bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses to variations in dietary energy intakes by growing pigs 3. Effect of level of intake of diets of differing protein and fat content on the performance of growing pigs
Authors: Davies J. L. , Lucas I. A. M. 
Published: September 2010

SUMMARYThree diets were given separately, each at four levels of digestible energy (DE) intake, to gilts, castrates and boars growing from 21 to 92 kg live weight. The energy levels were those suggested by the Agricultural Research Council, compared with a 5% increase or 10% or 20% decreases in daily allowance. One diet (ME 18) had 3·0 Meal DE/kg and 18·2% crude protein; the other two (HE 16 and HE 19) had 3·26 Meal DE/kg and 16·1% or 19·3% crude protein.They were given unchanged throughout the experiment. Responses to change in daily DE intake were not affected by sex or diet, except in shoulder fat thickness. Feed eaten per kg gain did not vary by more than 4% over the intake levels investigated, and no difference was significant. On average, each reduction in daily intake below the ARC+5% allowance led to an increase of 1·2 percentage units of carcass lean and a decrease of 1·3 percentage units of carcass fat.In comparison with HE 16, the higher protein diet HE 19 gave improved feed conversion efficiency and growth rate, particularly in gilts. It did not cause significant changes in carcass measurements. In comparison with ME 18, HE 19 gave more efficient conversion of DE to weight gain, and faster growth.Boars required less feed per kg gain and had faster growth rates and leaner carcasses than gilts, which were superior to castrates. There was a high incidence of unpleasant odour in fat from boars, but some was also detected in that from gilts and castrates.
Effects of isolation, confinement and competition for feed on the energy exchanges of growing lambs
Authors: Webster A. J. F. , Smith J. S. , Brockway J. M. 
Published: September 2010

SUMMARY1. Calorimetric evaluation of the nutritive value of feeds for ruminants has, of necessity, involved using mature sheep isolated in respiration chambers. This experiment was designed to examine how such information relates to growing lambs reared in different ways.2. Lambs were either completely isolated, individually fed, or fed in groups. Two lambs in each group were fed to gain 100 g/day (medium) and two to gain 200 g/day (high). Calorimetric measurements were made on individuals or groups at intervals over 20 weeks.3. All lambs fed to gain 100 g/day consumed their entire ration, isolated lambs gained on average 123 g/day and the others 160 g/day. On the ‘high’ ration isolated lambs ate less than the others and gained 178 as against 228 g/day.4. Metabolizable energy intake, heat production and thus energy retention were similar in all groups offered the ‘medium’ ration. Differences in energy retention on the ‘high’ ration were related to differences in intake.5. The net availability for weight gain of the diet (kf) estimated from energy balance trials conducted throughout the growth period (0·61) agreed well with that predicted from its content of metabolizable energy (0·63).6. Estimates of the caloric density of the weight gain suggested that on the ‘medium’ ration the isolated lambs retained substantially more energy as fat than those reared in groups. These observations are discussed in relation to the design and interpretation of calorimetric experiments to predict the nutritive value of feeds for growing lambs.
An evaluation of beef carcass quality 1. The influence of cereal feeding on the growth and carcass quality of Friesian steers
Authors: Hinks C. E. , Prescott J. H. D. 
Published: September 2010

SUMMARYTwenty-four Friesian steers, initially 5 months of age, were involved in a 2 × 2 factorial experiment which spanned grazing and silage feeding periods of 22 weeks' duration. In the first period, cattle were stocked at a uniformly high density, with half of the group being fed 1·25 kg/head per day of supplementary barley. In the second period, the cattle were subdivided into four groups and fed varying levels of barley with silage. Finally all the animals received 3·65 kg/head per day of barley. Replicates of the four treatments were slaughtered at random after 5 to 11 weeks on this treatment. Whilst supplementary cereal feeding significantly increased the live-weight gains of steers at grass by 11%, this live-weight advantage was offset by their slower gains in the final weeks before slaughter. Feeding cereals to grazing cattle had little effect on carcass composition or the proportions of carcass joints, but their beef was considered, by a tasting panel, to be more tender than the meat from the control steers.Increasing the level of barley fed with silage only increased live-weight gains by 2%, and had little effect on carcass or meat quality.
A note on factors affecting puberty in Clun Forest female lambs
Authors: Dýrmundsson Ó. R. , Lees J. L. 
Published: September 2010

SUMMARYIn 1971 the attainment of puberty in 30 early-born and 30 late-born Chin Forest female lambs was studied. The early-born lambs showed their first oestrus at a mean age of 265·4 days and a mean body weight of 41·4 kg; the late-born lambs at 222·0 days and 36·8 kg.Marked individual variation existed in both age and body weight at puberty within the groups, largely because of differences in growth rate during rearing. Early-born singles showed their first oestrus on average 3·4 days earlier than twins while this difference between lateborn singles and twins was 17·9 days. Since early-born lambs attained puberty at a considerably higher mean age and heavier mean body weight than late-born lambs with similar growth rates it is suggested that the daylight environment experienced by the lamb may be a critical factor in regulating the onset of breeding activity.
Development of a model of voluntary food intake and energy balance in lactating cows
Authors: Forbes J. M. 
Published: September 2010

SUMMARYVoluntary intake of a range of feeds by cows is predicted on the assumption that the cows will satisfy their energy requirements unless physical limitations intervene. Predicted patterns of intake throughout lactation agree generally with observed changes, including an eventual plateau in body weight due to a predicted physical equilibrium between abdominal fat and gut contents. An attempt to incorporate a depression in milk yield when physical limitations prevented energy requirements being met by food intake was successful only with good quality feeds.
The feeding value for beef cattle of lucerne cobs differing in maturity and date of harvest
Authors: Horton G. M. J. , Holmes W. 
Published: September 2010

SUMMARYThe feeding value of four batches of dried lucerne cobs was compared in two experiments with beef cattle. The cobs were prepared from primary growths, cut early (LI) and late (L2), and from second-cut (L3) and third-cut (L4) material.In Experiment 1, intakes and digestibilities of the four cuts, offered as the sole feed, were measured using six British Friesian steers in two (3 × 3) Latin squares. The intake of lucerne cobs decreased as the digestibility of organic matter and cellulose increased, to result in similar intakes of digestible organic matter for all treatments.In Experiment 2, 32 beef cattle were given rolled barley and the lucerne cobs in the ratio of 1: 2 at two levels, plus barley straw ad libitum. The treatments were compared in eight (4 × 4) Latin squares. Similar daily gains were supported by diets containing LI, L3 and L4. Performance on diets containing L2 was significantly poorer at both levels of feeding.
Growth depression and food requirements of fattening pigs at low environmental temperatures when housed either on concrete slats or straw
Authors: Verstegen M. W. A. , van der Hel W. , Willems G. E. J. M. 
Published: September 2010

SUMMARY1. Four experiments, each with two groups of eight pigs, were performed in a controlled environment room equipped with two pens. One pen had straw as bedding and the other had slats. The animals were exposed to temperatures of about 17°C at the initial weight (20 to 25 kg). The temperature was lowered by about 1°C per 10 kg body-weight increase, to 8 to 12°C at the end of the fattening period (80 to 100 kg).Animals on slats were kept 4·7 to 5·3°C below the calculated zone of thermoneutrality and the animals on straw 2·0 to 2·6°C above the lower limit of thermoneutrality. In Experiments 1 and 2 the animals in both pens received the same amount of food per day and in Experiments 3 and 4 animals on slats received more food to give the same body·weight gain as on straw. Feeding level on straw was about 93 g/kg0·75 per day.2. In Experiments 1 and 2, body-weight gain on slats was reduced due to the lower effective temperature. After adjusting for feeding level, the reduction in daily gain was calculated as 18·5 and 11·8 g per °C below thermoneutrality. In Experiments 3 and 4 the extra food needed to maintain the same rate of gain on slats as on straw was respectively 18·1 and 45·5 g per °C below thermoneutrality.3. Carcass length of animals on slats was less than on straw.
Evaluation of three- and four-breed cross litters and pigs sired by purebred and crossbred boars
Authors: Fahmy M. H. , Holtmann W. B. 
Published: September 2010

SUMMARYBoars from four pure breeds and three two-breed crosses were mated at two stations to sows from six two-breed crosses to produce three- and four-breed cross litters. Two types of three-breed crosses were produced either using purebred boars or by partial backcrossing using crossbred boars. From the 504 litters produced 965 male pigs were slaughtered at 90 kg live weight. The purebred boars produced litters which were 0·4 and 0·2 pigs larger and 0·14 and 1·14 kg heavier at birth and 21 days respectively than the crossbred boars. Differences between pigs sired by purebred and crossbred boars were negligible for growth rate and carcass quality. Little difference was also found between three- and four-breed cross pigs sired by crossbred boars (except for daily gain, P < 0·05). Breed of dam was a significant source of variation on all the traits except dressing-out percentage. Significant breed of sire effect was found on all the traits related to carcass quality but not on those related to growth. Breed of sire × breed of dam interaction was significant on backfat thickness, carcass lean yield percentage and average daily gain. The best crosses in carcass value were those of Duroc boars mated to Hampshire-Landrace and Landrace-Yorkshire sows, while those pigs with the fastest gain were from Landrace boars ×Duroc-Yorkshire sows and Duroc-Yorkshire boars × Large Black-Lacombe sows.
A note on the effect of omitting the cereal supplement from a finishing diet offered to weaned single-suckled calves
Authors: Broadbent P. J. 
Published: September 2010

SUMMARYWeaned single-suckled calves (male castrates) were offered a finishing diet which included 2·3 kg/day bruised barley (F) or a similar diet with the cereal supplement omitted (R) during the main winter feeding period. Some diet R steers had a subsequent grazing period and were re-housed for a second winter when the diet included a cereal supplement. The treatments caused differences in growth rate, distribution of slaughterings and grazing requirements. Diet R reduced growth rate and the steers took longer to reach slaughter, which was at a higher live weight, than on diet F at the same degree of finish. Steers on diet R produced 4·5% more carcass weight, 8·2% more lean, 4·1 % less fat and 11·2% more bone than those on diet F. They consumed more wet distillers' grains (21·1 %), swedes (25·5%) and grass silage (32·0%) from housing to slaughter but saved 80·0 % of the cereal consumed on diet F.
Food intake and grazing behaviour of sheep varying in body condition
Authors: Arnold G. W. , Birrell H. A. 
Published: September 2010

SUMMARYHerbage intake and grazing times were measured in four experiments in which adult sheep grazed short and long pastures. The digestible organic matter (DOM) intake of adult wooled Merino and Corriedale wethers was higher, both absolutely and per kg live weight, when they were lower in live weight due to prior under-nutrition. The relative differences were similar on both abundant and scant pasture and were proportional to the relative differences in live weight. The higher intakes were achieved by differences in the time spent grazing and in the rate of intake per hour of grazing. DOM intake of shorn sheep was increased by up to 44% per kg live weight within 5 weeks of shearing in two experiments when the mean temperature was 8°C but no increase in DOM intake was observed in four other experiments when the mean temperature was 11°C. Shorn sheep achieved higher intakes on both abundant and scant pastures by increasing intake per hour of grazing.
Artificial rearing as a system for evaluating male lambs
Authors: Davies D. A. R. , Owen J. B. , Read J. L. 
Published: September 2010

ABSTRACTThe use of an artificial rearing system to provide controlled environment conditions for performance testing of male lambs was investigated in two trials. A sample of lambs from 5 fat-lamb sire breeds was included.Performance during the initial restricted milk-feeding period was uniform but large differences in solid food intake gave variable performance in the adjustment period immediately following weaning. Lambs were evaluated from 40 days onwards in terms of growth rate and efficiency of food conversion. Some breed differences were significant and the variation within groups was sufficiently high to suggest that performance might be improved by within-group selection.Estimates from Trial 2 show that food conversion efficiency was related to growth rate, but early and late performance in the evaluation period were not correlated (r = 0·12, 0·16 and 0·14 for growth rate, food intake and efficiency, respectively). Some refinements of the method are suggested, and it is concluded that the system could provide suitable conditions for testing male lambs at an early age without the variable influence of the dam.
The electrical conductivity inside the bovine vaginal wall
Authors: Feldmann F. , Aizinbud E. , Schindler H. , Broda Hanna 
Published: September 2010

ABSTRACTElectrical conductivity was measured during the oestrous cycle of cows with electrodes implanted in the vaginal wall. Conductivity was considerably higher during oestrus than during the preceding or following cycle stage. Conductivity was also high in the fresh surgical wound, whereas the healing process was accompanied by a decrease.
A note on bovine colostrum as an alternative source of immunoglobulin for lambs
Authors: Logan E. F. , Foster W. H. , Irwin D. 
Published: September 2010

ABSTRACTNewborn lambs were separated from their dams before they had an opportunity to suck. They were given bovine colostrum in a single feed and thereafter fed on a milk substitute. Their weight gain compared favourably with that of lambs fed on ovine colostrum followed by milk substitute or suckled naturally. It was concluded that bovine colostrum can be used successfully as an alternative source of immunoglobulin for rearing lambs.
The effect of two concentrations of dietary protein and of formaldehyde-treated soya-bean meal on the performance of high-yielding dairy cows
Authors: Kaim M. , Neumark H. , Folman Y. , Kaufmann W. 
Published: September 2010

ABSTRACTIn two experiments, 165 dairy cows were allotted to groups given post-partum dietsad libitumcontaining either 150 g (LP) or 190 to 200 g (HP) crude protein (CP) per kg dry matter (DM).In experiment 1, which lasted 21 weeks after calving, cows were given pre-partum two amounts of energy (National Research Council (NRC) recommended amountv.1·4 × NRC recommended amount). Pre-partum amounts of energy did not affect DM intake, milk yield or milk composition. Protein intake, including that for maintenance, was 84 and 116 g CP per kg milk in the LP and HP groups, respectively.During 2 to 6 weeks after calving the HP concentration in a diet containing 850 g concentrates and 150 g hay per kg, decreased DM intake, whereas in a diet containing 650 g concentrates and 350 g hay per kg, the HP concentration increased DM intake. During weeks 12 to 21 after calving, the HP concentration decreased milk yield from 33·0 to 28·7 kg and increased milk fat concentration from 24·1 to 29·3 g/kg. Rumen fluid ammonia-N concentrations were 135 and 200 mg/1 in cows given the LP and HP diet, respectively. Plasma urea-N concentrations were 114 and 172 mg/1 in the same groups, respectively.In experiment 2, three groups of cows were given, during 15 weeks after calving, diets LP, HP and HP containing soya-bean meal treated with formaldehyde (HPSP). Protein intake, including that for maintenance, was 71, 82 and 86 g CP per kg milk in the three groups, respectively. Mean daily milk yields during 15 weeks after calving were 37·5, 39·2 and 39·3 kg in groups LP, HP and HPSP, respectively. Cows given the LP and HP diets lost, after parturition, 22·5 kg body weight, whereas cows given the HPSP diet lost only 6·0 kg. Rumen fluid ammonia-N concentrations were 95, 175 and 81 mg/1 and plasma urea-N concentrations were 80, 200 and 143 mg/1 in cows given the LP, HP and HPSP diets, respectively. It is concluded that on certain diets high-yielding dairy cows can be given, in addition to that for maintenance, as little as 60 g CP per kg milk. Formaldehyde-treated soya-bean meal may increase milk yield during the first 3 weeks after calving, and reduce body weight loss.
The effects of dose and method of administration of biosynthetic bovine somatotropin on live-weight gain, carcass composition and wool growth in young lambs
Authors: Johnsson I. D. , Hathorn D. J. , Wilde R. M. , Treacher T. T. , Butler-Hogg B. W. 
Published: September 2010

ABSTRACTExogenous bovine pituitary somatotropin (GH) can influence markedly body composition in fattening lambs. However, neither the effects of biosynthetic somatotropin nor the effects of dose and method of administration have been reported. Fifty Dorset-cross lambs (female and castrated male) were given concentrate ad libitum and treated between 10 and 22 weeks of age with biosynthetic bovine somatotropin either dissolved in buffer and injected subcutaneously (s.c.) in proportion to body weight (0·025, 0·1 or 0·25 mg/kg per day), dissolved in buffer and continuously infused s.c. (0·1 mg/kg per day) or suspended in olive oil and injected s.c. (0·1 mg/kg per day), and compared with 10 untreated control lambs. Somatotropin had little effect on live-weight gain (controls = 228 g/day; final live weight 37 kg), food intake and food conversion efficiency, and only marginally increased the weight of muscle and bone dissected from the shoulder joint. The weights of the major fat depots in the abdominal cavity and of fat dissected from the shoulder joint were linearly related to dose of somatotropin (P < 0·001). Lambs given the highest dose had less visceral fat (1·18 v. 2·84 kg; P < 0·001) and proportionately less fat (285 v. 374 g/kg; P < 0·001) and more muscle (542 v. 447 g/kg) and bone (172 v. 149 g/kg; P < 0·001) in the shoulder joint than control lambs. There was a positive curvilinear relationship (P < 0·01) between clean wool growth (mid-side patch sample) and dose; lambs injected daily with 0·1 mg somatotropin per kg grew one-third more wool than control lambs. Method of administration affected plasma somatotropin profiles but had no significant influence on any of the responses measured. The anabolic actions of somatotropin may have been limited in this experiment by a low sodium concentration in the diet. It is concluded that the lipolytic/anti-lipogenic effect of somatotropin can occur in the absence of conditions conducive to the stimulation of muscle protein deposition and that the response is dose dependent but not influenced by method of administration of the hormone.
Effects of dam and sire group on the propensity for twin calving in cattle
Authors: Morris C. A. , Day A. M. 
Published: September 2010

ABSTRACTThe incidence of twin calvings and double ovulations was studied in two Milking Shorthorn herds and one Friesian herd, each with above-average annual twin calving rates (average 0·031, compared with a national rate of 0·01). The proportions of double ovulations were calculated from records comprising 1237 cow × years (cows over 2·0 years of age); means were 0·08, 0·27 and 0·50, for three groups which had previously produced 0, 1 or >1 sets of twins, respectively. All cows (whether still present or no longer in the herd) were then allocated a twin production status, to indicate the number of twin sets (0, 1 or >1) produced, or produced so far, in their lifetime. There were records from 1559 cows, with sire and dam also known. Twin production status was significantly influenced by dam group (P < 0·01), i.e. the twin production status of the cow's dam. Sires were classified into two groups, according to whether any daughters had produced two or more sets of twins. After allowing for ascertainment, sires in the two groups were found to differ (P < 0·01) by 0·06 in the probability of their daughters producing at least one set of twins in their lifetime (i.e. 0·08 to 0·14). One sire and dam combination in particular had prolific daughters with a probability of 0·39 of producing at least one set of twins in their lifetime (compared with a probability of 0-07 for the other extreme combination). The possibility of these observations being explained by the segregation of a single recessive gene was considered, but the necessary interaction between sire group and dam group was not significant.
Development of a dynamic, mechanistic model of lamb metabolism and growth
Authors: Sainz R. D. , Wolff J. E. 
Published: September 2010

ABSTRACTA dynamic, mechanistic model of lamb metabolism and growth was developed for the purpose of evaluating hypotheses regarding the mechanisms of action of growth promotants. The model relates tissue growth to DNA accretion and protein turn-over. State variables include circulating amino acids, glucose, lipids and acetate; four protein pools (carcass, viscera, other tissues and wool) and storage triacylglycerol are also included. Equations are mainly of the Michaelis-Menten form, allowing for nutrient utilization patterns to be determined by relative tissue affinities for substrates (ko.5), enzymatic capacities (Vmax) and substrate concentrations ([S]). Protein degradation rates are defined as first-order with respect to protein. The model adequately simulated growth from 20 to 40 kg empty body weight. Simulated changes in nutrient input yielded reasonable energy balance response patterns, although theoretical growth efficiencies were greater than those observed in practice. Variations in volatile fatty acid absorption patterns were accommodated well, with predicted nitrogen retention closely approximating experimental observations. The model also responded appropriately to changes in dietary protein level, with body fat varying inversely with amino acid absorption. In summary, the model was found to perform adequately for the purpose of examining mechanisms responsible for alteration of growth and body composition.