetric about the control, as the high LGA and LFC responses were proportionately smaller (0·74 and 0·58) than low line responses. In contrast, the difference between the high DFI and control was four times greater than the difference between low line and control.Heritabilities of LGA, LFC and DFI were 0·38, 0·35 and 0·29 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·09 (s.e. 0·02). Genetic correlations for LGA with LFC and DFI were positive, 0·76 (s.e. 0·03) and 0·23 (s.e. 0·07), but the genetic correlation between DFI and LFC was negative, –0·45 (s.e. 0·06). The experiment demonstrated that substantial responses to selection can be achieved in LGA, LFC and DFI. Selection on LGA resulted in larger direct and correlated responses than selection on LFC.
Effects of avoparcin and bovine somatotropin on measures of production and reproduction in dairy cows
Authors: Murphy M. G. , O'Callaghan D. , Rath M. , Austin F. H. , Roche J. F. 
Published: September 2010

AbstractThe objective was to determine the effects of avoparcin, bovine somatotropin (bST) and the additive effects of both avoparcin and bST on milk yield, milk composition, live-weight changes and reproduction parameters in post-partum dairy cows. Forty-eight autumn calving cows were allocated using a split-plot within randomized complete-block design to the following treatments: (i) control (2 ml saline plus 1 kg untreated concentrate per day); (ii) avoparcin (2 ml saline plus 1 kg concentrate containing 100 mg avoparin per day); (Hi) bST (25 mg bST in 2 ml saline plus 1 kg untreated concentrate per day); and (iv) avoparcin plus bST (25 mg bST in 2 ml saline plus 1 kg concentrate containing 100 mg avoparcin per day). All injections were given subcutaneously and treatment continued for 84 days beginning 55 (s.e. 4) days after calving. The cows were offered grass silage ad libitum supplemented with 7·2 kg cereal-based concentrates daily. Milk yield and milk composition were measured thrice and once weekly, respectively. The cows were weighed and body condition score was assessed every 2 weeks.Mean daily milk yield of cows assigned to control was 20·1 (s.e. 1·5) kg, avoparcin, 21·5 (s.e. 1·5) kg, bST, 23·9 (s.e. 1·0) kg and avoparcin plus bST, 25·2 (s.e. 1·2) kg over the 84 days of the trial. bST increased milk yield proportionately by 0·18 compared with all cows not given bST (P < 0·01). Avoparcin did not significantly increase milk yield. There was no effect of any treatment on milk composition, body weight or body condition score. None of the experimental treatments had any effect on calving to first service interval, calving to conception interval, number of services per conception or overall conception rate.These results show that in early lactation, avoparcin alone had no effect on production or reproduction parameters in dairy cows; bST alone increased milk yield but did not affect any other production or reproduction parameter. There was no significant additional increase in milk yield when avoparcin and bST were given in combination, compared with bST alone.
Combining the genetic and clonal responses in a closed dairy cattle nucleus scheme
Authors: de Boer I. J. M. , Meuwissen T. H. E. , van Arendonk J. A. M. 
Published: September 2010

AbstractDesigns testing clones in a closed nucleus, in which 1024 cows are tested each year, were compared for their additive genetic response to selection (genetic response) and their genetic superiority of female genotype(s) selected for commercial cloning (clonal response), using stochastic simulation. Clones were tested at the expense of dam or sire families, matings per dam (sire), or full-sibs per family. The reference design maximized the genetic response corrected for inbreeding in the absence of cloning. The trait considered was overall economic merit for milk production, which was simulated assuming an approximate infinitesimal model with both additive and dominant gene action. Bulls and cows eligible for breeding were selected on their animal model estimated additive genetic effect at either 15 or 27 months of age. Female genotypes eligible for commercial cloning were selected on their estimated total genetic effect at 27 months of age. All (fe)male full-sibs were available for selection. With only additive gene action, testing clones at the expense of sire families, matings per dam or full-sibs per family reduced genetic response, while it increased clonal response and inbreeding. Testing clones at the expense of dam families, however, added to both the genetic and clonal response without increasing inbreeding. When eight clones were tested at the expense of dam families, the genetic response and the final genetic level of commercially available cloned embryos were maximal. Accuracy of clonal selection equalled 0·83. With dominant gene action, however, testing two clones at the expense of dam families maximized the final genetic level of cloned embryos, irrespective of the level of inbreeding depression (accuracy of 0·72). Reliable commercial clone lines can be produced now and in future generations by testing clones at the expense of dam families.
Maximizing genetic response in crossbreds using both purebred and crossbred information
Authors: Wei Ming , van der Werf J. H. J. 
Published: September 2010

AbstractA combined crossbred and purebred selection (CCPS) method, i.e. using crossbred and purebred information, was proposed to achieve genetic response in crossbred animals. Selection index theory was applied to establish a CCPS index. The CCPS was compared with pure-line selection (PLS) and crossbred selection (CS) methods. The genetic correlation between purebred and crossbred performance (rpc) and crossbred heritability (hc2) are crucial factors in the comparison. The CCPS is always better than PLS or CS when a fixed number of purebred progeny is tested. With a fixed total number of purebred and crossbred tested progeny, CCPS is only worse than PLS for very high values of rpc (>0·8). Superiority of CCPS over PLS increases and over CS decreases with decreasing rpc. The larger hc2is, relative to purebred heritability (hc2the more response CS and CCPS will achieve. The robustness of CCPS against inappropriate assumptions on rpcand hc2values was investigated. The expected response is always an overestimate, and the actual response is smaller than the optimal response when rpcis assumed one but the true rpcis smaller. The difference between actual and optimal response increases as rpcdecreases but it is small for large rpcvalues (e.g. <3% for rpc>0·7). The expected response is smaller than the actual response when rpcis large and hc2> hp2Finally, the actual response to CCPS is larger than the optimal response to PLS for positive values for rpc. The main conclusions are: (1) CCPS method is optimal for obtaining genetic response in crossbreds; and (2) CCPS with inappropriate assumptions on rpcand hc2values (e.g. recognizing crossbreds as purebreds) achieves more genetic response than PLS for common values of rpcand crossbred heritability.
The use of sheep as a model to predict the relative intakes of silages by dairy cattle
Authors: Cushnahan A. , Gordon F. J. , Ferris C. P. W. , Chestnutt D. M. B. , Mayne C. S. 
Published: September 2010

AbstractA study was carried out to determine if sheep could be used as a model for predicting the intakes of silages by cattle. Fifty ewes and 45 cows were offered five grass silages unsupplemented in two parallel randomized-block experiments over a 4-week period. Each silage had been made using the same equipment over a range of cutting dates (May, July, August 1991). The silages differed in fermentation characteristics, with lactic acid concentrations varying from 15·3 to 90·7 g/kg dry matter, and ammonia-nitrogen concentrations from 77 to 198 g/kg nitrogen. When expressed on a metabolic live-weight basis, the mean intakes of silages by cows were 2·25 times those of the sheep, with the mean intakes being 35·1 and 79·1 g/kg M0·75 for the sheep and cows respectively. However, there was no significant correlation between recorded intakes during the 4th week of the study by the two species (y (cows) = 0·62× (sheep) + 58·40; r2 = 0·03). It was concluded that sheep were not a useful model system to predict the intakes of a range of grass silages of similar chop length by dairy cows.
Effect of animal size on the response in the performance of beef cattle to an improvement in silage quality
Authors: Steen R. W. J. , McIlmoyle W. A. 
Published: September 2010

ABSTRACTTwo experiments have been carried out to examine the interaction between animal size and the response in animal performance to an increase in the digestibility of grass silage. In experiment 1, grass silages harvested during July and August after regrowth intervals of 43 and 85 days were offered ad libitum both unsupplemented and supplemented with 2 kg of concentrates per head per day to British Friesian steers of (±s.e.) 170±1·9, 300±2·9 and 420±3·6 kg initial live weight. Earlier cutting did not affect silage dry-matter intake or live-weight gain but increased carcass gain by 0·12kg/day (P<0·01).In experiment 2, early-cut grass silage, made from two regrowths of perennial ryegrass, which were harvested during July and August after regrowth intervals of 43 and 48 days, and late-cut silage, made from a single regrowth, which was harvested in August after a regrowth interval of 90 days, were offered ad libitum to 84 Hereford-cross steers of (±s.e.) 170±3·4, 300±4·4 and 420±5|·2kg initial live weight. Earlier cutting increased silage dry-matter intake by 340 g/kg, live-weight gain by 0·23 kg/day and carcass gain by 0·18 kg/day (P<0·001). It i s concluded that increasing the digestibility of grass silage by cutting grass at an earlier stage of growth is likely to produce a substantial increase in the daily carcass gain of beef cattle and that the response to higher digestibility is as great with mature cattle as with young, growing animals.
A note on the effect of limestone supplementation on the performance of cattle given barley-based diets
Authors: Bass Jean M. , Fishwick G. , Parkins J. J. 
Published: September 2010

ABSTRACTGroups of Hereford-cross steers weighing 283 kg were given 0·6 kg dry matter hay per head per day, and bruised barley supplemented with 40 g of a fully soluble liquid product per kg, containing urea, minerals and vitamins,ad libitum. Half the animals received 10 g limestone per kg diet as an additional supplement. Over a 105-day period the food intake of the limestone-supplemented animals was 0·20 higher than that of unsupplemented animals. The resultant daily live-weight gain was 1·22 kg compared with 0·92 kg for the animals receiving the diet containing no additional limestone. Food conversion ratios (kg/kg live-weight gain) were improved by limestone supplementation from 6·84 to 6·19. Limestone inclusion did not appear to influence the low concentrations of starch (ca. 15 g/kg) present in the faecal dry matter but there was a small significant difference in faecal pH.