bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inter-breed relationship of maintenance efficiency to milk yield in cattle
Authors: Taylor C. S. , Thiessen R. B. , Murray J. 
Published: September 2010

ABSTRACTAs part of a multibreed cattle project for studying genetic variation between breeds, four adult females from each of five breeds of cattle were kept for up to 2 years in a non-pregnant, non-lactating state on each of four feeding levels. The breeds, which were Hereford, Aberdeen Angus, Dexter, British Friesian and Jersey, provided a wide range of genetic potential for body size and milk yield. The feeding levels were arranged to make the weight of lipid in the whole body about 0·05, 0·15, 0·25 and 0·35 times body weight. After an animal had been assigned to a fixed daily intake, its body weight and condition score were monitored over a period varying from 6 to 18 months until an equilibrium body weight and body composition had been established.For standard adult body weight, Akg, and for an equilibrium body weight, Wkg, and an associated metabolizable energy intake, f/MJ, the maintenance efficiency of a breed adjusted for breed size was defined as Em = W/fA0·21. The ‘lactability’ of a breed, that is, its genetic potential lactation yield, Ykg, adjusted for breed size, was defined as Y = Y/A. The between-breed regression of Em on Y had a coefficient of -0·043 (s.e. 0·007). There was, thus, a highly significant dairy-beef gradient in the equilibrium maintenance efficiency of these non-pregnant, non-lactating adult females.An expected value for the equilibrium maintenance requirement, of a breed or individual as a function of its lactability was estimated to be:which implies that the maintenance requirement of dairy breeds is about 0·2 times greater than that of beef breeds, a result which was strongly supported by a literature survey, although mean estimates from feeding trials and fasting trials were anomalous.Combining this result for milk yield with published results on growth rate, leads to the hypothesis that the greater the maximum gross efficiency of a breed for meat or milk production, the less efficiently it maintains itself, not because of any difference in fasting metabolism, but because of a reduced efficiency of food utilization for maintenance.
Amino acid requirements of growing pigs. 7. The response of pigs from 25 to 55 kg live weight to dietary ideal protein
Authors: Yen H. T. , Cole D. J. A. , Lewis D. 
Published: September 2010

ABSTRACTOne hundred and twenty pigs were used in a 3 × 8 factorial design. The factors were sex, 40 trios of littermate boars, castrated males and gilts, and dietary lysine, eight concentrations from 7×5 to 14×5 g/kg diet with 1 g/kg diet intervals of lysine with corresponding crude protein (CP) concentrations from 114 to 226 g/kg diet. Increases in dietary lysine were associated with concomitant increases in the other essential amino acids so as to provide an ideal protein. All diets had similar digestible energy values (13·65 MJ/kg). Pigs were fed once daily on a restricted scale from 25 to 55 kg live weight. For growth and carcass characteristics there was a range of linear response followed by a plateau. The inflexion points of dietary lysine for growth characteristics were at 11·1, 10·2 and 10·9 g/kg diet (171, 157 and 168 g CP per kg diet) together with daily intakes of 18·0, 16·7 and 17·6 g (daily intake of 277, 257 and 271 g CP) for boars, castrated males and gilts respectively. The equivalent points for carcass characteristics were 10·4, 9·7 and 10·1 g/kg (160, 149 and 156 g CP per kg diet) with daily intakes of 16·9, 15·9 and 16·4 g lysine (daily intakes of 260, 245 and 252 g CP). Blood urea data gave good support for these observations.
The energy value to sheep of saturated and unsaturated fat fed singly or in combination
Authors: Wainman F. W. , Dewey P. J. S. 
Published: September 2010

ABSTRACTFour diets containing either 0 or 50 g fat per kg were prepared from a basal mix of barley, sugar-beet pulp, soya-bean meal and molasses. The fats used were tallow (saturated), soya-acid oil (unsaturated), or a 45:5 mixture of both fats. The diets were given with chopped dried grass to adult wether sheep in the ratio 4:1 of diet to dried grass. Measurements of heat production of the sheep were made in closed-circuit respiration chambers and from the data the efficiencies of utilization of energy for maintenance (km) and production (kf) were calculated for each diet, together with the metabolizable energy (ME) values for the fats.Values for bothkmandkfwere not significantly different between diets, the means were 0·81 and 0·61 respectively. The ME values (MJ/kg DM) of the fats were for tallow 36·2, for soya-acid oil 36·6 and for the tallow/soya mixture 31·6; these values were not significantly different.No evidence of any synergistic effect caused by the addition of an unsaturated fat to a saturated fat was seen in this experiment.
Milk production in early lactation dairy cows given grass silagead libitum: Influence of concentrate energy source, crude protein content and level of concentrate allowance
Authors: Sloan B. K. , Rowlinson P. , Armstrong D. G. 
Published: September 2010

ABSTRACTThere is increasing interest in how the raw material make-up of concentrates can influence the milk performance of dairy cows. Thus, over two consecutive winters, 54 dairy cows were used to investigate the effects on dry matter (DM) intake, milk yield and its composition of feeding concentrates of diverse energy source (LNDF — 131 g neutral-detergent fibre per kg DM, 492 g starch plus sugars per kg DM; HNDF — 244 g neutral-detergent fibre per kg DM, 293 g starch plus sugar per kg DM) at two formulated crude protein (CP) levels (157v.187 g/kg DM) and three levels of concentrate allowance (9, 11, 13 kg DM). The concentrates were formulated to be of equivalent metabolizable energy concentration (MJ/kg DM) and were offered with silagead libitumfor a 10-week period (weeks 4 to 13 of lactation).Silage intakes were variable but not significantly influenced by concentrate energy source or formulated CP level, except in the 1st year where animals consuming the high CP concentrate ate more silage. Silage DM intake decreased as concentrate allowance was increased with the substitution rate (kg silage DM per kg concentrate DM) increasing as concentrate allowance was increased.Increasing the concentrate allowance effected the expected increases in milk yield. Concentrate energy source did not influence milk yield but the higher CP levels effected a 2-kg increase in milk yield. Feeding of LNDF concentrates depressed milk fat concentration and its yield, the depression being accentuated with each increase in concentrate allowance. The depression in milk fat concentration was negatively correlated with the forage: concentrate ratio of the diet consumed. Furthermore, dietary NDF proportion was shown to account for greater than half of the variation in milk fat concentration. In contrast to the observations made for milk fat, feeding the LNDF concentrates effected an increase in milk protein concentration but only at the lower CP level of the concentrate.
Evaluation of British Friesian, Canadian Holstein and beef breed × British Friesian steers slaughtered over a commercial range of fatness from 16-month and 24-month beef production systems 2. Carcass characteristics, and rate and efficiency of lean gain
Authors: Kempster A. J. , Cook G. L. , Southgate J. R. 
Published: September 2010

ABSTRACTCarcass characteristics, and the rate and efficiency of lean gain of purebred British Friesian and Canadian Holstein steers and of crossbred steers out of British Friesian dams by Charolais, Hereford, Limousin, Lincoln Red, Simmental, South Devon and Sussex sires were examined in two beef production systems. One was similar to the commercial 18-month grass/cereal system (16-month) and the other to a commercial 2-year system (24-month). The cattle were serially slaughtered at three pre-determined fatness levels, estimated by the Scanogram ultrasonic machine. The trial extended over 4 years and involved a total of 650 cattle, 398 of which had their left sides separated into tissues. Breeds were compared at equal carcass subcutaneous fat proportion determined by visual carcass assessment (SFe). Data for the two production systems were analysed separately.Sire breed differences were not detected in the regression on SFe for most characteristics (P > 0·05). Sire breeds differed in killing out and visual conformation score in both production systems (P < 0·001): Charolais and Limousin crosses had the highest values and purebred Canadian Holsteins the lowest. The overall range between sire breeds was 30 g carcass weight per kg live weight and five points on a 15-point conformation scale.Breeds with the higher conformation scores generally had higher carcass lean proportions and higher lean: bone ratios. Canadian Holsteins had a 20 g/kg lower carcass lean proportion than the British Friesians (P < 0·05).Breed crosses with larger adult body size tended to have higher lean tissue growth rates: the difference between mean values for Charolais crosses and Hereford crosses was 49 g/day (16-month) and 38 g/day (24-month). The lean tissue growth rates of the British Friesians and especially the Canadian Holsteins were low in relation to their adult body size.Limousin and Charolais crosses had the highest efficiency of lean gain (g lean per kg digestible organic matter intake). These and the other crosses were significantly more efficient than the purebred Canadian Holsteins (P < 0·05). The overall range between breeds was 20 g/kg.
The effect of sward height and active immunization against androstenedione on reproductive performance of ewes of two Welsh breeds in different body conditions
Authors: Gunn R. G. , Rhind S. M. , Maxwell T. J. , Sim D. A. , Jones J. R. , James M. E. 
Published: September 2010

ABSTRACTIn a 2 × 2 × 2 × 2 factorial experiment, the effects on reproductive performance of active immunization against androstenedione and of two sward heights in two periods, August to October (period 1) and October to November (period 2), were investigated in 144 Beulah Speckled-face and 146 Brecknock Cheviot ewes. Sward heights of either 5 to 6 cm (2200 kg dry matter (DM) per ha) (high) or 2 to 3 cm (650 kg DM per ha) (low) were achieved by adjustment of stocking rate during period 1. Two groups of ewes were balanced for body condition score across breed and sward height and the ewes of one group were actively immunized against androstenedione by injection with Fecundin® at 8 and 5 weeks before mating at the second synchronized oestrus after progestagen pessary withdrawal. Ewes were reallocated to the high (at 15 ewes per ha) and low (at 20 ewes per ha) swards at the start of period 2 by breed and immunization treatment, balanced for live weight, body condition score and sward height in period 1. After mating in mid November, all ewes were run at 19 ewes per ha on the residual pasture of the high sward until slaughtered either at return to service or at 4 weeks after first mating when corpora lutea and embryos were counted.There were no effects or interactions due to sward height in period 1 on the reproductive responses to sward height in period 2. Ovulation and potential lambing rates were greater in the Beulah breed than in the Cheviot, and on the high sward than on the low in period 2. Ovulation rates were higher in immunized ewes than in control ewes but the effects of immunization and sward height on potential lambing rate were not independent. Potential lambing rates were higher in immunized ewes than in control ewes at the low sward height but not at the high sward height.Adjustment of stocking rate during period 1 served to increase the range in ewe body condition at the start of period 2 in mid October. Reproductive response to body condition at this time differed between the breeds, the relationship being strongly positive in the more prolific Beulah control ewes but less so in the less prolific Cheviot control ewes. The response to immunization in both breeds was relatively greater at lower levels of body condition, thereby reducing the effect of body condition in immunized ewes.The use of Fecundin® is therefore unlikely to produce much advantage when pre-mating nutrition or body condition are high but there may be some advantage in using it when nutritional resources are limited in the autumn, particularly in ewes in poorer body condition.
Utilization ofdl- andl-tryptophan in young pigs
Authors: Schutte J. B. , van Weerden E. J. , Koch F. 
Published: September 2010

ABSTRACTTwo trials involving young pigs (total numbers 288 and 400, respectively) were performed to compare the biological activity of Dl- and L-tryptophan under restricted (trial 1) andad libitum(trial 2) feeding conditions. In trial 1, three additions of Dl-tryptophan (0·3, 0·6 and 0·9 g/kg) and two additions of L-tryptophan (0·3 and 0·6 g/kg) to a basal diet containing 0·9 g natural tryptophan per kg were tested. In trial 2, the treatments were additions of 0·4, 0·8 and 1·2 g Dl- or L-tryptophan per kg to a basal diet having 1·3 g natural tryptophan per kg. Both trials were of 6 weeks duration. In trial 1, almost equal performance was achieved with both tryptophan sources at a dietary level of 0·3 g/kg, whereas at a level of 0·6 g/kg, Dl-tryptophan produced slightly better performance in weight gain, food intake and food conversion efficiency than did L-tryptophan. In trial 2, the supplemental level of 0·4 g L-tryptophan per kg produced weight gain and food intake results which were significantly superior to those of Dl-tryptophan. However, at supplemental levels of 0·8 and 1·2 g/kg, diets with Dl-tryptophan produced somewhat better performance than did L-tryptophan. Based on the results of trial 2, it was estimated that the pig's need for total tryptophan over the weight range of 10 to 35 kg is at least 2·3 g/kg in a diet having 10·3 MJ net energy per kg.
Some factors affecting the estimation of genetic parameters for cattle dystocia under a threshold model
Authors: Manfredi E. J. , Cristobal M. San , Foulley J. L. 
Published: September 2010

AbstractGenetic parameters for dystocia in the Main-Anjou breed were estimated. Data consisted of 28 178 birth records collected between 1978 and 1989 in 995 herds, with 161, 71 and 12 415 sires, maternal grandsires and dams, respectively, represented. Original scores (1 through 5) were collapsed in order to set two dystocia definitions: dystocia 1 (scores 1+2v.3+4+5) and dystocia 2 (scores 1v.2+3+4+5). Four models were proposed for genetic parameter estimation: (1) fixed effects plus sire effects; (2) model 1 plus maternal grandsire effect; (3) model 2 plus dam within maternal grandsire effects; (4) same as model 3 but a random effect ‘herds’ replaced a fixed effect ‘regions’. Two methods of fitting models were applied: marginal maximum likelihood and the ‘tilde-hat’ approach. Estimates of genetic parameters by the two methods were similar. Models ignoring maternal effects overestimated the heritability of direct effects especially in the case of dystocia 2. Dystocia definition was responsible for the greatest difference among estimated genetic parameters. Possible reasons for this are discussed. When analysing large data sets, it is recommended judiciously to collapse dystocia categories and to apply approximate statistical procedures to complete models including maternal effects.
The digestion and utilization of amino acids of heat-treated fish meal by growing/finishing pigs
Authors: Wiseman J. , Jagger S. , Cole D. J. A. , Haresign W. 
Published: September 2010

AbstractA batch offish meal was (a) untreated, (b) heated to 130°C and (c) heated to 160°C under controlled conditions.In trial 1, these materials were incorporated into a diet based on barley meal (278·7 g/kg), wheat starch (412·5 g/kg), maize meal (245·3 g/kg) and tallow (33·5 g/kg) at a rate of inclusion of 100 g/kg. Diets contained a vitamin/mineral pre-mix together with the inert marker titanium dioxide and were given to four pigs fitted with simple T-piece Heal cannulas over four time periods each of which lasted for 6 days and which allowed the determination of faecal and Heal apparent digestibilities of nitrogen and amino acids. The results indicated that over-heating fish meal results in a reduction in both Heal and faecal apparent digestibility although, as there was no effect of treatment on the quantity of nitrogen absorbed from the large intestine, the two measurements were directly related. Heal and faecal apparent digestibilities for individual amino acids were not the same as data for nitrogen and, accordingly, the latter cannot be used to predict the two former.In trial 2, the three fish meal samples were included in diets formulated on the basis of total, faecal and Heal apparent digestible amino acids. The nine diets were given to pigs over the live-weight range 27·5 to 52·5 kg. Giving diets formulated on the basis of both faecal and Heal apparent digestible amino acids resulted in improved performance compared with giving diets based on total amino acids when the diets containing fish meal heated to 160°C, but performance achieved with diets containing untreated fish meal was still higher.Heal apparent digestible amino acids from heat-treated fish meal are not completely available to the pig, and it is suggested that care needs to be taken in equating digestibility with subsequent availability. There appears to be no advantage of using Heal rather than faecal, apparent digestible amino acid values in texms of accuracy of diet formulation.
Production responses of lambs immunized against somatostatin
Authors: Zainur A. S. , Hoskinson R. M. , Kellaway R. C. 
Published: September 2010

AbstractThe production responses of crossbred lambs [Poll Dorset (♂ × (Border Leicester ♂ × Merino ♀)] immunized against somatostatin (sornatotropin release inhibiting factor; SRIF) and whose mothers were also given anti-somatostatin vaccination was investigated in this study. There were no significant differences between immunized and control lambs in term of live-weight gain, food intake, food conversion efficiency, digestibility, eating pattern, wool growth and carcass composition. The concentration of growth hormone in plasma of immune lambs was not significantly elevated, even though the lambs had a generally increasing anti-SRIF antibody titre during the experiment. The findings suggest that although the lambs were successfully immunized against SRIF, homeorhetic mechanisms maintained growth hormone and productivity traits within normal levels.
Effects of management options on creep feeding by piglets
Authors: Appleby M. C. , Pajor E. A. , Fraser D. 
Published: September 2010

AbstractEffects of creep food presentation on feeding behaviour and intake were studied with eight litters of eight to 10 Yorkshire × Landrace piglets in the 3rd and 4th weeks after birth, before weaning at 4 weeks of age. In each week, four treatments were applied, each for 24 h: a single two-space feeder unchanged from the previous day; a clean feeder with fresh food supplied at 09.00 h; a clean feeder with fresh food supplied at three times during the day; and three feeders (six feeding spaces) providing increased access to food throughout the day. There were no significant differences between the first three treatments in time spent at the feeder (recorded by video over 24 h) or food intake of piglets. However, the fourth treatment increased average intake in week 3 to 2·1 times the average of the other treatments, and in week four to 1·4 times. In week 3, most piglets spent more time at the feeder when access was increased, while in week 4 the effect was restricted to piglets which ate very little. This suggested that imitative learning was important in the initiation of feeding. Analysis of both litter means and within-Utter variation showed that piglets which ate more solid food before weaning gained more weight in the 2 weeks after weaning. However, this correlation was confounded by correlations of both measures with birth weight and other variables. Causal links between creep feeding and post-weaning weight gain remain to be demonstrated.
Prediction of the yields of milk constituents in dairy cows offered silagead libitumand concentrates at a flat rate
Authors: Rook A. J. , Sutton J. D. , France J. 
Published: September 2010

AbstractIndividually recorded milk yields, yields and concentrations of milk components, food intakes and live weights of multiparous dairy cows given silagead libitumand concentrates at a flat rate in weeks 4 to 13 of lactation and data for silage and concentrate composition from experiments conducted at four sites, were used to obtain simple correlations and multiple linear regressions of yields and concentrations of milk constituents on other variables.Simple correlations between yields and concentrations and other variables were low. Yield terms were most highly correlated with intake terms. Milk fat concentration was most highly correlated with silage fibre concentration. Milk protein concentration was most highly correlated with digestible energy intake. The best multiple regression models including time effects accounted proportionately for 0·35 of the variation in fat yield, 0·51 in protein yield, 0·55 in lactose yield, 0·39 in total milk yield, 0·19 in fat concentration, 043 in protein concentration and 0·19 in lactose concentration. Most of these models included terms for silage intake and cow live weight which are not generally available on farms. More practical models including fewer independent variates were therefore produced. These models accounted proportionately for 0·33 of the variation in fat yield, 048 in protein yield, 0·50 in lactose yield, 0·32 in total milk yield, 0·19 in fat concentration, 0·40 in protein concentration and 0·17 in lactose concentration.
Heterogeneity of variance and dairy cattle breeding
Authors: Visscher P. M. , Hill W. G. 
Published: September 2010

AbstractThe effects of heterogeneity among herds in phenotypic variance (σ2p) and in heritability (h2) on the accuracy of evaluation of dairy sires and cows are discussed with reference to estimates from field data. It is argued that heterogeneity of σ2P can be accounted for by using a (Bayesian) regression procedure. While the same procedure could be used to correct for heterogeneity of h2, in most practical situations the sampling errors of the h2 estimates for individual herds are likely to be so large that regressed estimates of h2 will differ little from each other, so constant values can be assumed.
Intake, digestion, gastro-intestinal transit time and nitrogen balance in working oxen: studies in Costa Rica and Nepal
Authors: Pearson R. A. , Lawrence P. R. 
Published: September 2010

AbstractExperiments were carried out in Nepal and Costa Rica to compare voluntary dry-matter intake (DMI) by oxen of diets based on poor quality hay (Costa Rica) and rice straw (Nepal) supplemented with different levels of concentrate foods when the animals were working and not working. Values for the apparent digestibility of the diets, rates of passage of solid and liquid phases ofdigesta and nitrogen balance are also reported.Amounts of work calculated to raise daily energy expenditure to 1·3 to 1·6 × maintenance were associated with the following effects. (1) A depression of proportionately 0·11 and 0·14 in the DMI of oxen given a diet based on rice straw plus 18 and 27 g/kg live weight of concentrate respectively during work. No depression of DMI was seen with the hay diets which had slightly higher metabolizable energy but less nitrogen than the rice straw diets. (2) An increase in intake in the weeks following work on both the hay and rice straw diets. (3) Variable effects on apparent digestibility of food probably related more to the changes in DMI. (4) A tendency for gastro-intestinal mean retention time to be increased in working weeks particularly on the more fibrous diets.