bluuebunny/crossref_metadata_2025_split huggingface dataset:
A notes on nutrient digestibility and nitrogen retention in ewes fed whole grains of triticale, wheat and maize
Authors: Felix A. , Hill R. A. , Winchester W. 
Published: September 2010

ABSTRACTTwo digestion trials were conducted using sheep fed whole grains of triticale, wheat or maize on an equal amount or an isonitrogenous basis. Nine ewes were used in a 10-day collection period for each trial. Both trials consisted of three treatment groups of three animals each. Each ewe received daily either 1200 g of a diet containing 740 g (per kg diet) triticale, wheat or maize (trial 1) or 900 g of a diet containing 650, 650 and 600 g (per kg diet), respectively, of the above grains. Digestibilities of various nutrients, dry matter and organic matter were generally similar among treatments. However, apparent digestibility of crude fibre was significantly higher for ewes fed triticale than for those fed maize or wheat diets.
Feeding of dairy cows: a survey of the concentrate usage of high yielding cows during the winter
Authors: Rickaby C. D. 
Published: September 2010

SUMMARY(1) A survey was conducted to determine the concentrate usage during the winter (1962–63) of each of 125 high-yielding dairy cows. The bulky foods consumed by each cow were also recorded.(2) On average the cows were given 3.64 lb. concentrates per gallon of milk produced, and their intake of starch equivalent in excess of that needed for maintenance was 2.54 lb. per gallon. The margin per month (milk sales less cost of concentrates) was £14 13s Od.(3) The implications of the results of the survey are discussed in relation to the feeding of dairy cows.
The interpretation of genotypic ratios in domestic animal populations
Authors: Robertson Alan 
Published: September 2010

SUMMARYIf, from a population, samples of individuals are drawn with a small number of parents, it is shown that there will be on average an apparent excess of heterozygotes above the number calculated from the gene frequency in each sample. The apparent proportional excess is where M and F are the number of male and female parents. This is independent of the number of alleles at the locus concerned. The use of the usual significance tests will also be affected. If analyses are done within herds of domestic livestock, particularly cattle, the number of sires in use at any time is likely to lead to a bias of a size which is of biological importance. The conditions under which genotypic ratios can usefully be examined are discussed.
The use of station and field tests for the improvement of milking performance in dairy cattle. I. Variation in milk yield and butterfat in test station records
Authors: Hinks C. J. M. 
Published: September 2010

A study of variation in milk yield and butterfat has been undertaken, using the test station records of almost 5 000 first-calf cows of three dairy breeds.The general object of the investigation was to provide a background for a more comprehensive examination of the important productive characteristics of dairy cattle, and of the use of different sire-testing procedures for their improvement; the specific object was to consider the possible causes of large sire components and heritability estimates that have been observed in all analyses of test station production data, and the reasons why the station and field tests of a bull do not always correspond.Large heritability estimates for milk yield, fat yield and fat percentage were obtained in the Danish Red and Black Pied breeds, but the corresponding estimates in the Jerseys (0·31, 0·48 and 0·58 respectively) were similar in size to the values normally obtained for these traits in field data.The pre-selection of heifer recruits to the stations, and breed differences in the intensity of selection applied to the productive characteristics, were considered and dismissed as causes of abnormal sire components, in the light of results obtained from field data which indicated that the heritability of milk yield in the Jerseys was not lower than in the other two breeds (0·26, 0·37 and 0·36 in Danish Reds, Black Pied and Jersey).It was suggested that differences between records made in test stations and records made in farmers' herds may be caused by differences in milking efficiency, by differences in culling practices in the two environments, and by the effects of age, season at calving and contemporaneity. Other investigations have established that these factors may have a large influence on the variance components of the production traits, and all of them would repay further investigation.
Time taken to mature in relation to mature weight for sexes, strains and species of domesticated mammals and birds
Authors: Taylor C. S. 
Published: September 2010

The relationship between mature weights of domestic species and the times they take to mature in live weight is extended to breeds and strains within a species and to sex differences within a breed or strain. Results based on the Gompertz growth curve are found to be essentially the same as those based on Brody's growth curve. Both confirm the relationship of proportionality between the time a species takes to mature in live weight and its mature weight raised to the power 0·27 or some power close to this. The overall weighted average coefficient was 0·273 ± 0·029 for Brody's (1945) growth curve data and 0·276 ± 0·030 for the Gompertz growth curve data of Laird (1966). The weighted average coefficients of 0·358 ± 0·098 for strains within a species and 0·343 ± 0·049 for sexes within a strain, although not significantly greater than 0·27, suggest that a coefficient of ⅓ might be a better value to adopt when the relationship is confined within species.Birds as a class matured significantly more rapidly than expected from their mature weight and mammals significantly more slowly. Body temperature could account for this class difference in maturing time but not for deviations of individual species or strains. Relative to their mature weight, some species appeared to take much less time to mature than others, with possibly a 2- to 3-fold genetic difference between extremes of the range.The main use of the relationship obtained lies in providing a ‘metabolic’ age scale on which animals or species can be examined for differences in immature physiological characteristics such as maturing time, body composition or efficiency of food utilization independently of differences in adult size.
Studies on the nutrition of ruminants. 3. The substitution of soya bean meal by urea in diets containing ground roughage and cereal
Authors: Swan H. , Lamming G. E. 
Published: September 2010

Thirty-two yearling Friesian steers were used in a 2 × 2 factorial experiment. The treatment variables were source of supplementary nitrogen and physical form of the diet. The diets contained 30% ground barley straw, ground maize, a nitrogen supplement, and minerals and vitamins. Urea was compared with soya bean meal as the nitrogen supplement and both diets were given as cubes or meal. There was no significant difference between treatments in daily live-weight gain, feed intake or commercial carcass acceptability.Digestibility trials with wethers showed the apparent digestibility of nitrogen and dry matter of the diet containing urea to be significantly lower than that of the diet containing soya bean meal (nitrogen 72·8 ν. 76·3, P < 0·001; dry matter 70·2 ν. 75·3, P < 0·01). The results are discussed in relation to the digestibility of the diets used, the source of supplementary nitrogen and the physical form of the diet.
The use of station and field tests for the improvement of milking performance in dairy cattle. III. Breed differences in the yield of milk and butterfat from the fore and rear quarters of the udder
Authors: Hinks C. J. M. 
Published: September 2010

The analysis was concerned with selective advantage as a possible cause of differences between breeds and individual animals in the relative proportions of milk obtained from the fore and rear quarters of the udder.Danish Jersey cattle were found to yield a significantly higher proportion of milk from the fore quarters than Danish Red and Danish Black Pied cattle (47% ν. 45% and 44% respectively).Very strong genetic relationships between the proportion of milk obtained from the fore quarters and lactation yields of milk and butterfat (rg = 0·92, 0·85) in the Jerseys, and correspondingly weak genetic relationships in the other two breeds, suggest that breed differences have arisen as a result of selection for productive performance operative upon different genetic relationships between production and the process controlling the partition of milk in the udder. It is suggested that differences between the breeds are likely to increase in the future.
Food intake and live-weight gain comparisons of Bos indicus and Bos taurus steers on a high plane of nutrition
Authors: Rogerson A. , Ledger H. P. , Freeman G. H. 
Published: September 2010

1. The voluntary dry-matter and water intakes of indigenous and exotic cattle on high plane rations have been compared under similar conditions of management.2. At similar live weights, exotic cattle have a much higher feed intake
relative to maintenance than indigenous cattle.3. Water intake was closely related to dry-matter intake, irrespective of live weight, and varied only very slightly between the two types of cattle.4. Exotic cattle were more than twice as efficient as indigenous cattle in converting feed into live-weight gain. It is suggested that this is largely a reflection of the increased feed intake, relative to maintenance requirements.5. Stage of maturity, degree of fatness and their relation to conversion
efficiency are discussed.
Factors affecting the shape of the lactation curve in cattle
Authors: Wood P. D. P. 
Published: September 2010

SUMMARYThe lactation curve in cattle has been explained by the expression
yn = Anbe-cn
where yn is the average daily yield in the nth week, and A, b, and c are constants. In general, in a sample of 859 Friesian lactations recorded during 1964–65 daily yield was depressed during the winter months (18·8% in January) and stimulated during the spring (14·7% in May) to an extent which was independent of the stage of lactation. Winter calvers on the other hand tended to produce more in total lactation than spring calvers (14·5% for animals calving in November as opposed to those calving in April).Using a suitable technique it is possible to predict month by month output from a cow, or herd, accurately enough to furnish a basis for forward planning.
The association of food conversion ratio, age at slaughter and carcass quality in pigs fed ad libitum
Authors: Owen J. B. , Morton J. R. 
Published: September 2010

SUMMARYData from a boar progeny testing scheme based on ad libitum feeding were analysed to test the hypothesis that the resultant correlations of food conversion ratio with related factors would differ from those found under conditions of restricted feeding.The results support the hypothesis, showing that the primarily genetic correlations derived from boar effects for growth and conversion ratio, are lower than those reported elsewhere for restricted feeding. It was also shown that these primarily genetic correlations could vary between breeds, the leanness associated with rapid growth in Wessex not being found in Large White, and that the correlations due to residual effects containing a greater environmental component varied widely from test to test.It is concluded that the parameters used in the design of a genetic improvement scheme should be derived specifically for each breed and feeding system. However, if the marked variability in phenotypic correlations noted here is generally applicable, this could present a difficult problem in the design of pig improvement programmes with multiple objectives.
Effect of unwilted and wilted silages and hay, supplemented with different amounts of concentrate, on live-weight gain of calves
Authors: Bartholomew P. W. , McLauchlan W. , Chestnutt D. M. B. 
Published: September 2010

ABSTRACTThree experiments were carried out to investigate the effect of different forage types on the performance of male British Friesian calves up to 6 months of age. Unwilted and wilted silages were compared in all experiments, and in experiment 1 hay was also compared with the two silages. All the forages were compared at different levels of concentrate supplementation ranging, in different experiments, from none to ad libitum.Calves fed wilted silage consumed 490, 90 and 200g/kg more forage dry matter respectively than those fed unwilted silage in the three experiments but this extra intake was generally not reflected in an increased rate of gain. Hay which was of lower digestibility than silage gave significantly lower live-weight gain. Quantities of silage consumed at an early age were small, with a mean daily intake over the first five weeks of 0·13 kg dry matter. Concentrate reduced silage dry-matter intake by 0·49 kg/kg concentrate dry matter consumed. Estimated mean concentrate intake required to achieve a daily gain of 0·75 kg in 1- to 6-month-old calves with silage offered ad libitum was 0·83 kg dry matter.
Reproduction in the gilt 4. The effect of rearing gilts with contemporary castrated males or intact males on the attainment of puberty
Authors: Cole D. J. A. , Dyck G. W. , Nathan S. 
Published: September 2010

ABSTRACTSixty-six Landrace × (Landrace × Large White) gilts were allocated at 70 days of age to one of three rearing treatments of housing with gilts, contemporary castrated males or contemporary intact males. Half the experiment was completed in winter and half in spring. At 159 days of age all gilts were subjected to a change of pen and, from 160 days of age, daily exposure to mature vasectomized boars. The rearing treatments had a small but significant effect on the time interval from boar exposure to puberty, with gilts housed with gilts averaging 8·9 days to puberty compared with 7·1 days and 7·4 days for gilts housed with castrates and boars, respectively (p < 0·05). In addition, there was a seasonal effect on the time interval to puberty. Gilts receiving mature boar exposure during the winter months had a longer interval to puberty than gilts exposed to boars during the spring (8·8 days v. 6·9 days; P < 0·01). These results indicated no habituation effects of gilts housed with contemporary males but, rather, the possibility of a slightly earlier induction of puberty.
The effects of birth weight and level of feeding in early life on growth and development of muscle and adipose tissue in the young pig
Authors: Campbell R. G. , Dunkin A. C. 
Published: September 2010

ABSTRACTForty-two piglets were used to study the effects of heavy and light birth weight, and of four levels of feeding, ranging from 37 to 91 g dry matter per kg M0 75 per day, on growth between 5 days of age and 6·5kg live weight, and on body composition, and the cellularity of muscle and subcutaneous adipose tissue, at the latter weight. The effects of birth weight and level of feeding to 6·5 kg on performance between 6·5 and 11 -5 kg, and on body composition at 11·5 kg, were also investigated.Light birth weight piglets grew more slowly to 6·5 kg than those of heavy birth weight (P< 0·05). However, birth weight had no effect on food conversion efficiency or on body composition.Each increment in feeding level resulted in increases in growth rate (P< 0·01), body fat content (P< 0·01) and average fat-cell diameter (P< 0·01) at 6·5 kg, but in decreases in body protein and water (P< 0·01).The weight of the m. semitendinosus at 6·5 kg was unaffected by either birth weight or level of feeding. However, the deoxyribonucleic acid content of the muscle at both 6·5 and 11·5 kg was less in light birth weight piglets fed at the lowest level prior to 6·5 kg (P< 0·05). These piglets also exhibited poorer growth performance subsequent to 6·5 kg than their heavier birth weight counterparts.Nevertheless, piglets of both light and heavy birth weight, fed at the lowest level to 6·5 kg, grew faster and more effficiently between 6·5 and 11·5kg (P< 0·05), and were leaner at 11·5kg than those previously fed at the highest level (P< 0·01). Average fat-cell diameter at 11·5kg was also less in pigs fed at the lowest level prior to 6·5kg (P< 0·01). Total deoxyribonucleic acid in subcutaneous adipose tissue at 11·5kg was unaffected by either birth weight or level of feeding prior to 6·5 kg.
A note on growth rates and maturation rates in beef bulls
Authors: Webster A. J. F. , Ahmed A. A. M. , Frappell J. P. 
Published: September 2010

ABSTRACTValues for weight and age of beef bulls at stud have been used to describe growth beyond the point of inflexion of the growth curve. Using the concept of ‘metabolic age’ it was shown that the maturation rate in Aberdeen Angus and Friesian bulls was close to a reported interspecies mean value. Hereford and Charolais bulls both matured relatively rapidly. Variation between individuals within a breed was consistent with the hypothesis that it is possible to select for rapid growth rate without necessarily selecting for an increase in mature size.
A note on a computer program for independent culling
Authors: Saxton A. M. 
Published: September 2010

ABSTRACTCalculating optimal truncation values for independent culling selection procedures has been difficult. Previously published charts took much of the tedium out of the calculations but the charts are difficult to read with accuracy and are not available for all possible parameter values. Therefore a computer program was written to calculate optimal truncation values for two-trait independent culling, with the option of restricting the genetic change of one or both traits. The program is described and an example of its use is given.
Calving dates and subsequent intercalving intervals in New Zealand beef herds
Authors: Morris C. A. 
Published: September 2010

ABSTRACTThe calving dates of spring-calving cows in New Zealand Angus and Hereford herds, taken from 350 and 240 herd-years respectively, and the intercalving intervals (CI) of cows in 95 Angus and 73 Hereford herds have been summarized. The relationships of each CI with the calving date which initiated it were also analysed. Results for each breed were analysed taking account of district, herd, year and cow age (in years), a total of 35 890 Angus and 22 397 Hereford records being used. The first-calving date (FCD) was identified for each herd-year, and 0·82 of Angus and 0·75 of Hereford cows were recorded as calving within 60 days of the FCD. On a herd basis, proportionately only 0·27 of Angus and 0·15 of Hereford herds had calving spreads of 80 days or less (defined as the time from the FCD to the last calving date). With barren years ignored, the CIs of cows averaged 370 days (Angus) and 368 days (Hereford). Two-year-old cows had on average a CI of 12 (Angus) or 7 days (Hereford) longer in 1974-75 than older cows, and the differences were both 12 days in 1975-76. Regression analyses showed that, on average, the later the calving date within a herd-year and age group, the shorter the subsequent CI. For cows calving early in the first year, the CI increased by 7 days for Angus and 5·4 days for Herefords for each 10 days before the mean calving date for the breed. There were significant effects of district and cow age on the regression estimates. The overall regressions were not consistent with those derived from British beef industry data.
Effect of daylength at birth and lunar phase on the occurrence of first oestrus in beef heifers
Authors: Greer R. C. 
Published: September 2010

ABSTRACTData records from 556 beef heifers which included age at first oestrus (AFE) were used to test the null hypotheses: 1) daylength at birth is not a determinant of AFE in beef females; and 2) there is not an association between the day on which first oestrus occurred and the lunar phase.The effect of daylength at birth was measured by forming a variable, X1 where X1 = sine (X1′ 360/365·25)°, and including it among the set of variables in a multiple linear regression equation with AFE as the dependent variable. The resultant estimated coefficient on X1 was -3·617 with a standard error of 21·32, and led to the conclusion that daylength at birth was not a factor which affected AFE in this group of beef heifers.The lunar phase hypothesis was tested by forming the frequency distribution of the 556 observations of first oestrus over the 30-day lunar cycie. The chi-square test was applied with the theoretical (hypothesized) distribution being the uniform distribution. The value of the test statistic was such that the null hypothesis would not be rejected even with an a value approaching 0·50. Additionally, coefficients of autocorrelation calculated for lag phases of 7, 14 and 21 days were quite small. Thus it was concluded that the occurrence of first oestrus was uniformly distributed over the lunar cycle.
Responses in lamb performance from selection on sire 100-day weight
Authors: Cameron N. D. , Smith C. 
Published: September 2010

ABSTRACTForty-one Texel and Texel-Oxford sires were selected over 5 years (1978-82) on high and low adjusted 100-day weight from 174 ram lambs artificially reared from birth and performance tested. The correlated responses to selection were measured in 1103 crossbred progeny, out of an experimental group of crossbred ewes, the progeny being naturally reared in field conditions. Hierarchical analysis of variance was performed, fitting the usual fixed effects and interactions. Co-heritabilities (rAh2h2; rA is the genetic correlation between traits with heritabilities h12 and h22) were estimated from offspring-parent regression and from the realized responses to selection. The selection differentials achieved (1·70 standard deviations in 100-day weight between high- and low-weight sires) were lower than expected, due to mating difficulties, mortality and other requirements for the stock. The co-heritabilities for growth traits were generally positive but small (mean 0·08; s.e. 0·08). Though not statistically significant, lambs slaughtered at a fixed weight from the high-weight rams were slaughtered earlier with lighter and leaner carcasses, as expected. Similarly, lambs slaughtered according to fat cover from high-weight rams were slaughtered later with heavier slaughter and carcass weights. Generally, the co-heritabilities for carcass traits were not significantly different from zero for either slaughter group. On the basis of these results, selection on ram 100-day weight with artificial rearing may not offer any advantage over natural rearing in the improvement of lamb growth and carcass traits.
Bovine growth hormone in lambs: effects on carcass composition and tissue distribution in crossbred females
Authors: Butler-Hogg B. W. , Johnsson I. D. 
Published: September 2010

ABSTRACTThirty-two Dorset Down × Finn Dorset female lambs were reared from 8 to 20 weeks on an ad libitum concentrate diet. They comprised four groups of eight lambs, one on each of the following treatments: (1) control, no injections; (2) daily subcutaneous injection of 0-1 mg bovine pituitary growth hormone (bGH) per kg live weight; (3) daily subcutaneous injection of 1 mg bromocriptine mesilate (Br); (4) daily injections of both bGH and Br at the same rates as treatments (2) and (3).There were no important differences in carcass composition or tissue distribution between the +bGH and +bGH+Br lambs or between the control and +Br lambs. The +bGH lambs (+bGH and +bGH+Br lambs pooled) contained significantly greater proportions of lean and bone compared with the −bGH lambs (control and +Br lambs pooled). Although carcass composition was altered by bGH treatment, the distribution of individual tissues (lean, bone and fat) was not influenced significantly.Carcass quality was improved markedly by bGH treatment: subcutaneous fat depth was reduced and the area of the m. longissimus lumborum increased. +bGH carcasses would be ranked one fat class less on the Meat and Livestock Commission fatness scale than −bGH carcasses at the same carcass weight.