bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of station and field tests for the improvement of milking performance in dairy cattle. IV. Culling effects in herd and station records
Authors: Hinks C. J. M. 
Published: September 2010

SUMMARYThe effects of culling, natural wastage and different correction and exclusion procedures on estimates of lactation parameters have been examined in test station records of 1042 Danish Red cows. A total culling rate of 20% was applied to the initial material, of which 11% represented obligatory culling for disease, injury and infertility and 9% ‘paper’ culling for performance at four different stages of lactation.Exclusion and correction of short records generally resulted in overestimates of the sample mean and underestimates of the selection differential produced by culling. In all instances, the variance of the sample prior to culling, and the loss of variance attributable to culling, was underestimated in samples containing short or corrected records.It was concluded that field data cannot provide material suitable for objective studies of selection and that a reappraisal of the effects of age, lactation, season, etc., in the controlled conditions of test stations may well be justified. An absence of culling in test stations contributes to the large estimates of variance and heritability characteristic of station material.
The development and structure of, and seasonal change in, the coat of some Wiltshire sheep
Authors: Ryder M. L. 
Published: September 2010

SUMMARYCoat and skin samples were taken monthly from three Wiltshire ewes for two years, and then fortnightly between the spring equinox and the autumn equinox of 1968.The fleece comprised kemp and wool, having a weight of 1·1 kg and a length of 50 mm. In summer all the primary fibres had a latticed medulla, and although the secondaries were smaller than the primaries, they were relatively coarse and often medullated, over one-third having a latticed medulla at the peak period. The overall mean S/P ratio was 3·5.Follicle development was studied in four lambs from birth to 84 days. Only 27% of the secondaries lacked fibres at birth, and all had fibres at 14 days. There was a trend of increasing medullation in the primary fibres. Shedding primary follicles were seen from birth onwards, and shedding secondaries from 28 days, although obvious casting of the birth coat did not begin until 84 days (at the beginning of June).There was a basic seasonal cycle of follicle activity starting in March and lasting until September; inactivity began in September, reached 100%, and continued at this level until March. Subsidiary cycles suspected from the monthly samples were confirmed by the fortnightly samples. Thus peaks of inactivity in June and August separated three cycles of growth of two months duration. Only 80% of the primaries and 50% of the secondaries became inactive in June, with 50% of the primaries and 30% of the secondaries, in August.
Testing regression models for pig feeding systems
Authors: Dent J. B. , English P. R. , Raeburn J. R. 
Published: September 2010

SUMMARYRegression equations have been tested relating average daily gains in pigs to average daily intake of crude protein, lysine, and TDN for each of three growth stages. The tests were based on output contour curves representing 1 lb, 1·4 lb and 1·75 lb live-weight gain per day in the three stages. On each contour, while crude protein intake was held constant, points were selected to represent the economically optimum combination of lysine and TDN intakes, a ‘high energy-low lysine’ combination and a ‘low energy-high lysine’ combination. For the latter two points, least cost mixes of feed ingredients were computed. Four feed mixes were computed at the economically optimum combination of lysine and TDN intakes. Comparisons were made between the performance of pigs given the six different mixes to assess the validity both of the slope of the output contour and its position and to examine the influence on growth performance of the ingredient specification of diets formulated to the same nutrient levels.Using the six diets formulated on each contour, 12 feeding systems were developed all of which theoretically would take the pig from 50 to 200 lb in the same number of days. Six of these systems maintained the same diet type for each period; the others involved a change of diet type at least once during the three stages of growth. Diets formulated to meet the economically optimum combination of nutrients based largely on maize and groundnut meal stimulated inferior daily gains compared with alternative formulations. Both diets with a larger percentage of their lysine supplied from synthetic sources (the economically optimum combination based on maize and groundnut meal, and a low energy-high lysine combination) led to inferior daily gains. Pig performance was generally poorer than expectation, particularly from 50 to 150 lb live weight.No differences could be attributed to differing ingredient composition in equi-nutrient diets. Similarly, no significant differences in growth rate were found between those systems which maintained a constant diet type throughout the three stages of growth. Pigs on systems which involved a change in diet type from one stage of growth to another grew in general slower than those pigs which had a fixed-diet type throughout.Pigs on both diet combinations with a high percentage of weatings (a high cost formulation and a low energy-high lysine combination) had the best carcass results.
Beef production from grass and silage with autumn-born calves. 1. The influence of grazing intensity on efficiency of herbage utilization and live-weight gain of cattle
Authors: Wilkinson J. M. , Prescott J. H. D. 
Published: September 2010

SUMMARY1. Two experiments are described in which groups of 12 autumn-born calves were strip-grazed at different intensities. In Experiment 1 (1966), ‘standard’ and ‘high’ grazing intensities were compared. In Experiment 2 (1967), ‘standard’ and ‘low’ intensities were compared. In both experiments the same meadow fescue—ryegrass ley provided 0·24 ha per head for grazing and conservation; herbage surplus to grazing requirements was conserved as silage.2. The grazing season was divided into three parts according to the type of grazing, and estimates were made of daily herbage allowances, herbage quality, efficiency of herbage utilization and the live-weight gain of the cattle.3. Grazing intensity was regulated by controlling daily herbage allowances by strip-grazing. Within grazing seasons, differences in grazing intensity had little effect on the digestibility of the herbage dry matter on offer. Dead herbage accumulation was low (10%) in the early and late parts of the season, but rose to 25% in mid-season.4. The efficiency of herbage utilization was estimated in three ways: from sample cuts of herbage on offer and refused; from measurements of herbage intake; and from feeding standards for maintenance and gain. Efficiency was highest for the ‘high’ group of Experiment 1 and lowest for the ‘low’ group of Experiment 2. The validity of efficiency estimates is discussed in relation to measurements of pasture yield, herbage intake and the assessment of the nutrient requirements of growing cattle.5. Live-weight gain over the whole season was 0·59 and 0·89 kg/head per day for the ‘high’ and ‘standard’ groups of Experiment 1, respectively. In Experiment 2, the ‘low’ and ‘standard’ groups gained weight at 0·95 and 0·84 kg/head per day, respectively.
Crossbreeding Sinhala cattle with Jersey and Friesian in Ceylon
Authors: Wijeratne W. V. S. 
Published: September 2010

SUMMARYA crossbreeding trial was conducted in the hot wet tropical zone of Ceylon at Karagoda-Uyangoda. Sinhala cows were mated to Jersey, Friesian and Sinhala bulls. A few reciprocal matings were done with the Jersey breed.The milk yields of the Friesian crosses were higher than those of the corresponding Jersey crosses which were higher than those of the Sinhala. The ½ Sinhala ½ Friesian also had a longer lactation and larger body size than the Jersey cross or purebred Sinhala. A decline of about one-third of the milk yield of the F1was evident in the F2generation.The liability to perinatal mortality increased from the F1generation calves to F3calves.
A comparison of the performance of suckled lambs with lambs weaned at seven weeks of age and either grazed or given concentrates
Authors: Rutter W. 
Published: September 2010

SUMMARY1. Seventy-two Blackface ewes with 96 Greyface (Border Leicester ♂ × Blackface ♀) lambs were allocated to three groups. Twenty-four ewes with 32 suckling lambs were set-stocked on 2·4 hectares (ha) of grass (A); 32 lambs were weaned and set-stocked on 2·4 ha of grass (B) and 32 lambs were weaned, housed and given concentrates (C). Beef cows with calves were used to control the grass in the two grazing groups.2. The average initial live weight of the lambs was 18 kg. Treatments had a significant effect on performance, the live-weight gains per lamb over the initial 35 days being 11·2, 9·1 and 5·9 kg for groups A, B and C respectively. The total gains over 70 days, when the suckled lambs (A) were weaned, were 17·6, 15·5 and 14·3 kg.3. The total live-weight gain per ha from lambs and calves over 88 days was higher on treatment B than on treatment A. The lambs weaned on to grass took 9 days longer than the suckled lambs to reach a slaughter weight of 42 kg and had significantly poorer killing-out percentages.4.The lambs given concentrates had an overall food conversion efficiency of 4·89 kg concentrates per kg live-weight gain.
The voluntary intake and utilization of roughage–concentrate diets by sheep. 1. Concentrate supplements for hay and straw
Authors: Crabtree J. R. , Williams G. L. 
Published: September 2010

SUMMARYFour levels of a proprietary concentrate (0, 100, 200 and 400 g/day) were offered to Welsh Mountain ewe lambs receiving hay or straw ad libitum for 14 weeks. The apparent digestibility of the energy and nitrogen in the various diets was determined in a concurrent digestibility trial.The voluntary intakes of the straw and hay dry matter when given alone were 242 and 451 g/day respectively (28·4 and 49·2 g/kg W0·73 per day). Straw intake increased with an increase in concentrate feeding up to a level of 25% concentrate in the total dry matter and then declined. Hay intake declined linearly with increasing concentrate level (3 g/day decline per unit increase in the percentage of concentrate). In each case the total intake of dry matter and digestible energy increased with an increase in concentrate level.There was a positive within-treatment relationship between initial live weight and voluntary intake, an additional 0·019 Meal ME/day being consumed per kg increase in live weight. Within treatment groups lambs consuming relatively more food also made relatively higher weight gains. Estimates based on published standards of the metabolizable energy intakes required to produce the live weight changes observed on each treatment were considerably higher than the intakes recorded in the trial.
Influence of breed and sex on the allometric growth patterns of major bovine tissues
Authors: Mukhoty H. , Berg R. T. 
Published: September 2010

SUMMARYThe influence of breed and sex on relative growth patterns of muscle, bone and fat in beef cattle has been investigated. Comparisons were made of growth coefficients estimated using Huxley's (1932) allometric equation relating muscle, bone or fat to muscle plus bone using data from the dissection of half carcasses of 63 young bulls, 106 steers and 22 heifers representing a number of breed groups. Growth coefficients for muscle and for bone were found to be similar among different breed groups of bulls, steers and heifers. The proportion of muscle increased and that of bone decreased as the size of animal, measured by muscle plus bone, increased. Muscle and bone weights adjusted to common muscle plus bone weights were significantly different among breed groups within sex. Differences in amount of muscle relative to bone were therefore established at earlier stages of growth and maintained over the period represented in the present study.Growth coefficients for fat were significantly different among breed groups within sexes.Sex within breed group had no statistically significant influence on growth coefficients for muscle or for bone. Muscle and bone weights adjusted to a common muscle plus bone weight were similar for sex groups within all breed group comparisons. Sex did not have a marked effect on rate of fattening since differences between growth coefficients for fat (between sexes, within breeds) were not statistically significant—although in all comparisons growth coefficients for fat were lowest for bulls, intermediate for steers and highest for heifers. Sexes differed in weight of fat adjusted to common muscle plus bone weight, heifers being fatter than steers and steers fatter than bulls, a difference probably resulting more from early onset of the fattening phase in heifers, followed by steers, rather than relative rate of fattening.
Artificial insemination and natural service at a predetermined time in cyclic sheep treated with ‘SC-9880’-progesterone sponges
Authors: McClelland T. H. , Quirke J. F. 
Published: September 2010

SUMMARYResults are given of an experiment in which 61 cyclic Finnish Landrace × Dorset Horn ewes were synchronized for oestrus by intravaginal treatment for 14 days using sponges impregnated with 30 mg ‘Cronolone’ (9a-fluro-11-hydroxy-17a-acetoxy-progesterone; SC-9880, G. D. Searle) and 400 mg progesterone. Groups of 31 and 30 sheep were inseminated twice, either artificially or naturally, at predetermined intervals of 48 and 58 hr after sponge withdrawal. All 61 ewes were in oestrus within 48 hr of removing sponges; 26 of 30 (87%) artificially inseminated and 29 of 31 (94%) hand-mated sheep conceived at the controlled oestrus. The incidence of multiple births was not significantly affected by the method of breeding.
Genetic and phenotypic parameters of body weights in Bikaneri sheep (Magra strain)
Authors: Chopra S. C. , Acharya R. M. 
Published: September 2010

SUMMARYHeritabilities of birth, weaning, 6-month and yearling weights adjusted for significant non-genetic factors and obtained from half-sib correlations were 0·10±0·03, 0·22±0·05, 0·37±0·09 and 0·48±0·07 respectively. Genetic correlations of birth weight with later weights were small and negative except with weaning weight. Genetic correlations among other weights were large and positive. The phenotypic correlations among these weights were positive and statistically highly significant.
A note on the performance of artificially reared lambs fed cold milk substitute from birth to slaughter
Authors: Penning P. D. , Bradfield P. G. E. , Treacher T. T. 
Published: September 2010

SUMMARYTwo groups of five lambs were removed from their dams within 48 hr of birth and artificially reared to a slaughter weight of approximately 32 kg on a milk replacer given cold, hay and concentrates. Voluntary intake of the feeds was recorded together with growth rates and carcass composition of the lambs.The two groups of lambs were slaughtered at 58 or 67 days of age with growth rates of 459 and 433 g/day, respectively. The mean milk replacer dry matter consumed per lamb was 34·9 kg and 39·3 kg and concentrate dry matter intakes were 3·1 kg and 4·1 kg. Intakes of hay were negligible. Food conversion efficiencies were 0·70 and 0·67 kg of live-weight gain per kg of dry matter consumed. The mean carcass weights were 18·1 kg and 19·5 kg with mean muscle, bone and fat contents of 48·7%, 16·2% and 35·1 % for lambs slaughtered at 58 days and 48·0%, 14·7% and 37·2% for those slaughtered at 67 days.
The energy and protein metabolism of pigs growing at a high ambient temperature
Authors: Holmes C. W. 
Published: September 2010

SUMMARY1. The experiment was designed to investigate the effect of growth at a high ambient temperature, 33–35°C, on the protein and energy metabolism of pigs, compared with 25°C. The high temperature caused an increase in rectal temperature of 1·4° to 1·7°C. The animals were given two low levels of feeding while growing between 25 and 70 kg live weight; energy and nitrogen retention were measured periodically.2. The apparent digestibilities of the dietary dry matter and energy were decreased and urinary nitrogen losses were increased at the high temperature. Heat production was increased at the high temperature, by between 2% and 10%, the effect becoming more pronounced during the course of the experiment. Retention of energy and nitrogen was reduced at the high temperature.3. The net efficiency of utilization of metabolized energy above maintenance was between 63% and 67%, and was not significantly affected by live weight or temperature. The results suggested that maintenance requirement was increased at the high temperature.4. Analyses of sample joints indicated that the high temperature caused an increase in fat percentage only at the higher level of feeding; this result agreed with fat and protein retention calculated from the balances.
The utilization by beef cattle of a cereal supplement given in liquid suspension or in the dry form
Authors: Renton A. R. , Forbes T. J. 
Published: September 2010

SUMMARYAn experiment was carried out in which a cereal supplement was given to beef cattle, either in suspension in water or as a dry supplement. There were no significant differences between treatments in live-weight gain, food intake or food conversion ratios. Although there was a tendency for the digestibility coefficients of all constituents to be lower on the diet containing the liquid supplement, the differences were not statistically significant. It is concluded that giving a supplement in suspension has no adverse effect on the utilization of the overall diet and could facilitate mechanization of the feeding operation.
Variation in the concentration of copper in the blood plasma of Finnish Landrace and Merino sheep and their crosses with reference to reproductive performance and age
Authors: Hayter Susan , Wiener Gerald , Field A. C. 
Published: September 2010

SUMMARYConcentrations of copper in blood plasma were determined in January and in February 1971 and in February and March 1972 in a grassland flock of sheep comprising the Finnish Landrace and (Tasmanian) Merino breeds and their reciprocal crosses. Numbers of animals ranged from 30 to 100. The unadjusted mean copper levels of the flock varied from 63 to 81 μg/100 ml. The Finnish Landrace had a markedly lower plasma copper concentration than did the Merino, the mean difference after adjustment for other factors varied from 16 to 54 μg/100 ml. First crosses had levels halfway between those of the parental breeds. Copper concentration fell in the 4-week period between February and March 1972 when most of the ewes were pregnant. This fall was greatest for the Finnish Landrace which started with the lowest level and least for the Merino.Neither the breed differences in the change in level nor the actual concentration appeared to be related to the number of lambs (0 to 4) carried by the ewes. Variation in copper level associated with the age of ewe, significant for the two bleedings in 1972, was largely attributable to the higher level among the youngest age class, approximately 10 months old when bled. The stage of pregnancy at the time of blood sampling, as reflected by date of lambing, did not significantly affect plasma copper concentration in this flock.
Cold-induced inhibition of thermal panting in shorn sheep. 1. Effect of intensity of cold exposure
Authors: Slee J. 
Published: September 2010

SUMMARYThe delayed onset of heat-induced panting (at 42°C) immediately following previous shearing and exposure to cold was studied in 54 Scottish Blackface and 53 Tasmanian Merino sheep.In control sheep (not previously cold-exposed) thermal panting commenced in 15 min. In cold-treated sheep, when the cold was intensified stepwise from +26°C (+30cC being thermoneutral) down to −10°C, using 2-hr exposures, or lengthened from 2 hr to 16 hr at +8°C, the delay (block) to panting increased non-linearly from 40 to 70 min.The minimum intensity of cold required to produce a block (26°C in Merinos, 22°C in Blackfaces) was similar to that inducing peripheral vasoconstriction. More intense vasoconstriction preceded longer blocks, but vasoconstriction sometimes occurred without a subsequent block.Merinos were more sensitive than Blackfaces to the blocking effects of cold, and, once blocked, the effect in Merinos was less easily removed by re-warming.The time taken for cancellation of the heat debt during heat stress could account for half the block. The remainder, a delay of about 30 min, was attributed to a specific inhibition of respiratory control in the central nervous system.
A note on the genetic variation in the fatty acid composition of cow milk
Authors: Edwards R. A. , King J. W. B. , Yousef I. M. 
Published: September 2010

SUMMARYThe fatty acid composition of milk samples from Ayrshire twin cows was determined. The results were in general agreement with those reported by other workers. Comparisons between the variation within pairs of one and two-egg twins showed that the proportions of different fatty acids are subject to a high degree of genetic control.
Rearing of dairy cattle. 4. Effect of concentrate supplementation on the live-weight gain and feed intake of calves offered roughages ad libitum
Authors: Leaver J. D. 
Published: September 2010

SUMMARYThe effects of three levels of concentrate supplementation on the live-weight gain and intake of roughages of 12-week-old British Friesian female calves were examined. Each supplement was offered for 12 weeks to two replicates of five calves which were group fed. The following six roughages were studied; high quality hay, dried grass wafers, grass silage, barley straw, poor quality hay and maize silage. The digestibility of the roughages was measured with sheep by total collection of faeces.Increasing the level of concentrate supplementation gave linear increases in live-weight gains of calves with all roughages, the greatest response occurring with roughages of low digestibility. The intake of roughage was depressed by increasing the level of concentrate supplementation, the greatest depressions occurring with roughages of high digestibility. Live-weight gains and roughage intakes were higher with dried grass wafers and lower with maize silage than would be expected from their respective digestibility coefficients.Multiple regression equations were calculated to relate live-weight gains or roughage intakes to concentrate intake and roughage digestibility. These equations predict from the digestibility of a roughage, the amount of concentrates required daily to produce a given live-weight gain, and the amount of roughage which is eaten under these circumstances.