bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feeding behaviour of pigs in groups monitored by a computerized feeding system
Authors: Young R. J. , Lawrence A. B. 
Published: September 2010

AbstractElectronic feeding systems for progeny testing pigs, allow selection to occur under conditions found on commercial farms. This paper reports on the feeding behaviour of six groups of 10 pigs, balanced for sex and initial body weight (mean starting and finishing weight: 32·1 kg v. 68·5 kg), monitored on such a system, for an average of 38 days. These data represent 26 542 feeder visits for which the pen, identity of the pig, feeder entry and exit times, and the amount of food consumed are known. The results show significant time-of-day effects for frequency of feeder visits, feeding rates, mean feeder occupation time, mean food intake per feeder visit, total food intake and total feeder duration (all P < 0·001). A single peak in feeding behaviour was observed between 13·00 and 16·00 h. Significant pen effects were observed on all feeding variables (e.g. feeder occupation times P < 0·05) with the exception of total food intake (P > 0·05). Individual pigs were found to possess different types of meal regulation, as measured by prandial correlations. Pens were found to have significantly non-random sequences of feeder entries (e.g. yen 1, P < 0·001). The range of feeder visits (three to 69) observed, was higher than reported in any previous study. Physical performance on the system, in terms of gain in body weight and total food intake was best predicted by total feeder occupation time, suggesting that individual pigs could adapt to the physical and social constraints imposed by the system, by altering aspects of their feeding behaviour. The results suggest that feeder access competition resulting from social synchrony and facilitation strongly influenced the feeding behaviour of pigs on this computerized food intake recording system.
Immunomodulatory approaches for regulation of growth and body composition
Authors: Flint D.J. 
Published: September 2010

AbstractHormonal growth promoters (growth hormone (GH), β-adrenergic agonists, steroids) which improve growth rate and/or lean: fat ratios in the carcass have received considerable adverse publicity and are either banned or have no licence for their use in countries of the European Community. This has led to the development of a number of techniques, involving the use of antibodies, aimed at regulating metabolic processes involved in determining growth and body composition.A number of these approaches have focused upon the GH axis, for example immunoneutralization of somatostatin (which normally inhibits GH secretion) to improve growth, the use of antibodies to GH which can enhance its effects in vivo and the development of antibodies which mimic the actions of GH. Although immunization against somatostatin has led to increased growth rates in a number of studies other studies have failed to demonstrate such an effect. A precise understanding of the mechanism of action of this approach is required before we can begin to understand why success is not assured. Antibodies which enhance GH action clearly do work reproducibly but the major problem in developing this approach is to produce an inexpensive peptide immunogen (its sequence derived from GH) which can be used to actively immunize animals so that their own antibodies enhance endogenous GH activity. Anti-idiotypic mimics of GH have also been produced which have GH actions in vivo but again this approach is of limited value until appropriate vaccines can be developed.A different approach to the problem of excess fat deposition involves the use of antibodies directed against the plasma membranes of adipocytes in order to elicit their destruction and thereby limit the storage capacity for fat. This technique has been demonstrated in rats, sheep and pigs in both passive and active immunization techniques. Once again, however, this promising approach is limited by the lack of a commercially suitable vaccine. The identification of individual membrane proteins which are antigenic has been achieved and this provides the prospect of producing recombinant DNA-derived vaccines.Whether these new approaches will be perceived as acceptable to the general public remains a serious concern and a potential limitation to their development as many would-be sponsors cut back their support for research in these areas.
Genetic and phenotypic relationships between conformation and production traits in Ayrshire heifers
Authors: Mrode R. A. , Swanson G. J. T. 
Published: September 2010

AbstractFirst lactation records for production traits (milk, fat and protein yields) and 17 linear type traits for 7169 Ayrshire heifers were analysed to estimate genetic parameters for type traits and to examine the relationship between type and production traits. A multivariate restricted maximum likelihood procedure fitting a sire model with sire relationships included was used for all analyses.Heritabilities for production traits were approximately 0·3 and genetic correlations among them were high (>0·84). The estimates of heritabilities for type traits were mainly low to moderate ranging from 0·04 to 0·42. Angularity (0·80), beef shape (0·49), foot angle (0·53) and stature (0·46) had higher heritabilities. Generally phenotypic correlations among type traits were lower than the genetic correlations. The highest negative genetic correlation was between rear legs side and rear legs rear (-0·95) and the highest positive correlation between chest width and beef shape (0·93).Genetic correlations between type and production were low to moderate and were similar for milk, fat and protein yields. The genetic correlations between the production traits and chest width, udder depth and beef shape were negative but were positive between production and angularity, rear udder width and teat placement side.
A comparison of alternative index procedures for multiple generation selection on non-linear profit
Authors: Groen A. F. , Meuwissen T. H. E. , Vollema A. R. , Brascamp E. W. 
Published: September 2010

AbstractAlternative index procedures for selection on non-linear profit are quadratic indices, desired gains indices, group or mate selection indices, or direct optimization of responses over multiple generations. In this study a multiple generation time horizon was considered and several linear, quadratic and desired gains indices were compared. Genetic and economic responses over multiple generations were calculated considering a quadratic profit function combining protein yield and days open.Directly optimizing reponse over multiple generations was found to yield slightly higher economic responses (+ < l.5%) than stepwise (each generation) adjustment of a linear index. A constant linear index using base population averages and a quadratic index were found to be less efficient. The quadratic index was less efficient than the linear index when considering multiple generations. Desired gains indices allowed stabilization of base population average for days open, however, forcing considerable economic losses. Relative efficiencies of methods depended on the degree of non-linearity of the profit function.
Female-female influences on the duration of the post-partum anoestrous period in beef cows
Authors: Wright I. A. , Rhind S. M. , Smith A. J. , Whyte T. K. 
Published: September 2010

AbstractTwo experiments were conducted to determine whether female to female influences could reduce the duration of the post-partum anoestrous period in beef cows. In experiment 1, cows were housed from calving, either in individual stalls, which precluded physical contact with other cows (treatment I; no. = 19) or as a group, with a cow in oestrus introduced to the group twice per week (treatment G; no. = 18). The percentage of cows cycling by day 50 post partum was similar for both treatments, but at 91 days post partum was significantly higher (P <0·05) in the G than in the I cows (89% v. 58%).In experiment 2, cows were housed in individual stalls from calving and exposed twice per week to either cervical mucus collected from cows in oestrus (treatment M; no. = 21) or distilled water (treatment W; no. = 24). The percentage of cows cycling by 70 days post partum was similar in both treatments but by 130 days there were significantly more (P <0·05) M cows cycling (86% v. 58%). In neither experiment were LH profiles at 22,43 or 64 days influenced by treatment.The results indicate that cervical mucus of cows in oestrus contains pheromone(s) which can reduce the postpartum anoestrous period in beef cows with extended anoestrous periods.
The influence of food intake and allyl trenbolone administration during lactation on plasma steroid concentrations and the reproductive performance of multiparous sows
Authors: Costa A. N. , Varley M. A. 
Published: September 2010

AbstractAn experiment was made to examine the effects of food intake and an orally active progestagen on plasma steroid concentrations and subsequent reproductive performance of multiparous sows. Thirty-five multiparous Landrace × Large White sows were assigned to one of four treatments immediately after parturition. Treatment H-AT sows were offered a high level of food intake throughout lactation: 3·5 kg of a diet containing 160 g/kg dry matter (DM) of crude protein and 13 MJ digestible energy per kg DM given twice daily. Treatment H+AT sows were offered the same food intake as H-AT sows and in addition they were given 20 mglday of allyl trenbolone (AT) mixed with the morning feed. Treatment L-AT sows were given 1·5 kg of the same diet offered twice daily during lactation and treatment L+AT sows were also offered this lower level of food intake and given AT. The respective levels of food intake were offered to sows from the 1st day of lactation onwards until weaning at 21 days post partum. Litter weights at weaning were influenced significantly by feeding level (P< 0·001) and also by AT administration (P<0·05). Sows on the high level of feeding had the heaviest litters and food-restricted sows had the lightest litters. AT treatment depressed litter weight at weaning. There was no effect of food level or AT on the plasma concentrations of progesterone or oestrogens during lactation. There was a highly significant (P<0·001) difference in mean plasma oestrogen concentration between high (H-AT and H+AT) and low (L-AT and L+AT) fed groups during early pregnancy in the subsequent cycle. Sows given a combination of high energy in lactation and AT (H+AT) exhibited shorter intervals from weaning to oestrus than both groups of food-restricted (L-AT and L+AT) sows fP<0·01) but treatment had no significant effect on either the farrowing rate or on the subsequent litter size. It is concluded that despite significant changes in the live weight and condition of sows and changes in steroid hormone concentrations due to food intake and the administration of allyl trenbolone, there were no significant effects on reproductive performance.
Selection for components of efficient lean growth rate in pigs 4. Genetic and phenotypic parameter estimates and correlated responses in performance test traits with ad-libitum feeding
Authors: Cameron N. D. , Curran M. K. 
Published: September 2010

AbstractGenetic and phenotypic parameters and correlated responses in performance test traits were estimated for populations of Large White (LW) and British Landrace (LR) pigs tested in Edinburgh and Wye respectively, to four generations of divergent selection for lean growth rate (LGA), lean food conversion (LFC) and daily food intake (DFI) with ad-libitum feeding.There were differences between the two populations in genetic parameters, as LW heritabilities for growth rate, daily food intake and backfat depths were higher and the correlation between growth rate and backfat was positive for LW, but negative for LR. However, heritabilities, genetic and phenotypic correlations were generally comparable between selection groups, within each population. Genetic and phenotypic correlations indicated that animals with high daily food intakes were faster growing, had positive residual food intakes (RFI), were fatter with higher food conversion ratios. RFI was highly correlated with daily food intake and food conversion ratio, but phenotypically independent of growth rate and backfat, as expected.Selection for LGA, in LW and LR populations, increased growth rate (54 and 101 g/day), but reduced backfat (−3·9 and −2·0 mm), food conversion ratio (−0·23 and −0·25) and total food intake (−11·8 and −12·6 kg). There was no change in daily food intake in LW pigs (−19 g/day), but daily food intake increased in the LR pigs (69 g/day). With selection for LFC in LW and LR populations, there was no response in groivth rate (9 and 9 g/day), but backfat (−4·1 and −2·1 mm), total (−6·6 and −11·8 kg) and daily food intake (−90 and −172 g) were reduced, as animals had lower food conversion ratios (−0·13 and −0·22). LW and LR pigs selected for DFI ate more food in total (6·8 and 5·9 kg) and on a daily basis (314 and 230 g), grew faster (94 and 51 g/day) and had higher food conversion ratios (0·12 and 0·13). Backfat was increased in LW pigs (3·7 mm), but not in the LR population.In general, efficiency of lean growth was improved by increasing groivth rate, with little change in daily food intake from selection for LGA, but was primarily due to reduced daily food intake with selection on LFC.
Milk production from grass silage diets: effects of the composition of supplementary concentrates
Authors: Aston K. , Thomas C. , Daley S. R. , Sutton J. D. 
Published: September 2010

AbstractThirty-six British Holstein-Friesian cows were offered 9 kg dry matter (DM) daily of one of 12 concentrates together with grass silage ad libitum in a cyclical change-over design experiment during lactation weeks 8 to 22. The carbohydrate source in the concentrates was either mainly starch, mainly digestible fibre or a 1:1 mixture. Each concentrate type was formulated to provide 120, 160, 200 or 240 g crude protein (CP) per kg DM and similar metabolizable energy concentration. Silage contained 142 g CP per kg DM, in vivo digestible organic matter was 0·690 kg/kg DM, pH 4·4 and ammonia-N 172·2 g/kg total nitrogen.Silage intake increased as fibre replaced starch in the concentrate. Apparent digestibility of organic matter and energy were highest for starch-based concentrates, but there was no effect of carbohydrate source on yields of milk and milk solids. Milk protein concentration was depressed by feeding mixed or fibrous carbohydrates.Silage intake increased on average by 0·13 kg DM per additional 10 g/kg CP in the concentrate. The digestibility of the diet was not affected by increasing CP except for nitrogen. Milk yield increased by 0·028 kg per additional g/kg CP in the concentrate and there were linear effects ofCP on yields of milk solids.As CP increased, milk fat concentration tended to rise with starch but was depressed both overall and by offering mixed or fibrous carbohydrates. In contrast milk protein concentration increased with mixed and fibrous carbohydrates but not with starch.It is concluded that when silage is given ad libitum with 9 kg/day concentrates, CP level has more effect than source of carbohydrate on milk production.
Body-weight loss, blood and rumen fluid characteristics and nitrogen retention in lambs in negative energy balance offered diets with differing glucogenic potential
Authors: Moloney A. P. , Moore W. 
Published: September 2010

AbstractThe effects of altering the glucogenic potential of the diet of wether lambs (initial body weight 56·4 kg) offered an energy allowance of 0·25 that required for maintenance on body-weight loss, nitrogen retention and blood and rumen fluid parameters were examined. Whole barley was offered alone or substituted on an isoenergetic basis with 40 or 120 g of a blend of glucose precursors (polyhydric alcohols, propylene glycol, sodium propionate) absorbed on to palm kernel meal (acetona meal), to 36 lambs (no. = 12 per treatment) for 8 weeks. Substituting barley with 40 g acetona meal had a small but non-significant effect in decreasing body-weight loss and plasma aspartate amino transferase activity and in increasing plasma insulin concentration. Increasing the glucogenic potential of the diet by substituting barley with 120 g acetona meal decreased body-weight loss in the early phase of the study, decreased plasma concentrations of non-esterified fatty acids and increased the proportion of propionate in volatile fatty acids in rumen fluid, plasma aspartate amino transferase and gamma-glutamyl transferase activities and plasma insulin concentrations. Increasing the glucogenic potential of the diet did not affect nitrogen retention or plasma glucose concentration. It is concluded that increasing the glucogenic potential of the diet of lambs resulted in an increase in metabolic efficiency at the onset of negative energy balance which was mediated through a change in plasma insulin concentration. The absence of a significant difference in body-weight loss between the diets in the latter part of the study reflects the lack of sustained ketosis.
An analysis of the variation in the lean tissue distribution of sheep
Authors: Wolf B. T. 
Published: September 2010

ABSTRACTThe distribution of lean tissue between eight standard joints was examined in 956 crossbred lambs slaughtered at constant live weights of either 35 or 40 kg. The sire breeds used were the Dorset Down, Ile-de-France, Oldenburg, Oxford, Suffolk and Texel. Sire breed did not have a significant effect on the proportion of total carcass lean found in the higher-priced joints but did show significant differences in the proportion of total carcass lean found in individual joints, with a maximum difference of 7·7 g total lean per kg joint being recorded. Similarly, small but significant effects due to ewe age (1 to 3 years), rearing type (single, twin, triplet), sex (male castrate, female) and weight of total lean were reported for the proportion of total carcass lean found in different joints.Heritability estimates ranged from 0·07 (s.e. 008) to 0·65 (s.e. 0·16) for the proportion of total lean in the best-end neck and higher-priced joints respectively. Phenotypic standard deviations of 5·8g/kg and 17·9g/kg were reported for the proportion of total lean found in the best-end neck and the higher-priced joints respectively. The genetic correlations between the proportion of total lean in each of the higher-priced joints and the proportion of total lean in the higher-priced joints combined were positive. A genetic correlation of 017 (s.e. 0·20) was found for the relationship between average daily gain from birth to slaughter and the proportion of total lean in the higher-priced joints.
The influence of breeding management efficiency on dairy herd performance
Authors: Bailie J. H. 
Published: September 2010

ABSTRACTComputer simulation was used to measure the effects of breeding management efficiency in block calving dairy herds and in those with a long mating season of 9 months. In particular, the effects of varying levels of oestrus detection and conception rates were assessed, and the product of these two parameters defined as the fertility factor. As the fertility factor increases from 20 to 50, where the mating season extends to 9 months, the mean calving index for the herd decreased linearly from 393·5 to 373·6 days and the culling rate for failure to conceive declines in curvilinear fashion from 0·196 to 0·006. Concurrent with the decrease in calving index, mean annual milk yield and margin over purchased food increase, with the herd commencing calving in January showing a more marked response than the herd commencing calving in October. When overall replacement rate is also taken into account, the margin over purchased food net of herd depreciation per cow, at 1979/80 prices, changes from £270·7 to £315·2 in the January herd compared with £275·9 to £315·8 in the October herd. For each day change in calving index associated with alteration in fertility factor, there is a change of £2·24 for the January herd and £2·01 for the October herd in margin over purchased food net of herd depreciation.In the block calving herd, increases in fertility factor are reflected mainly in changes in culling rate for failure to conceive from 0·292 to 0·033, and not in margin over purchased food.
A note on the estimationin vivoof body fat in cows using deuterium oxide or adipose-cell size
Authors: Robelin J. 
Published: September 2010

ABSTRACTTwo methods of estimating body fatin vivoin cattle, namely measurement of body water by dilution of deuterium oxide and subcutaneous adipose-cell size, were studied in mature cows and compared with a classical method based on dissection of a sample joint.Total body fat, measured after complete dissection of 12 dry cows, varied between 64 and 185g/kg body weight. Rib fat and adipose-cell diameter were related positively, while body water was related negatively to total body fat. The equations for prediction of total body fat were sufficiently accurate (s.d. = 10·1 to 11·5 g total body fat per kg body weight) to warrant further examination, and adipose-cell diameter was as accurate as body water.
The influence of nutrition in early life on growth and development of the pig 2. Effects of rearing method and feeding level on growth and development to 75 kg
Authors: Campbell R. G. , Dunkin A. C. 
Published: September 2010

ABSTRACT1. Fifty-seven piglets were used to study the effects of rearing pigs on the sow or artificially on a low or high level of feeding between 1·8 and 6·5 kg live weight and either a low or high level of feeding between 6·5 and 20 kg live weight on growth and development to 75 kg live weight.2. The artificially reared pigs fed at the higher level grew more rapidly (P < 0·05) and were fatter (P < 0·05) at 6·5 kg live weight than their more restrictedly fed counterparts. The pigs reared on the sow grew at the same rate as the artificially reared pigs fed at the low level but at 6·5 kg live weight were as fat as the artificially reared pigs fed at the higher level.3. Between 6·5 and 20 kg live weight the artificially reared pigs previously fed at the lower level grew more rapidly (P < 0·05) than their more liberally fed counterparts which in turn, grew at a faster rate (P < 0·05) than pigs previously reared on the sow. However, nutrition prior to 6·5 kg live weight had no influence on performance or body composition subsequent to 20 kg live weight.4. Raising the level of feeding between 6·5 and 20 kg live weight increased growth rate (P < 0·05) and body fat content at the latter weight (P < 0·05). However, subsequent to 20 kg live weight, the pigs previously fed at the lower level exhibited more rapid and efficient growth (P < 0·05) and at 75 kg live weight were leaner (P < 0·05) than those fed more generously between 6·5 and 20 kg.5. At 6·5 kg live weight the pigs reared on the sow contained less deoxyribonucleic acid (P < 0·05) in the m. adductor than pigs from either of the two artificially reared groups. Muscle deoxyribonucleic acid at 20 and 75 kg live weight was unaffected by nutrition before 6·5 kg live weight or level of feeding between 6·5 and 20 kg live weight.