bluuebunny/crossref_metadata_2025 huggingface dataset:
The responses of growing pigs to dietary lysine, as free lysine hydrochloride or in soya-bean meal, and the influence of food intake
Authors: Fuller M. F. , Wood J. , Brewer A. C. , Pennie K. , MacWilliam R.
Published: September 2010

One hundred and ninety-two individually fed pigs, half of them castrated males and half females, were used to examine the effects of reducing the concentration of dietary lysine below the value of 0·84 g/MJ digestible energy suggested by the Agricultural Research Council (1981). Lysine was varied by altering the inclusion of either free lysine hydrochloride or soya-bean meal. Over the whole experiment from 18 to 65 kg live weight, there were significant reductions in live-weight gain and increases in food: gain ratio in response to reducing lysine concentration; these changes were greater with soya-bean meal than with free lysine. During later growth (45 to 65 kg) alterations in lysine concentration had no significant effect.

For pigs given soya-bean supplements, both the live weights after fasting and the carcass weights were significantly lower than for those given free lysine hydrochloride, suggesting that at least part of the difference in growth between pigs given free lysine hydrochloride and soya-bean was attributable to this difference. The food required per kg carcass weight gain, or per kg lean tissue gain, was not affected by the source of lysine.

In a subsidiary experiment using nitrogen balance, supplements of five amino acids in addition to lysine did not increase nitrogen retention, providing further evidence that lysine was the only amino acid responsible for the response seen with soya-bean meal. It was concluded that for growing pigs with daily food intakes of 1·5 to 1·8 kg, a lysine concentration of at least 0·81 g/MJ digestible energy is required to maximize performance.
The effects of fat thickness and sex on pig meat quality with special reference to the problems associated with overleanness 1. Butcher and consumer panel results
Authors: Kempster A. J. , Dilworth A. W. , Evans D. G. , Fisher K. D.
Published: September 2010

A trial was carried out to examine some of the factors involved in the possible deterioration in pig meat quality associated with the trend towards leaner carcasses. Five batches of pigs, each one as far as possible from the same producer, were identified at each of 10 abattoirs. Three gilts and three entire males were selected from each batch to show a range of fatness. Overall mean fat thickness measurements over the m, longissimus at the last rib (P2, mm) for lean, average and fat carcasses were 8·8, 11·6, and 16·9 (gilts) and 8·4, 11·7 and 15·5 (entire males). The overall mean carcass weight was 58 kg. Loin and leg joints were assessed for cutting and presentational characteristics by a panel of 45 butchers. Loin chops and shoulder and leg joints were assessed for eating characteristics by consumer panels involving a total of 500 families. Butchers judged the fat of lean carcasses to be softer and the meat to be floppier and with more tissue separation. Entire males also had slight disadvantages in these respects. Consumers found the chops of lean carcasses to be less juicy on average (0·16 lean carcasses were judged to have dry chops compared with 0·09 for fat carcasses) with a tendency towards toughness and less flavour. There were no differences in overall acceptability. Meat from the two sexes did not differ in eating quality or overall acceptability to consumers. The butchers were more critical of overlean carcasses than were consumers. The trial indicates that the trend towards leaner carcasses is likely to create butchery problems but not consumer dissatisfaction.
A note on the use of pressed sugar-beet pulp in the diet of lactating dairy cows
Authors: Murphy J. J.
Published: September 2010

A Number of experiments Bhattacharya and Sleiman, 1971; Bhattacharya and Lubbadah, 1971; Castle, 1972; Castle, Gill and Watson, 1981) have shown that dried sugar-beet pulp is equal to barley in feeding value when included in the concentrate portion of the diet given to milking dairy cows. In recent years, there has been increasing interest in feeding the undried pulp, from which some of the moisture has been removed by heavy presses. This product is known as ‘pressed pulp’.
Relative growth of incisor arcade breadth and eating rate in cattle and sheep
Authors: Taylor C. S. , Murray J. I. , Illius A. W.
Published: September 2010

Maximum eating rate, rmaxin kj metabolizable energy per min, at a given body weight W kg, can be predicted in normally growing cattle when adult body weight, A kg, is known, by the formula of Taylor and Murray (1987) as rmax= 31μ0·86A0·73whereu= W/A is degree of maturity in body weight. When the pattern of normal growth is disturbed by fluctuating levels of food intake, a better prediction can be obtained in terms of incisor arcade breadth. This paper gives the allometric relationship between degree of maturity in body weight,u, and degree of maturity in incisor arcade breadth uD, fo r both cattle and sheep, asuD=u0·29.

Combining this allometric relationship with that of Illius and Gordon (1987) gives the following formula for incisor arcade breadth, Du(mm), in the rth species at age,t, in relation to degree of maturity in body weight,uit, and adult body weight,Aikg): Dit= 7·8 uit0·29Ai0·36. Substituting uDand adult arcade breadth, Dadult, foruand A in the formula of Taylor and Murray (1987) gives the following more robust formula for predicting maximum eating rate, namely, rmax= 0·53u3DD2adut.
Mineral retentions and body composition of grazing lambs
Authors: Thompson J. K. , Gelman A. L. , Weddell J. R.
Published: September 2010

Growth rates and chemical compositions were measured with ram lambs grazing pure stands of perennial ryegrass, timothy, cocksfoot and tall fescue. A group of lambs slaughtered at the start of the trial enabled estimates to be made of the live-weight gains over the summer and the composition of these gains. The composition of the grass was also measured in samples taken at weekly intervals and estimates were made of the nutrients consumed from the different grass plots.

The quantities of ash, Ca, P and Mg in the empty bodies of the lambs were within the range of published values from similar studies. They support the contention that grass-fed lambs tend to have larger contents of ash, Ca and P in their empty bodies than concentrate-fed lambs of similar weight. Perennial ryegrass provided a superior diet in that lambs eating this grass grew more quickly, with leaner tissues and higher levels of ash, Ca and P in their empty-body gains. Lambs consuming tall fescue grew most slowly but their mineral contents were as large as the ryegrass-fed lambs when data were adjusted for differences in empty-body weight. Lambs fed on timothy or cocksfoot were the most poorly mineralized in spite of consuming considerably more Ca, P and Mg than the lambs on ryegrass. The data suggest that the efficiencies of absorption of Ca and P in ryegrass may be high, at about 0·64 for Ca and 0·71 for P.
Effect of unwilted and wilted grass silage on the intake and performance of pregnant ewes at varying levels of concentrate feeding
Authors: Wilkinson S. C. , Chestnutt D. M. B.
Published: September 2010

In three separate experiments a total of 144 Greyface ewes was offered direct-cut or wilted silage from week 4 to 5 of pregnancy until lambing with varying levels of concentrate during the last 6 weeks of pregnancy. Wilting resulted in a proportional increase in the intake of silage dry matter of 0·08 on average but, because digestibility of the wilted silages was lower, digestible energy intake of both silages was similar. Average change in ewe live weight from housing until after lambing was not affected by silage type and there was a small, non-significant increase in lamb birth weight on direct-cut silage. There was no evidence of any reduction in silage intake as total concentrate intake over the last 6 weeks of pregnancy increased to about 18 kg, and limited evidence of a reduction at higher levels with some indication of a greater reduction on direct-cut than on wilted silage. Compared with no-concentrate feeding the highest level increased ewe live weight by 252 g/kg concentrate and there was a non-significant effect on lamb birth weight of 13 g/kg concentrate.
Inbreeding and family index selection for prolificacy in pigs
Authors: Toro M. A. , Silio L. , Rodrigañez J. , Dobao M. Teresa
Published: September 2010

The use of family selection indices has been proposed as a promising selection method for increasing prolificacy in pigs. Responses of up to 0-50 pigs per litter per generation are predicted from selection programmes using information from the dam and from relatives (full and half-sibs) of the dam and sire. In order to test this method in populations of finite size, the rates of selection response and the accumulation of inbreeding have been studied by simulation along 10 generations in a selected herd of 10 sires and 100 dams using five different family selection indices (Id, Ifd, Ihd, Ifs, Ihs). Two undesirable features were evident: (a) the standard deviations of indices were lower than those expected; and (b) the increase of inbreeding was up to three times that expected without selection. Both effects increased with the complexity of the family index reducing the rates of selection responses per generation, when a genetic model with dominance was assumed, to values close to 0·20 piglets, similar to those obtained with the basic index (Id). Some results of inbreeding effects on reproductive traits in three strains of an old closed herd of Iberian pigs are also presented. Multiple regression analysis of data from 4657 litters indicated a decrease in the number of live born ranging from 0·14 to 0·35 piglets per 10% increase in dam or litter inbreeding coefficient.
The influence of dietary protein intake and of hoof trimming on lameness in dairy cattle
Authors: Manson F. J. , Leaver J. D.
Published: September 2010

In an experiment during weeks 3 to 26 of lactation, two groups of 12 cows were offered a mixed concentrate/grass silage diet containing 161 g crude protein per kg dry matter, and two similar groups a diet containing 198 g crude protein per kg dry matter. The concentrate: forage ratios and the daily metabolizable energy intakes were the same for all four groups. The cows in one of the two groups at each crude protein level had their hooves trimmed prior to parturition, the other group remaining untrimmed. The high protein diet significantly increased locomotion score (higher scores indicate poorer locomotion), the number and duration of clinical cases of lameness and outer toe length. Trimming of hooves reduced locomotion scores and the number and duration of clinical cases. Hoof growth was significantly increased by trimming. Mid-sole hardness was negatively correlated with locomotion score. At the two extremes, the low protein trimmed group had five cows lame for an average of 1·0 weeks, whereas the high protein untrimmed group had nine cows lame for an average of 4-2 weeks. Condition score and live-weight change were negatively correlated with locomotion score. There were no significant differences between treatments in milk solids yield.
The effect of oestrogenic agents on live-weight gain, carcass composition, reproductive function and tissue residues in intensively reared beef bulls given cereal-based diets
Authors: Peters A. R. , Southgate J. R. , Aughey E. , Dixon S. N.
Published: September 2010

The use of oestradiol-17β was evaluated in cereal-based beef production on 14 farms with 450 bulls. Half of the bulls were implanted subcutaneously in the ear with a silastic rubber implant containing 45 mg oestradiol-17β Representative bulls close to mean weight for each group were selected for slaughter on the same day at the end of the trial for carcass measurements. The remaining bulls were slaughtered at the farmers' discretion. Where possible, slaughter live weight (208 bulls), carcass weight (412) and European Economic Community carcass classification (353) were recorded. Implanted bulls had higher gains only in the first 3 months (+76 (s.e. 17) g/day;P< 0·001) and had heavier carcasses with the extra weight in the forequarter (+2·3 (s.e. 0·61) kg;P< 0·001), better carcass shape (+0·9 (s.e. 0·3) points;P< 0·01) and more subcutaneous fat in the thin flank (+1·3 (s.e. 0·6) g/kg;P< 0·05). Implanted bulls selected for slaughter by farmers were not slaughtered earlier, but killed out better (+0·7 (s.e. 0·3) g/kg;P< 0·05) and had heavier carcasses (+4·6 (s.e. 0·5) kg;P< 0·01) of better shape (+0·8 (s.e. 0·3) points;P< 0·05).

The use of zeranol was evaluated in cereal beef production on 15 farms with 385 bulls. Half received 36 mg zeranol which was repeated after 6 months. Forty-four bulls were selected for detailed carcass assessment as above. Implanted bulls had daily gains 0·06 (s.e. 0·01) kg greater (P< 0·001) than controls. Farmers chose to slaughter implanted bulls 8·3 (s.e. 3·8) days earlier (P< 0·05) at only marginally heavier weights (+4·8 (s.e. 3·1) kg;P= 0·08). More implanted bull carcasses were distributed in better shape and higher fat classes (P< 0·01). There were no significant differences in fore- and hindquarter and thin-flank tissue proportions. Oestradiol treatment marginally decreased testis weight in slaughtered bulls whereas zeranol treatment had no significant effect although epididymal weight was decreased in zeranol treated bulls. There were no clear effects of either treatment on testicular structure, but both oestradiol and zeranol caused a degree of disruption to the epididymal epithelium. Zeranol concentrations in treated animal tissues were not significantly different from those in control animals.
Endogenous hormone and metabolite concentrations in different breeds of beef steer on two systems of production
Authors: Beeby J. M. , Haresign W. , Swan H.
Published: September 2010

The experiments were conducted to investigate the effect of sire breed and production system on serum GH, insulin, prolactin, glucose and blood urea nitrogen concentrations in growing beef cattle. A total of 187 steers, representing a wide range of maturity types, was reared to slaughter on either the 16-month or 24-month production systems in experiment 1, and blood samples for hormone and metabolite determinations were collected at 3-monthly intervals. Experiment 2 compared only the extremes of maturity type, with four early- and four late-maturing animals on each production system. Blood samples from these animals were collected hourly for 10 h on 2 or more consecutive days at six different time periods during the growth of the animals.

Although significant between-breed differences in hormone concentrations were observed in experiment 1, there were no significant correlations between growth rate and circulating hormone concentrations. These results were largely borne out by the more detailed blood sampling used in experiment 2.

Differences did occur in live-weight gain, GH and insulin concentrations between production systems, although these were largely determined by the induced changes resulting from the imposition of a store period on the animals produced through the 24-month production system.

These results indicate that between-breed differences in growth rate cannot be accounted for by differences in circulating GH, insulin and prolactin concentrations. Rather, it appears that the hormones are primarily used to enable the animal to adjust its metabolism to changes in nutrient supply.
Genetic variations in subcutaneous adipose tissue metabolism in sheep
Authors: Sinnett-Smith P. A. , Woolliams J. A.
Published: September 2010

Adipocyte volume rates of fatty acid synthesis, acylglycerol glycerol synthesis and lipolysis (basal and noradrenaline stimulated) along with the activities of acetyl CoA carboxylase and lipoprotein lipase were determined in subcutaneous adipose tissue, sampled by biopsy, from the rump of four breeds of sheep differing in growth and body characteristics.

Significant differences among breeds were observed for adipocyte volume, fatty acid synthesis, stimulated lipolysis rates, initial and total acetyl CoA carboxylase activity and lipoprotein lipase activity, but not for acylglycerol glycerol synthesis.

Differences in adipocyte volume did not appear to be related to the previously reported carcass fatnesses of the breeds. Similarly differences in adipocyte volume were not related to differences in either de novo fatty acid synthesis or lipolysis rates. Across breeds there was a trend toward higher acylglycerol glycerol synthesis rates associated with greater adipocyte volume although the source of fatty acids for esterification varied greatly.

Breed variation in fatness in sheep therefore appears to be a consequence of different balances of anabolic and catabolic processes in adipose tissue, with a unique pattern for each breed. Further elucidation of these patterns may lead to the identification of key sites for genetic manipulation. In addition these breed differences provide an alternative, complementary and qualitatively different, model for the study of the control of fat metabolism to that provided by nutritional or hormonal manipulations.
Effect of average carcass fat concentration on correlations among lamb carcass measurements
Authors: Bennett G. L. , Meyer H. H. , Kirton A. H.
Published: September 2010

The effects of average carcass fat concentration of a group of lambs on correlations among lamb carcass measurements within the group and of slaughter age on variances of carcass measurements were studied. Three-hundred and sixty-eight crossbred lambs from one experiment were slaughtered on 10 days over a 2-year period. Average carcass fat concentration of the 10 groups ranged from 179 to 326 g/kg carcass weight. Variances of carcass fat, water and protein concentrations and of muscle measurements did not increase at later slaughter ages but variances of kidney fat weight, fat depths and total tissue depths increased. Several correlations among carcass measurements had significant regressions on average carcass fat composition of the groups slaughtered. When measurements were adjusted for age but not weight, correlations of carcass weight, kidney fat weight, specific gravity, tibia and tarsus length and m. longissimus depth with carcass fat, water and protein concentrations weakened as carcass fat concentration of the group increased. Correlations of kidney fat, specific gravity and m. longissimus width with fat, water and protein concentrations adjusted for carcass weight weakened as average carcass fat concentration of the group increased. Multiple regression equations did not reveal any advantage in using combinations of muscle or leg dimensions to predict fat concentration.
Rumen degradation of straw 5. Botanical fractions and degradability of different varieties of oat and wheat straws
Authors: Shand W. J. , Ørskov E. R. , Morrice L. A. F.
Published: September 2010

Straw from six varieties of oat and 12 varieties of wheat were divided into their botanical fractions of leaf plus leaf sheath, internodes, nodes and chaff, and the rumen degradabilities of the individual fractions determined by the nylon bag method.

The proportions of the fractions varied between varieties, but more so within wheat than within oat straw. The proportion of leaf plus leaf sheath varied from 0·27 to 0·37 for wheat and 0·29 to 0·33 for oats with the proportion of stem ranging from 0·41 to 0·51 for wheat and from 0·55 to 0·60 for oats. There were also differences in degradation characteristics, more evident in wheat than in oats. The 48-h degradability varied from 570 to 650 g/kg for wheat leaf plus leaf sheath and from 300 to 380 g/kg for wheat stem. The respective ranges for oat straws were from 480 to 530 and from 250 to 280.

Generally, the wheat straw varieties, and in particular leaf from wheat straw, were of a higher degradability than oat straw. The mean 48-h degradabilities of wheat and oat leaf were 615 and 501 g/kg respectively. There was no relationship between the nitrogen content of leaves or stems and their degradability.
Effect of level of food intake in mid and late pregnancy on the performance of breeding ewes
Authors: Wilkinson S. C. , Chestnutt D. M. B.
Published: September 2010

In three experiments pregnant ewes (mean weight 72·5 kg) were subjected to different planes of nutrition on grass silage-based diets during mid pregnancy and, in factorial designed trials with ad libitum silage or ad libitum silage + concentrates in late pregnancy. The high plane of mid-pregnancy nutrition resulted in an average gain of 11·5 kg between weeks 7 and 14 of pregnancy while the low plane gave an average loss of 3·5 kg during this period. These differences did not affect lamb birth weight but ewes on the high plane were 7·2 kg heavier after lambing than those on the low plane. The effect of plane of nutrition during mid pregnancy on silage intake during late pregnancy was variable but there was some evidence of a greater reduction in intake during the last few weeks of pregnancy following the high plane of mid-pregnancy nutrition. The higher plane of nutrition in late pregnancy resulted in higher ewe live weights as well as higher lamb birth weights and highest lamb birth weights occurred following restriction in mid pregnancy and a high plane of nutrition in late pregnancy.

Plasma 3-hydroxybutyrate levels were variable but there was little evidence of an effect of mid-pregnancy nutrition although levels appeared to be increased by the low plane of nutrition in late pregnancy.
Rumen degradation of straw 6. Effect of polysaccharidase enzymes on degradation characteristics of ensiled rice straw
Authors: Nakashima Y. , Ørskov E. R. , Hotten P. M. , Ambo K. , Takase Y
Published: September 2010

The effects of three variables; polysaccharidase inclusion level (0, 5 and 10 g/kg), moisture content (500, 600 and 700 g/kg dry matter (DM), and particle size (20, 5 and 2 mm), on the quality and degradation characteristics of ensiled rice straw were investigated. The polysaccharidase product used was shown to contain a broad spectrum of activities against polysaccharides typical of plant material. The major activities present being: mixed link glucanase, xylanase and both endo- and exo-cellulase. The straw treated with polysaccharidase had a lower final pH (5·21, 4·87, 4·82;P< 0·01), higher concentrations of lactic acid (1·98, 3·90, 3·67 g/kg;P< 0·01), a lower content of neutral-detergent fibre (689, 630, 621 g/kg DM;P< 0·01) and a higher solubility, measured as washing losses from nylon bags (152, 196, 212 g/kg DM;P< 0·01) for the 0, 5 and 10 g/kg polysaccharidase treatments respectively. The samples were subsequently incubated in nylon bags in the rumen of three sheep for 8, 16, 24, 48 and 72 h to estimate degradation rate and potential degradability using the expression p = a + b (1 – e−ct) wherepis degradability at timetanda, bandcare constants. While there was no effect of moisture content or physical form of the straw, the degradation rate constant (c) was increased (P< 0·01) by the addition of polysaccharidase. The maximum potential degradability (a + b), however, was not altered by any of the treatments. The values forcwere 0·0498, 0·0677 and 0·0817 per h and for (a + b) were 62·4, 62·1 and 62·8 g/100 g DM for the 0, 5 and 10 g/kg polysaccharidase enzyme additions respectively. It is concluded that the use of polysaccharidase enzymes can assist in the preservation of wet straw and can result in improved degradation characteristics.
Effects of fodder beet on rumen metabolism
Authors: Sabri M. S. , Offer N. W. , Roberts D. J.
Published: September 2010

Two experiments were carried out with sheep, to characterize fodder beet in terms of its effects on rumen function. In experiment A, a study was made of the effects of supplementing hay with fodder beet (FB) on rumen pH and volatile fatty acid (VFA) concentration compared with two control supplements of either barley/maize (BM) or molassed sugar-beet shreds (SBP). Hay was offered with all three supplements in a 50: 50 ratio on a dry matter (DM) basis. The mean rumen pH for the fodder beet diet was 6·34 and intermediate between two controls (BM 6·20 and SBP 6·38). There was no significant difference in rumen concentration of total VFA for the three different diets (FB, SBP and BM) but there were highly significant effects due to diet for acetic and propionic acid molar proportions (P< 0·001). Molar proportion of propionic acid for diets FB, BM and SBP were 0·2064, 0·2221 and 01880 respectively. The loss of DM from nylon bags incubated in the rumen of sheep given the test diets was 471, 447 and 486 g/kg for FB, BM and SBP respectively. In experiment B, the rate ofin saccoorganic matter (OM) disappearance of the three supplements were compared in sheep given a constant high forage diet (900 g/day hay DM + 200 g/day compound food DM). There were highly significant differences in rates of OM disappearances for the supplements (P< 0·001). The losses of OM measured after 3 h incubation in the rumen were 767, 608, 378 and 236 g/kg for fodder beet, barley/maize, molassed sugar-beet shreds and hay respectively.
Sucking behaviour and serum immunoglobulin levels in neonatal piglets
Authors: de Passillé Anne Marie B. , Rushen J. , Pelletier G.
Published: September 2010

The relationships between the sucking behaviour of newborn piglets during bouts of sucking and their serum immunoglobulin G (IgG) levels at 12 h of age were investigated in 274 Landrace × Yorkshire piglets from 24 second parity Yorkshire sows. Mean IgG level differed between litters but was not related to the number of live-born piglets or the mean birth weight of the litter; in addition, the amount of variation in IgG level within a litter was not related to the number of live-born piglets or the amount of variation in birth weight of the piglets.

Within a litter, lower serum IgG levels were found in piglets of birth orders greater than eight and piglets that had a very low frequency of sucking bouts. The piglets that had the higher IgG levels within a litter were those that started to suck sooner, sucked from many teats and won more of their teat disputes. Piglets that were involved in fewer teat disputes within a litter or took a greater proportion of their sucking bouts on anterior teats did not have higher IgG levels. Piglets that died differed from their surviving litter-mates in having lower IgG levels and having lost weight during the first 12 h after birth. Within a litter, IgG levels were not related to 10-day weight gain. However, litters with a lower mean IgG level also had a lower mean 10-day weight gain. It is suggested that a low mean IgG level in a litter reflects or predicts a low milk production by that sow.
Threonine supplementation of diets for pigs between 7 and 56 days of age
Authors: Leibholz Jane
Published: September 2010

Fifty entire male pigs between 7 and 28 days and 50 entire male pigs between 28 and 56 days of age' were given basal diets containing peanut meal as the protein supplement. These diets contained 4·5 to 6·1 g threonine per kg and were supplemented with graded additions of synthetic L-threonine.

It was found that the amount of threonine required for maximum performance and nitrogen retention was 6·6 g/kg dry matter (DM) between 7 and 28 days of age and 5·4 g/kg DM between 28 and 56 days of age. These values were calculated to correspond to 0·43 and 0·36 g threonine per MJ digestible energy.

The concentration of threonine in the blood plasma did not give a clear indication of the threonine requirement of the pigs.
Energy and protein utilization of lucerne hay and barley grain by yearling camel calves
Authors: Bhattacharya A. N. , Al-Mutairi S. , Hashimi A. , Economides S.
Published: September 2010

Two trials were conducted with eight yearling camels with an average intial body weight of 300 kg, to evaluate protein and energy values of lucerne hay and barley grains. In each trial, eight animals were randomly allotted to two different dietary treatments of coarsely ground lucerne hay or lucerne hay + barley grain (50:50) in such a way that two animals in each of the two blocks received the same ration. Each trial consisted of a 10-day preliminary period followed by a 7-day collection period during which total urine and faeces collections were made, and samples were processed and composited for later analysis.

All animals consumed daily an average of about 5 kg food divided in two equal meals. The apparent digestibility coefficients for organic matter, crude protein, neutral-detergent fibre and cellulose of the lucerne hay ration improved respectively from 0·615, 0·662, 0·455 and 0·555 to 0·736, 0·655, 0·547 and 0·589, as a result of incorporating 500 g/kg barley grain in place of hay in the diet. Even though there was no difference in the proportion of nitrogen retained relative to intake, the proportion of nitrogen retained relative to that absorbed was higher (P < 0·05) in the lucerne + barley group (0·769) than in the lucerne-only group (0·747). On a dry-matter basis, the feeding value in camels of digestible protein (g/kg), total digestible nutrients (g/kg), digestible energy (MJ/kg), metabolizable energy (MJ/kg), net energy maintenance (MJ/kg), net energy lactation (MJ/kg) and net energy gain (MJ/kg) were respectively 118, 552, 10·0, 8·4, 5·4, 5·0 and 2·1 for lucerne hay and 80, 800, 14·6, 12·1, 8·4, 8·8 and 5·0 for barley grain (calculated by difference).
Effects of fish-meal supplementation on performance of overfat lambs fed on barley straw to reduce carcass fatness
Authors: Vipond J. E. , King Margaret E. , Ørskov E. R. , Wetherill G. Z.
Published: September 2010

The effect of undegradable protein supply was studied in overfat lambs given low-energy diets to reduce carcass fatness. Two trials involving sequential batches of 48 overfat Suffolk × lambs investigated the effects of supplementing an ad libitum straw diet with either 0 or 100 g fish-meal pellets daily for 14-, 28- and 42-day periods. Lambs supplemented with fish meal in trials 1 and 2 lost significantly less weight. Weight losses (g/day) were - 2 v. -129 (s.e.d. 26) and -5 8 v. -188 (s.e.d. 29) respectively. There were highly significant and favourable effects of fish-meal supplementation on carcass weight and composition (recorded in the second trial only). Carcass weight (kg) after 14, 28 and 42 days was 21·8, 20·4 and 18·3 for unsupplemented lambs and 22·4, 21·9 and 21·6 for supplemented lambs; saleable lean (kg) as determined by a commercial boning-out process was 12·1, 11·3 and 10·0 v. 12·7, 12·6 and 12·3 respectively. There were corresponding changes in conformation but fat trimmed off the carcass was not significantly reduced by the dietary treatments. There was, however, a reduction by one-fifth in excess carcass fat (about 0·5 kg) over the period 14 to 42 days on trial, and over the trial as a whole, fat trim fell from an estimated proportion of carcass weight of 0·17 to 012, equivalent to a fall in Meat and Livestock Commission fatness score from 4H to 3L. Results indicated very favourable financial rewards for supplementing diets of overfat lambs with fish meal.
Path analysis and robust prediction of lamb carcass composition
Authors: Bennett G. L.
Published: September 2010

Path analysis was applied to correlations among lamb carcass measurements. Correlations were obtained from lamb carcasses averaging 15·7 kg and 270 g fat per kg carcass weight. Correlations were adjusted to represent within breed, sex and management group relationships. The purpose of the analysis was to study the relationships of carcass weight with carcass measurements and to identify carcass measurements that are independent other than through their relationships with carcass chemical fat concentration and carcass weight. The direct effect of live weight on all carcass measurements was positive. Thus, heavier carcasses with the same fat concentration had larger fat and tissue depths, muscle measurements, leg measurements and kidney fat weights. The results of correlations among the residuals suggest that fat depths C and J, specific gravity, muscle width A and kidney fat weight are nearly independent estimates of carcass composition in the sense that they are only correlated through their relationships with carcass weight and carcass fat composition. Robust predictors of carcass composition were developed by first adjusting carcass measurements for the direct effects of carcass weight and then computing regressions on the adjusted measurements. These predictors appeared to be better predictors of environmental and genetic differences than least-squares multiple regression yet reduced the accuracy of within group prediction only slightly.
Effect of restricted food intake, before and/or after mating, on the reproductive performance of Greyface ewes
Authors: Rhind S. M. , McKelvey W. A. C. , McMillen S. , Gunn R. G. , Eiston D. A.
Published: September 2010

The effect on the reproductive performance of Greyface (Border Leicester × Scottish Blackface) ewes of a low level food intake and associated loss of live weight from either 14 days before mating, or from the time of mating, until 11 to 26 days after mating, was investigated. Ewes (252) were allocated to one of three treatments with ewes within each treatment divided into two flocks (flock A: 16 ewes per treatment; flock B: 68 ewes per treatment). Ewes of treatment LL were given a ration providing proportionately 0·5 estimated metabolizable energy (ME) requirements for maintenance from 2 weeks before mating. Those of treatment HL were given a daily ration providing 1·5 estimated ME requirements for maintenance until mating and the restricted ration thereafter. Ewes of treatment HH were given the higher ration throughout the experimental period. Flock A ewes were slaughtered at 11 days post mating and flock B ewes at between 18 and 26 days post mating. Treatment differences in the ovulation rates of flock A ewes were not statistically significant but in flock B, ewes of treatment LL had a lower mean ovulation rate (1·81) than those of treatments HL (2·23) and HH (2·09) (P < 0·001). The lower ovulation rate of LL ewes relative to HL ewes in flock B was reflected in a lower mean potential lambing rate per ewe pregnant than in the HL treatment (1·58 v. 1·79; P < 0·01) and per ewe put to the ram (1·37 v. 1·65; P < 0·01). HL ewes had a slightly lower mean potential lambing rate per ewe pregnant (1·79 v. 1·97; P < 01) and per ewe put to the ram (1·65 v. 1·82; P < 0·05) than HH ewes. Ova wastage rates of LL + HL and HH ewes were 0·26 and 014 (P < 001) respectively at 24 days post mating. Values for LL and HL ewes (0·27 and 0·25 respectively) were not significantly different.

Estimated mean conceptus lengths were 370, 500 and 1400 μin for LL, HL and HH ewes respectively (P < 0·05).

It is concluded that low food intake before mating reduced the mean ovulation rate and low intakes after mating compromised embryo growth rate and induced a higher rate of ova wastage; this increase in the incidence of ova wastage was not significantly exacerbated by the low levels of intake prior to mating.
Digestibilities of nitrogen and amino acids in soya-bean, sunflower, meat and rapeseed meals measured with pigs and poultry
Authors: Green S. , Kiener T.
Published: September 2010

In order to determine the relative digestibilities of nitrogen and amino acids in foodstuffs for pigs and poultry, and the effects of manufacturing methods, equal quantities of soya-bean meal, sunflower meals [hulled (sunflower meal 1) and dehulled (sunflower meal 2)], meat meals [made with (meat meal 1), and without (meat meal 2), blood added at 250 g/kg meat tissue (wet weights)] and rapeseed meals [seeds heated at 80°C (rapeseed meal 1) or 100°C (rapeseed meal 2)] were mixed with protein-free ingredients. The diets were given to five growing pigs with ileo-rectal anastomoses, and, by crop-intubation, to 12 caecectomized and 12 intact cocks. Excreta were collected over 48-h periods. Endogenous excretion was estimated by giving protein-free diets.

In the order, soya-bean meal, sunflower meals 1, and 2, meat meals 1, and 2, rapeseed meals 1, and 2, true digestibilities were: with pigs, of nitrogen, 0·81, 0·80, 0·79, 0·64, 0·79, 0·73, 0·70 (s.e.d. 0·030), of lysine, 0·84, 0·83, 0·84, 0·65, 0·84, 0·76, 0·72 (s.e.d. 0·032); with caecectomized birds, of nitrogen, 0·92, 0·91, 0·91, 0·66, 0·78, 0·74, 0·75 (s.e.d. 0·018), of lysine 0·92, 0·91, 0·93, 0·62, 0·79, 0·70, 0·70 (s.e.d. 0·020); with intact birds, values were similar to those with caecectomized birds for soya-bean, and the sunflower meals, but lesser for meat meals 1 and 2; the solubilities of nitrogen in pepsin were 0·96, 0·92, 0·93, 0·80, 0·89, 0·87, 0·87.

Two hundred and eighty pigs (initial live weights 10 kg) were used to compare growth response to free lysine with that to lysine in soya-bean meal and sunflower meal 2. Lysine availabilities, assessed by analyses of regressions of live-weight gain against lysine intake were 0·82 (s.e. 0·12) for soya-bean meal, and 0·82 (s.e. 0·18) for sunflower meal 2.

Amino acid digestibilities of the sunflower meals were similar to those of soya-bean meal, and were not influenced by dehulling; values for the rapeseed meals were lower, and unaffected by differences in heating severity; values for the meat meal were reduced by blood addition. Values differed between pigs and poultry, but there was consistency in the extent to which each species discriminated between some foodstuffs. The pepsin test was insensitive. The large standard errors associated with availability values prevented meaningful comparisons with digestibility values.
A method to incorporate competitive position in the breeding goal
Authors: de Vries A. G.
Published: September 2010

The value of the improvement of a trait for a breeding organization is determined by its impact on the saleability of its breeding stock. This impact is influenced by the competitive position of the breeding organization, i.e. by the performance of its breeding stock relative to other breeding organizations. A method was developed to take effects of competitive position on the breeding goal into account in designing selection indexes. The main conclusions were as follows.

(1) When the performance level of a trait is equal to the average performance level of other breeding organizations, its economic weight (i.e. its weighing factor in the breeding goal) is equal to its importance on a commercial level. With lower performance, the economic weight increases. With higher performance, it decreases.

(2) The effect of competitive position on the economic weight of a trait depends on the degree of compensation between traits. When a weakness (negative monetary deviation compared with competitors) n i one trait can be totally compensated by the strength (positive monetary deviation of the same order) i n another trait, then competitive position has no influence on the economic weight.
A note on the effect of different selection criteria on carcass composition in mice
Authors: Hastings I. M. , Hill W. G.
Published: September 2010

Selection can produce lines of animals which diverge widely for a range of characters, so that the genetic relations among these and other traits can be investigated. Results are reported on chemical analysis of whole body composition of 10-week-old mice from replicated lines selected high or low for either amount of lean, proportion of fat, or food intake corrected for body weight. There were over two-fold differences in proportion of fat in lines so selected for fat, whereas those selected for total lean showed little difference in composition. Lines selected for high food intake were no fatter than those selected for low food intake. It is confirmed that dry matter proportion is an accurate predictor of fat proportion.
A note on the usefulness of skinfold thickness v. condition score for estimating body fat content in Boran cattle
Authors: Nicholson M. J. , Little D. A.
Published: September 2010

An attempt was made to use anal skinfold thickness as a quantitative measurement to estimate body fatness in Boran cattle (Bos indicus). Using the normal single-operator technique the relationship between skinfold thickness and the other measurements was poor but was greatly improved by using two operators. It nevertheless remained inferior to body condition score, which was very highly correlated with estimated body fat proportion, It was concluded that condition scoringprovides a valuable index of the nutritional status of Bos indicus cattle, and that measurements of anal fold thickness are not applicable to such animals.
Carcass and meat quality research to meet market needs
Authors: Kempster A. J.
Published: September 2010

The relationship between carcass and meat quality research and industry requirements is examined with reference to changes in consumer demand.

It is argued that much applied research has not focused sharply enough on commercial requirements and that technology transfer has been slow. But there are signs that the pace of future development will be faster, associated with a reorientation of research objectives. The three key factors stimulating change are as follows.

(1) Increasing demand by retailers for a consistent product (a demand enforced by the buying power of the major multiple grocers).

(2) The reappraisal by breeders of selection objectives.

(3) Recent developments in sensor technology and the exploitation of information technology at the producer-processor interface.

The implications of each of these are discussed.

Driven by these factors research will be targeted increasingly on integrated systems from production to consumption, aimed at specific markets setting different balances between production costs and quality. These will be blueprints for best operating practices and the ‘state of the art’ against which new research developments will be evaluated.

Throughout the review, emphasis is placed on the importance of good communication between research workers and industry to confront change and realize the opportunities created.
Operant tests of access to earth as a reinforcement for weaner piglets
Authors: Hutson G. D.
Published: September 2010

Operant methods were used to measure the responsiveness to earth of five groups of seven weaner piglets held in a flat-deck cage. Lifts on a lever produced access to an earth trough, an empty trough, or had no effect. Group lever lifting performance was unaffected by earth in the trough, but at least one individual, the ‘worker piglet’, operated the lever more than the others to gain access to earth. Once the lid of the trough was opened other piglets were attracted to the earth and spent more time using the earth trough than the empty trough. Previous experience of earth appeared to modify lever lifting behaviour. In one group, a worker piglet did not emerge, and in another the worker operated the lever for earth at a reduced rate. The number of piglets using the earth trough and the amount of time spent utilizing it was reduced by prior exposure to earth. It is concluded that earth is a mild reinforcer to weaner piglets, that it will sustain a low rate of responding on an operant schedule, and that a component of its reinforcement value is its novelty.
Cloning and genetic improvement of beef cattle
Authors: Smith C.
Published: September 2010

Cloning of cattle from embryos has been achieved by nuclear transfer. Repeated cloning to produce large clones of genetically identical individuals for commercial use may soon become possible. The main advantage in breeding will come from identifying and using superior clones, selected to fit particular husbandry and marketing niches. Two types of cattle clones will be required, terminal clones chosen for economic merit in production traits, such as growth and carcass traits, and maternal clones chosen for reproduction and maternal traits, such as short calving interval, ease of calving, milking and mothering ability and small mature size. Clonal selection and use will provide several steps of improvement. An initial gain will come by recruiting clones from elite stocks and further responses by selecting the best clones for commercial use. This will reverse the normal improvement lag between breeding and commercial stocks. Heterosis will also be exploited by using crossline clones. For continuous genetic improvement, genetic variation will be maintained by breeding the next generation from a number of selected male and female clones and testing and selecting their progeny, the new set of clones, as before. For maximum improvement rates, both male and female clones will need to be tested. In the short term (5 to 10 years), benefits will come from testing a large number of clones by which gains in economic merit of proportionately 0·15 to 0·30 of the mean can be achieved. Further improvements will come by rebreeding the best clones and testing and selecting the new set of clones from which annual genetic response rates of proportionately 0·02 to 0·03 per year are possible. Cloning thus offers considerable advantages in the improvement of beef cattle.
The effect of avoparcin on the ileal and faecal digestibility of nitrogen and amino acids in the milk-fed calf
Authors: Moughan P. J. , Stevens E. V. J. , Reisima I. D. , Rendel J.
Published: September 2010

The study aimed to determine the effect of the growth promotant avoparcin on the digestion and absorption of nitrogen and amino acids from pre-ruminant milk-fed calves. Eighteen male Friesian calves, 45 kg live weight, were allocated to three diets: a commercial high-quality milk replacer compound (control); control with 100 mg zinc bacitracin per kg (positive control) and control with 40 mg avoparcin per kg. The diets were given once-daily at a set rate of intake during a 14-day metabolic study. On the 15th day the calves were fed at 2-h intervals and ileal digesta were sampled (8 h after the start of feeding) from the euthanazed animal. Estimates of apparent ileal digestibility were determined by reference to an indigestible marker, with the comparable faecal estimates determined following the total collection of faeces.

There was no significant effect of avoparcin or zinc bacitracin addition on faecal apparent digestibility of dry matter, nitrogen, gross energy and amino acids or on ileal apparent digestibility of nitrogen and amino acids. Neither was there a significant effect of either additive on nitrogen retention, daily urinary urea and total nitrogen excretions or portal and peripheral plasma urea concentrations. Ileal apparent digestibility coefficients determined on the control diet ranged from 0-82 for glycine to 0-96 for phenylalanine, tyrosine and methionine. The ileal measures of apparent digestibility were more variable than the comparable values determined over the entire digestive tract. Measurements on the faeces compared with measurements on digesta at the terminal ileum gave higher values (P< 0·05) of apparent digestibility for nitrogen and 10 of the 16 amino acids.