bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of plane of nutrition during rearing on growth, production, reproduction and health of dairy cattle. II. Growth to maturity
Authors: Crichton J. A. , Aitken J. N. , Boyne A. W. 
Published: September 2010

1. The four systems of rearing dairy heifer calves, described in Part 1 of this series are now studied for their effect on absolute and relative growth rates to maturity.2. Data on live-weights and measurements and the percentages of mature size attained by these at 44, 80, 104, 132, 182, 260 and 312 weeks of age are tabulated.3. In all groups the measurement to reach maturity earliest was circumference of metacarpus followed in order by length of back, height at withers and width of hooks.4. By 6 years of age all groups had attained approximately the same body size. Maturity in the LL group in terms of four skeletal measurements was delayed by only 9 months, and in the case of HL and LH animals by 5 and 4 months respectively.5. All groups showed the same general pattern of relative growth but the effect of restricted feeding was to increase at the younger ages the difference i n percentage of mature size between early and late maturing measurements. After 44 weeks of age the rate of growth was most rapid in those measurements which were furthest from maturity then.6. The rate of tissue deposition was markedly increased in high plane animals during early pregnancy compared with low plane. Evidence is presented to show that much of this was lost during lactation.7. At first oestrus, animals in all four treatment groups had reached the same percentage of mature size for each body dimension (except for length of back in the LL group).8. From data on 5 animals it is shown that although growth in height at withers and length of back ceased by 6 years of age there was slow but continuous growth in live-weight, middle and heart girths and width of hooks to 9 years of age.
The feed intake of grazing cattle. I. Feed intake of dairy cows on strip and free grazing
Authors: Holmes W. , Osman H. El Sayed 
Published: September 2010

1. Eight Ayrshire milk cows were grazed for four 3-week periods from July to October 1957 in a balanced sequence on two strip-grazed and two free-grazed paddocks, each of two acres. Feed intake and digestibility were estimated by the chromic-oxide faecal-nitrogen method.2. There was no significant difference in average feed digestibility between the treatments. Free grazing cows ate 30·4 lb. dry matter per day and strip grazing cows 28·9 lb. The difference was just significant (p<0·05). There was no significant difference in milk yield, live-weight or live-weight gain per cow.3. Total feed output per acre was 11% greater on strip grazing when measured by utilised starch equivalent but only 1 % greater when measured by estimated feed consumption. The data suggest that strip-grazed cattle needed less energy for grazing.4. The results are discussed with reference to their accuracy, their implications on grazing management and their correspondence with estimates of food requirements based on indoor feeding standards.
Progeny testing dairy bulls at different management levels
Authors: Robertson Alan , O'Connor L. K. , Edwards J. 
Published: September 2010

1. Records used to compile the Contemporary Comparisons of 57 Friesian, 8 English Ayrshire and 11 Scottish Ayrshire A.I. bulls, each with at least 100 ‘effective daughters’ were analysed.2. For each bull, the herd-years were divided into three equal groups on the basis of the average heifer yield of both daughters and contemporaries (high-, medium-, and low-producing herd-years) and three independent Contemporary Comparisons were calculated for each bull, one at each of the three yield levels.3. In the data from England and Wales, the mean Contemporary Comparison declined with increasing mean level of production. This decline was such as to imply that some 20% of the differences in production between herds were genetic in origin. A possible explanation lies in the gradual change from Dairy Shorthorn to Friesian and Ayrshire which has taken place in England and Wales, but not in Scotland, during the last 15 years.4. The variance within progeny groups within herd-years increased from the low level to the high but the coefficient of variation decreased slightly. The variance between sires also increased with the mean level of production but almost exactly in parallel with that within sires so that the heritability and consequently the accuracy of the progeny test for milk yield was effectively the same at all production levels.5. The correlation between the true breeding values of the bulls at the different levels was very close to one.6. From these results it is concluded that there is no need to provide special strains within breeds to suit particular management levels or to concentrate progeny testing in the higher-producing herds and that daughter records from all herds, irrespective of level of production, can be used with equal confidence.
Rearing lambs on a synthetic diet
Authors: Cunningham J. M. M. , Edwards R. A. , Simpson Margaret E. 
Published: September 2010

Twenty-two triplet or small twin lambs were reared in two ways. One group received cow's milk and the other a synthetic milk designed to approximate in composition to ewe's milk.The group fed synthetic milk made significantly better live-weight gains to weaning. This difference was not maintained after weaning. Possible reasons for this are discussed.
The effect of semen volume and number of spermatozoa on the fertility of intra-uterine inseminations of pigs
Authors: Hancock J. L. , Hovell G. J. R. 
Published: September 2010

Forty-eight sows were inseminated into the uterus with semen (sperm fraction) diluted to 20 ml. with an egg-yolk glucose phosphate (YPG) diluent to contain 10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa. In 24 sows (120 ml. group) insemination of the 20 ml. diluted semen was followed by the intra-uterine insemination of 100 ml. YPG diluent, alone. The success of insemination was judged at autopsy from ova recovered 2-4 days after insemination (Experiment A) or from counts of foetuses present 25 days after insemination (Experiments B and C). In Experiment A the numbers of ‘cleaved’ ova were recorded before fixation: the numbers of ova judged to be ‘fertilised’ were counted in preparations of fixed and stained ova. For 24 sows inseminated with 20 ml. semen alone at the three dosage levels (10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa) the percentages of ‘cleaved’ and ‘fertilised’ ova were 78·5 and 80·9; 83·5 and 81·2; 24·6 and 19·8. For sows inseminated with the same sperm numbers in 20 ml. semen followed by 100 ml. diluent, the percentages were 41·5 and 43·9; 44·2 and 36·2; 24·6 and 6·7. Comparison of numbers of sows with some ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) showed no significant differences in sow fertility between treatments.Comparison of numbers of sows with all ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) shows that inseminations with the 20 ml. volume, alone, were of significantly higher fertility than those inseminated with 120 ml.Estimates of fertility based on the examination of unfixed ova differed in 9 sows from estimates based on the examination of fixed and stained ova. In one sow some uncleaved ova were shown to be pronucleate after fixation and staining. Morphologically abnormal ova were identified in 6 sows; most of these abnormal ova showed multinucleate blastomeres. These abnormal ova were found only in sows inseminated with not more than 1·0 × 109 spermatozoa.Counts of the numbers of spermatozoa on fixed ova showed that these tended to decline as the number of spermatozoa inseminated declined. Comparing sows inseminated with the same number of spermatozoa there tended to be fewer spermatozoa on ova from sows inseminated with 120 ml. than on ova from sows inseminated with 20 ml.Of 13 sows in Experiment B inseminated with 20 ml. semen containing 10·0 × 109 spermatozoa, 9 had foetuses present at autopsy 25 days later (11·6 foetuses per sow).Of 17 sows in Experiment C inseminated with 20 ml. semen containing 1·0 × 109 spermatozoa, 7 had foetuses present at autopsy 25 days later (7·1 foetuses per sow).The difference in pregnancy rate for the two groups is not statistically significant.Differences in litter size between the two groups of sows are explainable by differences in ovulation rate between the two groups (group B, 18·2 corpora lutea per sow, group C, 13·4 corpora lutea per sow).
The causes of differences in production between dairy herds
Authors: Brumby P. J. 
Published: September 2010

The extent of the genetic differences existing among a sample of the dairy herds of New Zealand was assessed by a direct experimental approach. In part one of the experiment, 240 young calves were taken from 40 herds of markedly different production levels and reared and milked as a uniformly treated herd of cattle at Ruakura. In part two of the experiment 120 sets of identical twin calves were divided amongst these 40 high- and low-producing herds.Results indicated that in general there were no obvious genetic differences between the cattle in the high and low herds in body size, fertility, milk production or days in lactation. There were, however, genetic differences between the high and low herds in milk composition; approximately 50% of the differences between herds in butterfat and protein content and 25% of the SNF content were due to genetic differences between herds.Genetic differences between herds in yield were found within the high group of herds but not in the low.Evidence was obtained indicating that interactions between herd environment and the genotype of individual animals provided an appreciable source of variation.The production level of a herd in which an animal was reared was without effect upon its subsequent production potential for milk yield.
Compensatory growth and sexual maturity in mice
Authors: Monteiro L. S. , Falconer D. S. 
Published: September 2010

The effects of environmental factors in the pre-weaning period on the subsequent growth of mice were studied. The variance caused by maternal effects, i.e. by environmental factors common to litter-mates, increased from birth to 4 weeks of age (1 week after weaning) and then decreased by about 60% between 4 and 8 weeks. Furthermore, a high litter weight at 4 weeks was followed by low subsequent growth and vice versa. The occurrence of compensatory growth from 4 weeks onwards was thus established. In contrast, the genetically determined variation of body weight did not show any reduction during the period of compensation, but increased up to 8 weeks of age.The modification of the growth curve, by which compensation was achieved, was then studied. It was found that the inflexion point separating the initial phase of exponential growth from the subsequent phase of asymptotic growth corresponded closely with the attainment of sexual maturity in females, as judged by the opening of the vagina. Sexual maturity was reached at approximately the same weight in all litters, but at widely different ages. Thus, litters with rapid early growth as a result of a good maternal environment reached sexual maturity and consequently entered the asymptotic phase early, while litters with slow early growth entered the asymptotic phase late. Compensatory growth was therefore achieved through curtailment or prolongation of the exponential phase of growth.
Ground roughage in the diet of the early-weaned calf
Authors: Leibholz Jane 
Published: September 2010

SUMMARYAn experiment was conducted with 60 male Friesian calves between 5 and 11 weeks of age. The experiment was a 5×2×2 factorial design. The five major treatments were the inclusion of 20 or 40% ground wheat straw or 20, 40 or 60% ground lucerne in a pelleted diet. A methane inhibitor was included in the diet given to 30 of the calves. The diets were given alone or with a chaffed wheat straw supplementad libitum. All diets contained 2% sodium bicarbonate.The weight gain of the calves was greater with the diets containing ground lucerne than with those containing ground wheat straw, but in both cases weight gains were reduced with increasing roughage content of the diets. The efficiency of feed conversion showed a similar trend. The supplementation of the diets with chaffed wheat straw did not affect the performance of the calves. The inclusion of the methane inhibitor in the diets improved the weight gains and efficiency of feed conversion. The daily retention of nitrogen in the calves showed a similar trend to the growth rates.The molar percentage of acetate in the rumen increased as the roughage content of the diets increased while the proportions of propionate, butyrate and valerate decreased. The inclusion of the methane inhibitor in the diets decreased the concentration of total volatile fatty acids (VFA) in the rumen and increased the molar percentage of propionate, butyrate and valerate.
Effect of diurnal air temperature cycles on growth and food conversion in pigs
Authors: Morrison S. R. , Heitman H. , Givens R. L. 
Published: September 2010

SummaryIn trials with 64 pigs growing from 37 to 60 kg or from 65 to 88 kg growth rate and food conversion were not affected by either a 10°C or a 20°C range in diurnal air temperature cycle compared with a constant temperature equal to the mean of the cycle when the mean temperatures were optimal. However, with a constant temperature and cycle mean at 6°C above optimum, performance declined with a 20°C range cycle.
The influence of pellet size and density on the intake by calves of dried grass pellets given as supplements to hay
Authors: Tetlow R. M. , Wilkins R. J. 
Published: September 2010

ABSTRACTHigh (1·31 kg/1) or medium-density (1·17 kg/1) dried grass pellets of 9, 12 or 18 mm diameter were given to British Friesian male calves of 7 to 14 weeks of age as supplements to chopped hay (Experiment 1). Pellets were given ad libitum but with access limited to two periods of 1½ h per day, and hay was given ad libitum for the remaining 21 h. In Experiment 2, high (1·34 kg/1) or medium-density (1·14 kg/1) dried grass pellets of 18 mm diameter were given to British Friesian male calves of 26 to 30 weeks of age. Pellets were given as supplements to chopped hay as in Experiment 1.There was no effect of pellet size or density on total intake of organic matter or live-weight gain by calves in either experiment. With the exception of animals given pellets of 12 mm diameter in Experiment 1, animals in both experiments consumed less pellets of high density than of medium density, but they were able to compensate for low pellet intake by eating more hay.The coefficients of variation for intake were higher in Experiment 1 than in Experiment 2, and higher for the intake of pellets than for total intake. There was a progressive increase in the intake (g organic matter/kg M0·75 per day) by calves in Experiment 1, whereas in Experiment 2 intake increased for the first 10 days and then remained constant. On average the proportion of pellets and hay consumed did not change in Experiment 1, but in Experiment 2 the proportion of pellets in the feed consumed increased from 53·5 to 60·6%.
Digestibility of whole barley and oat grains by cattle of different ages
Authors: Morgan C. A. , Campling R. C. 
Published: September 2010

ABSTRACT1. Three trials were conducted to investigate in cattle of different ages the digestibility of whole barley and whole oat grains in diets with approximately a 1:1 ratio of hay to concentrates. The cattle used were four 17-month-old steers in Trial 1; four non-lactating cows in Trial 2; and six heifers at 7, 10, 13 and 16 months of age in Trial 3. 2. Steers and cows completely digested the starch in the rolled cereals and the steers digested more of the starch of whole barley than the cows. The digestibility of starch in whole oats was high (0·72) and similar in both types of cattle.3. The heifers when 7 months of age had the highest coefficients of starch digestibility for both whole barley and whole oats (0·62 and 0·83 respectively). Digestibility of starch declined with age, but this effect was masked by variations within and between animals at different ages. It is concluded that barley should be rolled before feeding but with oats the benefits from rolling are likely to be small and possibly only worth while when given to adult cattle.
Effect of high-protein supplements on the utilization of body reserves by single-suckling cows
Authors: Chestnutt D. M. B. 
Published: September 2010

AbstractIn three successive experiments 32, 30 and 32 autumn-calving, single-suckled cows were subjected to individual planned weight reductions over winter on silage-based diets with various levels of concentrate supplement. At a similar level of weight loss, milk yield and calf gain were increased when protein supplements of low rumen degradability were given. On average, the inclusion of 0·75 kg fish meal in the diet improved calf gain by 0·13 kg/day. Results are discussed in terms of the effect of protein supplement on the efficiency of use of body reserves.
In vitrogas and foam production by rumen fluid from cows of genetically high or low susceptibility to pasture bloat
Authors: Cockrem F. R. M. , McIntosh J. T. , McLaren R. D. , Morris C. A. 
Published: September 2010

AbstractRumen fluid was obtained from rumen fistulated cows (two of high (HS) and two of low (LS) susceptibility to bloat) which were bred in experimental herds subjected to long-term divergent genetic selection for pasture bloat susceptibility. In vitro fermentation using strained rumen fluid from each cow with various pasture juice substrates showed no differences between HS and LS in gas production per unit of rumen fluid or in foam production per unit of gas production. Fluid from cows on grazed pasture produced greatest gas volumes. Clover juices produced more foam of similar stability to ryegrass and mixed pasture juices. Foam production per unit of gas was greater for all juices when the rumen fluid was from cows grazing bloat potent pasture.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight 4. Partitioning of dissected and chemical fat in the body
Authors: Thompson J. M. , Butterfield R. M. , Perry Diana 
Published: September 2010

AbstractChanges in the partitioning of both dissected and chemical fat were examined from birth to maturity, in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. The partitioning of fat between six dissected and 11 chemical fat partitions in the body was examined in 34 mature animals, and the maturing patterns for these fat partitions calculated relative to the weight of total body fat, using the mean values for the mature animals and individual data from 106 immature animals.Strain had no effect on the partitioning of dissected fat in the mature animals, but did affect the partitioning of chemical fat in the bone and pelt partitions. Mature ewes had greater proportions of dissected subcutaneous and kidney fat, and lower proportions of dissected intermuscular and scrotal/udder fat, than the mature rams.There were significant strain and sex effects on maturing patterns for dissected subcutaneous and intermuscular fat. Strain and sex effects were also significant for the maturing patterns of some chemical fat partitions.Selection for high or low weaning weight had little effect on the partitioning of either dissected or chemical fat when compared at the same stage of maturity of total fat. There were large differences in the partitioning of both chemical and dissected fat between the rams and the ewes when compared at either the same weight of total fat, or the same stage of maturity of total fat in the body.
The digestible and metabolizable energy of two fat blends for growing pigs as influenced by level of inclusion
Authors: Wiseman J. , Cole D. J. A. 
Published: September 2010

AbstractTwo fat blends differing in free fatty acid concentration and fatty acid composition were included in cereal-based diets at concentrations of 10, 30, 50, 70, 90 and 110g/kg. The digestible (DE) and metabolizable (ME) energy of each diet were estimated in a metabolism experiment based on three 4 × 4 Latin squares using gilts of 30 kg initial live weight fitted with indwelling bladder catheters. With increasing dietary fat both DE and ME increased linearly (P < 0·001) and the linear equations derived were used to calculate the DE values of the two fats by extrapolation. Values were 26·4 and 24·2 MJ/kg respectively for fats A and B. The change in dietary D E and ME to increasing dietary fat concentration showed a curvilinear trend (P = 0·0987 and 0·1268 respectively for DE and ME ) indicating that fats may not be correctly evaluated at only one rate of inclusion. The quadratic functions derived were interpolated to provide DE and ME data for the two fats. Values for DE for fat A ranged from 32·7 o t 25·7 MJ/kg at 10 and HOg/kg, and for fat B from 38·6 to 26·3 MJ/kg at 10 and 110 g/kg. Data for ME followed similar trends. It was concluded that multi-level assays are important in the evaluation of fats and that the rate of decline of fat DE and ME was specific to the fat examined.
The effect of diet in winter on the body composition of young steers and subsequent performance during the grazing season
Authors: Baker R. D. , Young N. E. , Laws J. A. 
Published: September 2010

AbstractFriesian steer calves born in August were reared from 3 to 7 months of age on silage alone (S) or on silage and concentrates to supply metabolizable energy (ME) in the proportion of 0·5: 0·5 (55) or 0·1: 0·9 (19). The mixed diets were either offered to appetite (55A and 19A) or restricted to provide the same energy intake as the S group (55R and 19R). The cattle were then grazed for a 6-month period as a single group. During the winter the S, 55R and 19R groups had similar live-weight gains. Despite having the highest nitrogen intakes the S group deposited less protein, but more fat than the other two groups. There were no significant differences within A or R groups, but the A groups had higher live weights, empty-body weights and carcass weights than the R groups and had more fat and less protein per kg empty body weight at turn-out to grazing.Compensatory growth was exhibited by the S, 55R and 19R groups during the grazing season. It arose because of differences in intake and not because of differences in the energy content of the gain. Intake was inversely related to the level of fat per kg empty body weight at the start of grazing. There was no evidence that the nature of the diet in winter had an effect on subsequent herbage intake.It was concluded that diet per se in winter had no residual effect on intake at grazing, but that it did have direct and residual effects on the relative deposition of fat and protein which could lead to an association between the level of fat in the empty body and intake. Inefficient use of nitrogen from silages with moderate fermentation characteristics was also demonstrated.