bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of frequency of feeding on milk production of dairy cattle: an analysis of published results
Authors: Gibson J. P. 
Published: September 2010

ABSTRACTAutomated feeding systems for dairy cows offer the benefits of ‘little and often’ feeding. Published data were collected and analysed to establish the extent of such benefits. Twenty-three publications reporting the results of 35 experiments were examined. Several statistically significant positive responses indicated that milk fat concentration, and to a lesser extent yield of milk, could sometimes be increased by increasing the feeding frequency. However, for ail experiments the average proportional increases (± s.e.) in milk fat concentration and milk yield were fairly small at 7·3 (± 3·3) % and 2·7 (± 1·3) %, respectively. The responses of milk fat concentration and milk yield were apparently correlated (r= 0·43, s.e. = 0·20), and the mean proportional response of milk fat yield was 8·3 (± 3·1) %. There was no evidence that milk protein concentration, lactose concentration or changes in body weight were affected by changes in feeding frequency. Increases in food intake were sufficient to explain some, but not all, instances of increased milk fat production. All statistically significant responses to increased feeding frequency occurred when the milk fat concentration was originally depressed, milk fat depression generally being due to feeding pelleted or highly concentrated diets. Increases in milk fat concentration through increased feeding frequency were generally insufficient to bring the milk fat concentration up to a commercially acceptable level. All statistically significant responses were observed on moving from one or two to three or more meals per day, but the possibility of further responses beyond four meals per day could not be ruled out. It was concluded that cows producing milk of commercially acceptable milk fat concentrations were unlikely to benefit from increased feeding frequency.
Amino acid requirements of growing pigs 5. The interaction between isoleucine and leucine
Authors: Taylor S. J. , Cole D. J. A. , Lewis D. 
Published: September 2010

ABSTRACTThirty-two female growing pigs (25 to 55 kg live weight) were subjected to four dietary treatments combining two levels of isoleucine and two levels of leucine to investigate the effects of leucine supply on the requirement for isoleucine.Results for daily live-weight gain, food conversion efficiency and carcass quality judged by ham dissection indicated that 3·8 g isoleucine per kg diet was marginally adequate for the growing pig in diets containing 13·4 g leucine per kg. An interaction between dietary leucine and isoleucine was demonstrated. Increasing the dietary leucine concentration to 20·4 g/kg clearly resulted in a deficiency of isoleucine in the basal diet, as daily gain, food conversion efficiency and carcass quality were significantly improved by increasing the isoleucine concentration from 3·8 g to 4·5 g/kg diet. Dietary leucine concentration did not influence performance at the higher level of isoleucine supply. Changes in plasma urea and amino acid concentrations confirmed the findings from the growth experiment of the interaction between isoleucine, leucine and valine.
Amino acid nutrition of the lactating sow: limitation by indispensable amino acids
Authors: Wilkinson R. , Cole D. J. A. , Lewis D. 
Published: September 2010

ABSTRACTIn the first of two experiments of 6 × 6 Latin-square design a diet of barley, soya bean meal and fish meal, known to give an adequate lysine intake (56 g/day) at the level of feeding adopted, was diluted with maize starch to give crude protein intakes ranging between 448 and 923 g/day but with the lysine intake held constant by using synthetic lysine in the diets. The diets were given to sows suckling ten piglets between days 12 and 30 of lactation. Dietary amino acid adequacy was assessed by changes in plasma urea, urinary urea, urinary nitrogen and plasma amino acid concentrations. The dietary amino acid supply became limiting with a protein intake of approximately 730 g/day. In the second experiment, a diet of similar composition was used with varying additions of synthetic threonine, methionine, isoleucine and tryptophan: the control diet contained all the synthetic amino acids added, the basal diet none and the other diets were formed by adding groups of three out of the four synthetic amino acids. On the basis of some of the variables studied, it was concluded that, for this diet, threonine was the limiting amino acid after lysine.
Comparison of two methods for evaluating reproductive development in prepubertal gilts
Authors: Deligeorgis S. G. , English P. R. , Lodge G. A. , Foxcroft G. R. 
Published: September 2010

ABSTRACTTwenty-one pairs of litter sister gilts of similar live weight were selected at 150 days of age and one member of each pair was allocated randomly to the following treatments at approximately 170 days (80 kg live weight): 1. stimulation by mature boar; or 2. an intramuscular injection of oestradiol benzoate. The two groups were fed to appetite and slaughtered at approximately 180 days of age. Examination at slaughter indicated greater ovarian and uterine development in response to oestradiol relative to boar treatment (P < 0·01). The results indicate that oestradiol treatment of gilts followed by post-slaughter examination of the reproductive tract is a sensitive method for evaluating the effects of prior treatments on reproductive development. Significant family and pre-weaning growth effects on reproductive development were also evident on both evaluation methods.
Genetic effects on maternal performance and litter pre-weaning and post-weaning traits in rabbits
Authors: Lukefahr S. , Hohenboken W. D. , Cheeke P. R. , Patton N. M. 
Published: September 2010

AbstrtactFlemish Giant (FG) and New Zealand White (NZW) purebreds and terminal crossbreds (TX) (Flemish Giant sires × Florida White-New Zealand White dams) were evaluated during a 10-month period for maternal and litter pre-weaning and post-weaning performance. For the doe traits studied, teat number was greatest and litter interval was shortest, while body weight at breeding age (154 days), litter weight at 21 days and day 1 to 21 food intake were lowest for crossbred does. These traits were similar for pure doe groups, with the exception of body weight, for which FG does were heavier. For the preweaning litter traits examined (no. = 101 litters), litter size born was smallest in the TX group (the purebred groups being similar) and was largest at weaning (28 days) for NZW. Proportion of kits born alive was lowest in FG litters, while the NZW and TX groups were comparable. Litter and average birth and weaning weights, litter daily gain, and doe and litter food intake (1 to 28 days) were all highest in FG litters and lowest in TX litters. Repeatability estimates (t) were low (t < 0·05) for litter size and birth weight traits, and were moderate to high (0·18 < t < 0·58) for the remaining maternally influenced characters. For the post-weaning litter traits studied (no. = 86 litters), NZW litters were larger in number and heavier at market age (56 days), and consumed more food from 28 to 56 days than FG and TX litters. Purebred FG litters, however, had heavier average market weights per rabbit, while purebred NZW and TX litters were similar. Mortality due to respiratory disease was higher in FG litters than in NZW and TX litters. Total mortality incidence was lowest in the TX group.
The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights
Authors: Wright I. A. , Russel A. J. F. , Hunter E. A. 
Published: September 2010

ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.
Relationship of components of the body among mature cows as related to size, lactation potential and possible effects on productivity
Authors: Jenkins T. G. , Ferrell C. L. , Cundiff L. V. 
Published: September 2010

ABSTRACTAttributes of lactation and weight of components of the empty body were analysed to evaluate relationships between performance potential of various breeds or breed crosses and the proportion of empty-body components relative to slaughter weight. Differences in major internal organs attributable to breed, breed cross, level of food intake, mature body size and milk production potential were observed. Milk yield was positively related to proportion of lung tissue, tended to be positively related to head and liver tissues but was negatively related to the proportion of warm carcass. As estimated from a three breed diallel, significant additive breed direct effects were observed for several empty-body components. In general, heterosis tended to be non-significant for all proportions of body components with the exception of proportion of head, fore and hind feet and lung tissue. Breed crosses characterized as having greater potential for mature weight were heavier at slaughter and had a greater proportion of structural components such as head, hide and fore and hind feet. Differences among visceral organs associated with production potential for size and milk production are discussed relative to the possible effect on basal energy expenditure and the effect these differences may have on the energy requirements for a cow/calf livestock enterprise.
Rumen degradation of straw 1. Untreated and ammonia-treated barley, oat and wheat straw varieties and triticale straw
Authors: Tuah A. K. , Lufadeju E. , Ørskov E. R. , Blackett G. A. 
Published: September 2010

ABSTRACTThe dry-matter degradation of 19 varieties of barley, 14 varieties of wheat, 11 varieties of oats and one variety of triticale straws, both untreated and ammonia treated were studied using the nylon-bag technique. There were significant differences between the untreated varieties of all the types of cereal straw studied with respect to dry-matter loss (DML) values. When the barley and wheat straws were treated with ammonia, the differences between the varieties were also significant although ammonia treatment tended to improve those with lower values to a greater extent than those with higher values. There were also significant differences between the DML values of the oat straws when they were treated with ammonia but only after 48-h incubation. There was a significant negative relationship between the 48-h DML values of the untreated oat straws and the improvement in the DML values with ammonia treatment (r = −0·65; P < 0·05). Grain yield, straw length and nitrogen concentration had no significant relationship with the DML values of the untreated straws. Barley and oat straws had generally higher DML than the wheat and triticale straws.
The effect of frequency of feeding milk replacer to pre-ruminant calves on respiratory quotient and the efficiency of food utilization
Authors: Williams P. E. V. , Fallon R. J. , Brockway J. M. , Innes G. M. , Brewer A. C. 
Published: September 2010

ABSTRACTThirty-four British Friesian bull calves were used in experiments to identify diurnal patterns of respiratory quotient (RQ), as an indicator of substrate utilization and to measure energy balance when the same daily amount of milk replacer was given on either 1, 2, 4 or 6 occasions. Each calf spent two 4-day periods in an open-circuit respiration chamber followed immediately, in selected calves, by an 8-day period in a metabolism crate, period 1 starting when calves were 12 days of age and period 2 at 28 days of age. The amount of milk replacer given daily was 32 and 48 g/kg M0·75during periods 1 and 2 respectively.Neither rate of live-weight gain nor the energy balance of the calves was affected by frequency of feeding. However, raising the frequency of feeding from one to four times daily significantly affected the pattern of RQ. Reduced feeding frequency tended to raise the mean maximum and lower the mean minimum values of RQ; reducing the frequency of feeding significantly increased the range in RQ (F < 0·01).The apparent dry-matter digestibility of the milk replacer was higher in 36-day-old than in 20-day-old calves (0·93v.0·88; s.e.d. 0·011,P< 0·01). The effect was mainly due to an increase in the digestibility of fat (0·82v.0·73; s.e.d. 0·019). In 20-day-old calves, there was a linear increase in fat digestibility with increased frequency of feeding (P< 0·01) rising from 0·67 in calves given milk once daily to 0·85 when milk was given in six meals.The results suggest that calves given milk replacer once daily (at a level of intake of 32 rising to 48 g milk powder per kg M0·75) do not pass through a diurnal period of severe nutrient deprivation and that raising frequency of feeding would do little to improve efficiency of energy utilization.
The effect of feeding period and trenbolone acetate on the potential of culled dairy cows for beef production
Authors: Garnsworthy P. C. , Cole D. J. A. , Grantley-Smith M. , Jones D. W. , Peters A. R. 
Published: September 2010

ABSTRACTSixty-four Friesian/Holstein cows culled from dairy herds were selected for uniformity and general health. They were allocated to five groups of 12 on the basis of body condition and live weight excluding the two cows at each extreme. These four cows indicated the range of condition and live weight in the sample and were slaughtered at the beginning of the trial with one group of 12 cows. Of the remaining four groups, two were implanted with 300 mg trenbolone acetate (Finaplix, Hoechst) and two used as unimplanted controls; one implanted group and one control group were slaughtered after 60 days and the remaining cows after 100 days. All cows were individually fed to appetite on a pelleted diet of 500 g dried lucerne and 500 g barley per kg. After slaughter the left side of each carcass was cut into primal joints and then separated into fat, lean and bone.Implantation resulted in greater live-weight gains to 60 days (1·35 v. 112 kg/day, P > 0·05) and to 100 days (1·31 v. 0·92 kg/day, P < 0·01), greater lean meat production and an increase in the lean proportion of carcasses.Feeding cows for 100 days rather than for 60 days led to higher slaughter weights but daily live-weight gain decreased and food intake increased progressively between 60 and 100 days. Carcasses from cows slaughtered at 100 days had significantly higher lean, fat and bone weights (P < 0·01) but as a proportion of side weight only the fat proportion of the carcass was significantly increased (P < 0·05).It was concluded that the supplementary feeding of cull cows produced heavier carcasses but at these high rates of gain increased yield was at the expense of proportionately more fat in the carca?.s. This problem was partially countered by implantation with trenbelone acetate.
Predicted and realized responses to selection for an index of bone length and body weight in Scottish Blackface sheep 1. Responses in the index and component traits
Authors: Atkins K. D. , Thompson R. 
Published: September 2010

ABSTRACTA selection experiment with Scottish Blackface sheep was used to compare predicted and realized responses to selection. Three closed lines, of approximate annual size of 270 ewes and 10 rams, were maintained between 1956 and 1974, in which selection was at random, or for high and low values of an index of cannon-bone length at 8 weeks of age adjusted for body weight at the same age. An unselected base flock (1954-55) and the randomly selected line were used to estimate base population parameters, while the selected lines were used to estimate realized responses to selection.Heritabilities and genetic correlations were obtained in the unselected lines from a variety of collateral and ancestral relationships. The important components of phenotypic variance were estimated and likely responses to selection predicted for the index and its two component traits. Realized responses to selection were estimated from the regression of response on selection differential. The expected variance-covariance matrix of observed responses was included in generalized least-squares estimates of these regressions.The realized heritability of the index under selection, estimated from the divergence of selected lines, was 0·52 (s.e. 0·02). After allowing for the expected reduction in heritability arising from linkage disequilibrium, this was very similar to the base population estimate of 0·56 (s.e. 0·04). The responses in the component traits of the index were also very close to those expected from base population parameters
Flat v. step feeding of medium or high levels of concentrates for dairy cows
Authors: Poole D. A. 
Published: September 2010

ABSTRACTA system of feeding concentrates at a flat rate was compared with a step system in which the rate was reduced every 6 weeks. Each system was evaluated at either medium or high level concentrates. There were two trials involving 40 British Friesian cows for weeks 3 to 20 of lactation. The flat rate treatments were 71 (medium) and 9·3 kg dry matter (DM) per day (high) and corresponding step allocations were 8·8, 7·1 and 5·4 kg DM per day or 11·7, 9·3 and 7·0 kg DM per day. Silage was given to appetite. In trial 1 this was lucerne silage of moderate quality (metabolizable energy (ME) = 8·9 MJ/kg DM) and in trial 2 high quality grass silage (ME = 11·1 MJ/kg DM) was used.In the comparison between systems of concentrate allocation, food intakes, milk production and live-weight change were similar in each trial. In the comparison between medium or high levels of concentrates, silage DM intakes were similar in trial 1 (7·1 v. 7·0 kg/day) but not in trial 2 (9·8 v. 8·7 kg·day, P < 0·05), and milk yields were lower in trial 1 (19·0 v. 21·4 kg/day, P < 0·001) but not in trial 2 (24·1 v. 25·2 kg/day). Milk composition was similar for medium and high concentrate intakes in both trials. Cows given the medium level of concentrates had higher live-weight losses than those given the high level in trial 1 (–58 v. –24 kg, P < 0·01) and trial 2 (–22 v. –kg). When concentrates were given at the medium level with moderate quality silage several cows had acetonaemia. Also, this feeding combination, especially when concentrates were given at a flat rate, reduced the proportion of cows which conceived within a limited breeding period.
Iron-induced copper deficiency in calves: dose-response relationships and interactions with molybdenum and sulphur
Authors: Bremner I. , Humphries W. R. , Phillippo M. , Walker M. J. , Morrice P. C. 
Published: September 2010

ABSTRACTThe effects of dietary supplements of iron, molybdenum and sulphur on copper metabolism in calves were examined. In one experiment, 27 castrated male pre-ruminant Friesian calves were given a milk-substitute ration containing 0·9, 4·5 or 9 mmol iron per kg dry matter for 8 weeks. The iron supplements had no effect on liver copper retention. When 24 of these calves were then given a diet based on barley grains and barley straw containing 0, 4·5, 9 or 13·5 mmols iron per kg for up to 24 weeks, liver and plasma copper concentrations were greatly reduced in all iron-supplemented animals but no clinical signs of copper deficiency developed. Reduction in the dietary sulphur concentration from 88 o t 47 mmol/kg after 12 weeks did not prevent the iron-induced reduction in liver copper concentrations n i animals given 9 or 13·5 mmol iron per kg. Plasma copper concentrations increased in all iron-treated calves given the low-sulphur diets, except in animals given 13·5 mmol iron per kg. The results indicate that iron is a potent antagonist of copper metabolism in weaned calves and that its effects are probably independent of dietary sulphur supply.In a second experiment 20 Hereford × Friesian female calves were given diets with supplements of 2·7 mmol iron and 20 μmol molybdenum per kg, separately and together, for 41 weeks. Both supplements reduced liver and plasma copper concentrations but only in the molybdenum-treated animals were live-weight gains reduced. The rate of decline in liver and plasma copper concentrations tended to be greatest in animals given both supplements, indicating that additive action of these antagonists is possible.
Responses of lactating sows to food level
Authors: Eastham P. R. , Smith W. C. , Whittemore C. T. , Phillips P. 
Published: September 2010

ABSTRACTEighty crossbred sows, following a standard feeding regime in pregnancy, received daily either 2·0, 3·5. 5·0 or 6·5 kg diet containing 130 g digestible crude protein, 8·0 g lysine and 13·1 MJ digestible energy per kg over a 28-day lactation to produce variation in body fatness and live weight. Sows on the highest level of feeding gained 13 kg and lost some 3 mm backfat between farrowing and weaning; corresponding changes on the lowest level of feeding were –31 kg and –9 mm backfat. Live weight of the litter at weaning was positively related to sow daily food allowance in lactation, but the major benefit of increasing lactation food allowance was in reducing the rate of maternal body weight and fatty tissue loss. These effects were described by the regression equations: maternal live-weight change in lactation (kg/day) = —1·7+0·34 lactation food intake (kg/day); maternal backfat change in lactation (mm LJSP2) = —0·40+0·05 lactation food intake fkg/day). Sows ingesting less food in lactation catabolized proportionately more body tissue to maintain milk yield and piglet growth, although they achieved this imperfectly, having lighter litters at weaning. Calculation of an overall net balance, taking into account the need subsequently to replenish tissues catabolized in lactation and ensuring efficient rebreeding of the sow, favoured a lactation feeding strategy towards ad libitum.