bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in body composition of sheep selected for high and low backfat thickness, during periods of ad libitum and maintenance feeding
Authors: Afonso J. , Thompson J. M. 
Published: September 2010

AbstractCoopworth sheep from the high and low backfat selection lines and from one random-bred line developed at Invermay, New Zealand, were used to examine the interaction between the degree offatness of sheep and a period of maintenance feeding (from 20 to 35 weeks of age), in terms of total fat, carcass lean tissue, bone and viscera weights, relative to the empty body weight measured in computer-aided tomography scans. A similar study was done for weights of subcutaneous, intermuscular and internal (abdominal) fat partitions relative to total fat weight. During two a d libitum feeding periods (front 10 to 20 and from 35 to 43 weeks of age) changes in the same components relative to the ‘whole’ (empty body weight or total fat, depending on the case) were expressed in allometric terms.Only the allometric growth coefficient for total fat weight was significantly affected by the period of restricted feeding, decreasing after this period. No line or sex effect was observed on any growth coefficient. As a result, there were no changes in differences between treatments over the ad libitum feeding periods, with fat animals and females having significantly higher proportions of fat, while females also had a significantly lower proportion of intermuscular fat.During maintenance feeding, line and sex differences in dissectible component weights did not change significantly, except in terms of intermuscular fat, with the males showing an increasingly larger proportion than the females.
Optimum designs for breeding programmes under mass selection with an application in fish breeding
Authors: Villanueva B. , Woolliams J. A. , Gjerde B. 
Published: September 2010

AbstractA procedure for maximizing genetic gain (after a number of generations of selection) for a given rate of inbreeding or for a given coefficient of variation of response is presented. An infinitesimal genetic model is assumed. Mass selection is practised for a number of discrete generations. With constraints on inbreeding, expected rates of genetic progress (ΔG) are combined with expeced rates of inbreeding (ΔF) in a linear objective function (Ω = ΔG - μΔF). In addition, an expression to approximate the rate of gain at any generation accounting for changes in genetic parameters due to linkage disequilibrium and due to inbreeding is derived. Predicted gain is in general within 5% of that obtained from simulation. Thus, both ΔG and ΔF are obtained from simple analytical formulae. An equivalent function is used when the coefficient of variation of response (CV) is the parameter restricted (Ω = ΔG -μCV). Maximization of the objective function Ω for appropriate values of μ gives the optimum number of sires and dams selected when specific constraints on the level of inbreeding or the coefficient of variation of response are imposed. The method is applied to a practical situation in fish breeding. Optimum mating ratios and optimum numbers of sires selected are obtained for different scored population sizes and heritabilities. Results obtained with this procedure agree very well with results from simulation studies. The optimum number of sires increases with the size of the scheme and with more severe restrictions on risk. In the schemes considered, the optimum mating ratio is equal to 2 unless the constraint on the rate of inbreeding is severe, the size of the scheme is small and the heritability is low. In these situations the optimum mating ratio is equal to 1. The procedure is general in terms of generations of selection considered and in terms of parameters to be constrained. A large amount of computer processor unit time is saved with this method in comparison with simulation procedures.
The effect of previous body condition on appetite and associated insulin profiles in sheep
Authors: Sibbald A. M. , Rhind S. M. 
Published: September 2010

AbstractThe effect of previous level of body condition on appetite was studied in 47 housed Scottish Blackface ewes, which had been either thin (L: mean condition score 2·15, s.e. 0·030; no. = 24) or fat (H: mean condition score 3·15, s.e. 0·056; no. = 23) 8 weeks before the start of the experiment. The mean daily voluntary food intake (VFI) of a dried grass pellet diet was higher for the L than for the H ewes (2176 v. 1727 g dry matter per day; P < 0·001) during the first 6 weeks of the experiment (period 1). Over this time, live weights increased from 60·5 or 69·9 (s.e.d. 1·68) to 68·4 or 75·6 (s.e.d. 1·94) and condition scores increased from 2·84 or 3·16 (s.e.d. 0·057) to 3·13 or 3·38 (s.e.d. 0·071) for the L and H ewes respectively.At the end of the 6-week period, plasma insulin concentrations were measured in 10 ewes from each treatment (mean condition scores 3·15 (L) and 3·27 (H) (s.e.d. 0·091)) when fed both ad libitum and at a fixed level of 1200 g/day for consecutive 11-day periods (period 2). Mean VFI was higher for the L than for the H ewes (2191 v. 1661 g dry matter per day; P < 0·05) over the period of ad libitum feeding. There was no effect of feeding level (ad libitum v. 1200 g/day) on mean plasma insulin concentrations, but the mean basal plasma insulin concentration was higher in the H than in the L ewes (43·0 v. 29·0 mil per 1; P < 0·05). Fifteen minutes after the ingestion of a single 400 g meal, the plasma insulin concentration in the H ewes was higher than the mean prefeeding value (63·3 v. 41·7 mil per I; P<0·05) but there was no corresponding increase in the L ewes. The plasma insulin concentration 15 min after the intravenous administration of a single dose of 0·25 U per kg live weight of insulin ivas higher in the H than in the L ewes (1723 v. 1031 mil per 1; P < 0·01) but there were no differences between treatments in plasma glucose concentrations following insulin administration.It was concluded that previous body condition can affect contemporary VFI and this effect may be mediated by plasma insulin concentrations providing a long-term feedback signal to the brain. Keywords: body condition, food intake, insulin, sheep.
The nutritive value of Acacia saligna and Acacia salicina for goats and sheep
Authors: Degen A. A. , Blanke A. , Becker K. , Kam M. , Benjamin R. W. , Makkar H. P. S. 
Published: September 2010

AbstractAcacia saligna and A. salicina phyllodes, harvested in autumn from young and mature trees, were fed as sole diets to goats (20·3 (s.d. 4·8) kg; no. = 16) and sheep (32·6 (s.d. 4·9) kg; no. = 16). Crude protein of phyllodes from mature trees was 111 g/kg dry matter (DM) and from young trees ranged between 121 and 132 g/kg DM. Condensed tannins and ash content were about twice as high in young trees as in old ones and gross energy was higher in old trees than in young ones. DM intakes by goats from both tree species were low: 24·8 and 13·7 g/kg M0·75 per day for mature and young trees, respectively. Corresponding intakes by sheep were 20·4 and 11·5 g/kg M0·75 per day. Metabolizable energy intakes were up to 125 and 99 kj/kg M0·75 per day for goats and sheep, respectively and were higher for phyllodes from mature trees than for young trees. Goats lost up to 219 glday and sheep up to 346 g/day and both species were in negative nitrogen balance. DM, organic matter and energy apparent digestibilities were low for all diets but were generally higher for goats than sheep. It is concluded that neither A. saligna nor A. salicina could be used as a sole food for small ruminants because of low intakes and negative nitrogen balances. This appears to be due to high tannin content.
Analysis of an open nucleus breeding programme for Djallonkè sheep in the Ivory Coast. 1. Examination of non-genetic factors
Authors: Yapi-Gnaorè C. V. , Oya A. , Rege J. E. O. , Dagnogo B. 
Published: September 2010

AbstractData on Djallonke sheep collected from 1983 through 1992 on 29 participating farms of an open nucleus improvement programme and from the nucleus were analysed. Initial on-farm records on 14342 lambs and on-station records on 2551 ram lambs were edited down to 6605 for birth weight (BWT), 5857 for preselection (birth to 80 days) average daily gain (PSADG), 10417 for 80-day weight (WT80), 13054 for lamb survival at pre-selection, 1978 for 180 (WT180) and 849 for 365 (WT365) day weights. Year of birth, sire line, flock, month and season of birth had significant (at leastP< 0·05)effects on both on-farm and on-station weights and on lamb survival. Trait means were 2·2 (s.e. 0·02) kg for BWT, 69·6 (s.e. 1·26) g/day for PSADG, 9·1 (s.e. 0·05) kg for WT80, 19·7 (s.e. 0·24) kg for WT180 and 31·8 (s.e. 0·45) kg for WT365. Mean survival was 90 (s.e. 0·9) %. Single lambs were heavier at birth and at 80 days of age, grew faster to 80 days and were about 200 and 500 g heavier at 180 and 365 days respectively than multiple lambs. There was a large variation between flocks: flock means for WT80 varied from 6·4 to 12·0 kg (CV 0·21), with smaller flocks having generally the lowest means. Lambs born in the hot-rainy season had the heaviest birth and 80-day weights, whereas ram lambs born in the cool rainy and early hot-dry seasons had the heaviest 180- and 365-day weights. Lambs born during the cool months of July to October had the lowest survival rate. Multiplicative factors were found to be more appropriate for adjusting on-farm records for type of birth, management level, birth date, season of birth and ewe parity than additive adjustment factors.
Analysis of an open nucleus breeding programme for Djallonkè sheep in the Ivory Coast. 2. Response to selection on body weights
Authors: Yapi-Gnaorè C. V. , Rege J. E. O. , Oya A. , Alemayehu Nega 
Published: September 2010

AbstractA selection programme was set up in 1983 in the Ivory Coast to improve the growth and live weight of the indigenous Djallonkè sheep using an open nucleus breeding system. Selection was based on male individual weights at 80, 180 and 365 days of age. Multiple sires were used in farmers' flocks. Individual animal model, using average numerator relationship was used to estimate breeding values from which genetic trends were derived. This paper reports results of the analyses of 10 417 records of 80-day weights (WT80) of lambs born between 1984 and 1992 from 29 participating farmers, and 1978 and 849 records on 180- (WT180) and 365- (WT365) day weights, respectively, of lambs from the nucleus. Phenotypic trends exhibited substantial annual fluctuation during the study period. The heaviest weights were obtained in 1986 (10·1 kg) for WT80, 1984 (23·3 kg) for WT180 and 1985 (33·7 kg) for WT365. There was an annual decline of 152 g (P<0·05) in WT80 mainly (–180 g/year) due to negative environmental trend. The phenotypic and environmental trends for WT180 were –703 and –721 g/year, respectively, while the corresponding values for WT365 were –931 and –956 g/year. Overall mean weights of the ram lambs at the three ages were 9·9, 23·3 and 33·7 kg, respectively in the base year and 9·3, 17·8 and 28·2 kg, respectively in the final year. Breeding values increased by 28, 11 and 14 g/year for WT80, WT180 and WT365, respectively. Results of this study indicate that genetic progress can be made in growth performance of Djallonkè sheep if reasonable levels of animal management as well as selection pressure are maintained.
Effect of altering the non-structural: structural carbohydrate ratio in a pasture diet on milk production and ruminal metabolites in cows in early and late lactation
Authors: Carruthers V. R. , Neil P. G. , Dalley D. E. 
Published: September 2010

AbstractThe effect on digestibility, ruminal metabolites, microbial protein synthesis and milk production of manipulating the non-structural (NSC): structural (SO carbohydrate ratio in a predominantly pasture diet was investigated in cows in early (trial 1) and late (trial 2) lactation. Twenty-four cows in trial 1 and 15 cows in trial 2 were offered pasture only (P), 0·85 P plus 0·15 NSC/protein mixture (PR), and P plus an additional 0·1 (trial 1) or 0·15 (trial 2) NSC (PE) in a Latin-square arrangement. All diets were isonitrogenous and P and PR were isoenergetic. PE but not PR increased microbial protein synthesis and decreased ruminal ammonia and milk urea levels, compared with P. Efficiency of microbial synthesis (g N per kg digestible organic matter intake) was not altered by treatment. Treatments had minor effects on ruminal pH and no effect on volatile fatty acid concentrations. PE and PR did not affect milk yield or protein yield and decreased fat yield compared with P in trial 1. Milk yield was increased on PE and PR compared with P and was greater on PE than PR, in trial 2. Yields of fat and protein were higher on PE than on P and yield of protein was higher on PR than on P. The results suggest that increasing the ratio of NSC: protein by increasing total carbohydrate intake was more effective in improving nitrogen utilization in the rumen than was increasing the NSC: SC ratio without increasing carbohydrate intake.
The effect of supplementary light during winter on the growth, body composition and behaviour of steers and heifers
Authors: Phillips C. J. C. , Johnson P. N. , Arab T. M. 
Published: September 2010

AbstractIn two experiments the growth, body composition and behaviour of steers and heifers kept in a building with natural day length only (average 9·7 h/day, treatment N) were compared with similar groups of animals kept in identical housing with the day length artificially extended to 16 h/day, (treatment L). The effects were recorded for 126 days in steers and 180 days in heifers, with both groups of animals being slaughtered in March when the two experiments ended. There were no effects over the entire experiment on the growth rate or food intake of either steers or heifers. The growth of the steers was reduced in the first 2 weeks after the lights were switched on but they gained more weight to compensate over the next 8 weeks. Over the whole experiment there was no treatment effect on food conversion ratio for either steers or heifers but it was reduced for steers on treatment L over the first 10 weeks. Steers in treatment N produced fatter carcasses than those on treatment L. Ultrasonic scanning of the heifers showed that those on treatment N deposited more fatty tissue between autumn and winter and less between winter and spring compared with those on treatment L.The behaviour of steers on treatment L did not vary over the experiment but steers on treatment N changed their behaviour with season. They slept for more time in winter and less in spring. Over the whole experiment steers on treatment L slept less and spent more time lying ruminating than those on treatment N but the total time spent lying was not affected by treatment. In contrast, the heifers on treatment L lay down for longer than those on treatment N, suggesting that the effect of supplementary light on lying time, which has been observed previously with dairy cows, is confined to female cattle. Heifers on treatment L started mounting each other earlier than heifers on treatment N and, like the steers, they spent less time sleeping It is concluded that extending the photoperiod for cattle in winter reduced body fatness in both steers and heifers and increased the time heifers spend lying down but that there were no major effects on growth rate or food intake.
Control of luteinizing hormone secretion in ewes by endogenous opioids and the dopaminergic system during short seasonal anoestrus: rôle of plane of nutrition
Authors: Forcada F. , Lozano J. M. , Abecia J. A. , Zarazaga L. 
Published: September 2010

AbstractThe role of endogenous opioids and the dopaminergic system on the inhibition of luteinizing hormone (LH) secretion during early and late anoestrus, together with its modulation by the plane of nutrition were investigated in ewes with a short anoestrous season. In early anoestrus (22 March; day 0), two groups of ovariectomized, oestradiol-treated adult Rasa Aragonesa ewes, maintained under natural photoperiod at 41°N, were given enough food to provide 1·4 × (high; H; no. = 6) or 0·5 × (low; L; no. = 6) energy requirements for maintenance. The effects of administration of the opiate receptor antagonist naloxone (1 mg/kg at four 1-h intervals) (day 15) and of the dopaminergic2 receptor antagonist pimozide (0·08 mg/kg) (day 21) on LH secretion were assessed. A second experiment was carried out in late anoestrus (21 June) using the same protocol. A significant increase in LH pulse frequency after naloxone treatment for both H and L groups was detected in late anoestrus. Number ofLH pulses after naloxone injections in early anoestrus also increased in H (P < 0·05) and L ewes (P = 0·08). The effect of pimozide injection on mean LH pulse frequency was greater in early than in late anoestrus, especially in ewes receiving a high plane of nutrition (P < 0·05 and P = 0·07 for H and L ewes, respectively in April and P = 0·07 for H ewes in July). A significant increase of LH pulse amplitude was also detected in early anoestrus in H ewes (P < 0·01). These results provide evidence that endogenous opioid mechanisms are involved in the inhibition ofLH pulsatile release both in early and late anoestrus in ewes with a short seasonal anoestrus. The ability of pimozide to increase LH pulse frequency in early anoestrus could be enhanced by a high plane of nutrition in the breed studied.
Rumen microbial production estimated either from urinary purine derivative excretion or from direct measurements of 15N and purine bases as microbial markers: effect of protein source and rumen bacteria isolates
Authors: Pérez J. F. , Balcells J. , Guada J. A. , Castrillo C. 
Published: September 2010

AbstractFour ewes fitted with ruminal and duodenal T-piece cannulae were each given six diets in a 6 × 4 factorial design. Diets or experimental treatments consisted of two ratios of forage: concentrate (700:150 (LC) and 400: 600 (HO). Forage was ammonia-treated straw and the concentrate was formulated with barley supplemented with one of three protein sources: sunflower meal, soya-bean meal or fish meal. Duodenal flows ofdigesta were estimated by the dual-phase technique using Co-EDTA and Yb acetate as liquid and solid markers. Microbial nitrogen (N) was estimated from the digesta flow of purine bases and 15N enrichment using as reference samples, bacterial isolates from the liquid (LAB) or solid (SAB) phase of rumen digesta.Duodenal flow of purine bases (mmol/day) was lower on LC (12·9) than HC (17·7) diets but in both treatments it was depressed by fish meal (12·3) compared with either soya-bean (17·3) or sunflower meal (16·3) as supplements (s.e. 1·13). Urinary excretion of purine derivatives showed a similar trend, 8·6 v. III mmol/day in LC and HC respectively and 8·8 v. 10·4 and 10·5 mmol/day in fish meal, soya-bean and sunflower meal diets (s.e. 0·56), respectively. Variation in excretion of urinary purine derivatives was mainly associated with digestible organic matter intake with an average ratio of 1·7 (s.e. 0·11) mmol per 100 g digestible organic matter intake. Irrespective of the microbial marker used, microbial yield was higher in animals offered HC than in those offered LC and with soya-bean or sunflower meal compared with fish meal supplemented diets. The microbial purine bases/N (mmol/g) ratio varied between LAB (1·99, s.e. 0·092) and SAB (1·69, s.e. 0·071) isolates leading to different estimates of microbial-N yield (g) from duodenal purine bases (7·76 (s.e. 2·84) v. 9·13 (s.e. 3·24)), urinary excretion of allantoin (5·57 (s.e. 2·0) v. 6·57 (s.e. 2·03)) or total purine derivatives (6·43 (s.e. 2·39) v. 7·56 (s.e. 2·77)). Urinary excretion of allantoin or total purine derivatives provided consistently lower estimates of duodenal microbial-N than duodenal purine bases or 15N, although it closely reflected the pattern observed in direct measurements.
Tissue mobilization rates in male fallow deer (Dama danta) as determined by computed tomography: the effects of natural and enforced food restriction
Authors: Jopson N. B. , Thompson J. M. , Fennessy P. F. 
Published: September 2010

AbstractThe breeding season in temperate species of deer is characterized by the rut, a period of intense sexual activity when the male eats very little and competes for access to females. Males have been reported as losing proportionately up to 0·30 of live weight over a 6- to 8- week period. The majority of the live-weight loss is accounted for in loss of depot fat, with smaller losses in muscle reserves. The effects of body composition, hormone status and season on these changes in fat and muscle reserves were examined in mature fallow bucks (Dama dama).The experiment was conducted in two stages, the ‘rut’ (February to May), and ‘spring’ (June to November). For the ‘rut’ period, bucks were randomly allocated to either ad libitum feeding, entire (HiEnt), matched group feeding, castrated (CAST), or entire bucks restricted to 7·6 kg dry matter per week (LoEnt) treatment groups (no. =4, 4 and 6, respectively). Three bucks from each of the HiEnt and LoEnt groups were selected for the ‘spring’ period. Bucks were given food ad libitum until mid October, whereupon they were restricted to 2·5 kg dry matter per week for 4 weeks (SPRING). Group food intake and individual live weights were measured weekly throughout both, periods. Body composition was measured by computed tomography on five and three occasions during the ‘rut’ and ‘spring’ stages, respectively.Comparisons of the relative losses of total fat and muscle relative to empty body weight (EBW) using the allometric model (y = aXb) revealed significant treatment differences. HiEnt bucks had a high relative rate of fat and a low rate of muscle mobilization (b = 5·23 and 0·38, respectively). Only the CAST group had lower (P < 0·1) b coefficient for fat than the HiEnt group at 2·79. The LoEnt group was the only group in which the b coefficient for muscle (at 1·07) was not significantly lower than 1·0. Visceral organ weight was lost at the same rate as EBW across all treatments. There was no net loss or gain of bone for any treatment group as the b coefficients were not significantly different from zero. Fat depots were analysed relative to the total fat depot using the allometric model. The HiEnt group displayed a pattern of fat mobilization whereby the external depots were mobilized at the greatest relative rate and the internal fat depots at the lowest rate (b coefficients were 1·86, 1·23 and 0·68 for the subcutaneous, intermuscular and internal fat depots, respectively). CAST and SPRING groups were not significantly different from HiEnt bucks in the relative mobilization of fat depots. All fat depots in the LoEnt group were mobilized at the same relative rate as total fat, as the b coefficients were not significantly different from 1·0.