bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of body condition at calving and dietary protein supply on voluntary food intake and performance in dairy cows
Authors: Garnsworthy P. C. , Jones G. P.
Published: September 2010

Four groups of 12 cows were fed from between 12 and 18 weeks before calving to achieve condition scores at calving of 2·0 (T) or 3·5 (F). For 20 weeks after calving all cows were offered 10 kg/day of a dairy concentrate (metabolizable energy (ME) 13 MJ/kg dry matter (DM)) containing 74 g undegradable dietary protein (UDP) per kg DM (groups TH and FH) or 45 g/kg DM UDP (groups TL and FL), 2 kg/day sugar-beet pulp, 5 kg/day brewers' grains and hay ad libitum.

Milk yields were similar for all groups over the first 20 weeks of lactation, but slightly lower for cows in group FL than for other cows. Cows in group FH lost condition over the first 15 weeks and cows in group FL lost proportionally more condition over the first 12 weeks of lactation. Cows in groups TH and TL increased in condition slightly over the first 20 weeks of lactation. After calving, cows in groups TH and TL had significantly higher intakes of DM, digestible DM and ME than did cows in groups FH and FL (P < 0·001). Cows in group TL had higher intakes than did cows in group TH.

Groups TH and FH were in negative energy balance until weeks 10 and 11 respectively. Group FL was in negative energy balance between weeks 4 and 7 and group TL was only in negative energy balance in week 5. The biological efficiency of milk production (energy output in milk/energy intake) was 0·37, 0·35, 0·40 and 0·38 for groups FH, FL, TH and TL respectively.

It was concluded that cows which are thin at calving produce more milk directly from food than cows which are fat and are biologically more efficient; higher UDP levels in the diet led to increased negative energy balances but in thin cows this was due to lower food intakes whereas in fat cows this was due to higher milk yields which led to greater losses of condition.
The direct and residual effects of giving fish meal to dairy cows receiving differing levels of concentrate supplementation in addition to grass silage
Authors: Gordon F. J. , Small J. C.
Published: September 2010

Seventy-eight British Friesian type cows, mean calving date 13 January, were used in a 3 × 2 factorial design experiment to examine the direct and residual responses to replacing 0·8 kg/day of a concentrate containing 184 g/kg crude protein with an equal quantity of fish meal when using three levels of total supplement feeding (0·8, 4·0 and 7·2 kg/day). In addition, all animals had access ad libitum to a high-quality grass silage (in vivo digestible organic matter 750 g/kg dry matter) during the treatment period. Treatments were applied from day 8 post partum until 22 April, when all animals went to pasture, giving a mean treatment period of 91 days. At pasture the animals were rotationally grazed as three groups, based on the three levels of total supplement offered during the treatment period, at the same stocking rate. The effects of treatments in terms of direct effects during the treatment periods, residual effects at pasture and also total lactation were assessed. Also during the treatment period the effects on rumen volatile fatty acid contents and blood composition were monitored. In addition, total diet digestibility and food utilization studies were carried out on six animals per treatment.

Level of supplementation significantly influenced milk output during both the treatment and full lactation periods with the total lactation responses being 2·0 and 1·0 kg milk per kg additional supplement between the food levels of 0·8 to 4·0 and 4·0 to 7·2 kg/day respectively. Level of supplementation also significantly influenced milk fat concentration during the treatment, residual and full lactation periods and milk protein concentration during the treatment period only.

The replacement of 0·8 kg conventional concentrate by 0·8 kg fish meal significantly increased milk yield during the final 21 days on treatment (mean yield per day 20·6 and 21·9 (s.e. 0·44) kg for without and with fish meal treatments respectively) but there were no significant residual or total lactation effects. From the data it was calculated that at low levels of supplementation 0·8 kg fish meal could be used to replace 1·9 kg conventional concentrate but at more moderate levels of nutrition any substitution would be much lower and uneconomic.
Rumen degradability of organic matter, nitrogen and fibre fractions in forages
Authors: Susmel P. , Stefanon B. , Mills C. R. , Spanghero M.
Published: September 2010

Rumen degradability of dry matter (DM), organic matter (OM), nitrogen (N), neutral-detergent fibre (NDF), hemicellulose, cellulose and lignin was evaluated with the in situ technique for maize silage and cocksfoot, timothy, fescue, lucerne and meadow hays. The degradability of each of the six forages was studied separately, each forage being used in turn as the main component of the diet offered to four fistulated cows. For each forage 300 g were mordanted with sodium dichromate and placed in the rumen when the same forage was studied. Faecal grab samples were collected to measure the forage transit time. Digestibility was evaluated using both lignin as an indicator and by an in vitro method.

Rumen outflow rate was higher for cocksfoot and lucerne hays than for maize silage and the meadow, timothy and fescue hays (P < 0·01). The effective degradabilities of DM and OM were higher in maize silage, fescue and lucerne than in cocksfoot, timothy or meadow hay (P < 0·01). Effective degradability of N was highest in lucerne and lowest in timothy and meadow hay (P < 0·01). The degradability of NDF, hemicellulose and cellulose for fescue was always the highest of the six forages (P < 0·01; P < 0·05; F < 0·01 respectively).

Rumen outflow rate was statistically correlated with the c value of DM (r = 0·47), N (r = 0·54), NDF (r = 0·43) and hemicellulose (r = 0·43). High correlations were observed between rate constants of degradation of NDF and hemicellulose, cellulose or lignin (0·93, 0·75 and 0·79 respectively). The regression between in vitro and lignin-derived digestibility was highly significant (P < 0·001, r2 = 0·902 residual s.e. 0·017). The multiple regression analysis between lignin-based digestibility and degradability coefficients, effective degradability and coefficients of faecal chromium excretion was highly significant (r = 0·748; residual s.e. = 0·03).
Evaluation of hypotheses regarding mechanisms of action of growth promotants and repartitioning agents using a simulation model of lamb metabolism and growth
Authors: Sainz R. D. , Wolff J. E.
Published: September 2010

Responses of lambs to cimaterol (CIM), diethylstylbestrol (DES) and ovine growth hormone (GH) were examined using a mechanistic model of growing lamb metabolism. All three compounds increase growth of lean tissue (protein) and decrease fat gain, although the magnitudes of these responses vary. Our working hypothesis was that observed changes in nutrient partition between lean and fat gain were caused by alteration of rate constants for turn-over of muscle protein and fat. Individual experiments were simulated whilst varying values of the protein degradation constant (Kprolein) and Vmax for lipolysis (Kfat). Optimal parameter values were found by minimizing residual errors, calculated as the deviations of model predictions from experimental values for carcass protein and fat. Fitted values of Kfat and Kprotein (expressed as proportions of controls) for each simulation were: CIM (grazing), 1·20 (s.d. 0·05) and 0·86 (s.d. 0·025); CIM (pellet-fed), 1·11 (s.d. 0·115) and 0·87 (s.d. 0·032); DES, 1·33 (s.d. 0·111) and 0·94 (s.d. 0·024); GH, 1·77 (s.d. 0·139) and 0·97 (s.d. 0·025) respectively. These results demonstrate that different mechanisms may be responsible for the changes in carcass composition due to 3-adrenergic agonists, anabolic steroids and growth hormone. CIM probably exerts its effects via changes in protein and fat metabolism, whereas DES and GH appear to act mainly through changes in adipose tissue, with little or no effect on the rate constant for protein turn-over. Carcass composition is less sensitive to manipulation of adipose tissue metabolism than to changes in muscle protein metabolism.
Effect of grain processing on the performance of early-weaned lambs and kids
Authors: Hadjipanayiotou M.
Published: September 2010

The effect of grain processing and form of the concentrate mixture were studied on early-weaned Chios lambs (42 days of age) and Damascus kids (56 days of age). Forty-five, 36, 33 and 33 animals were used in trials 1 (lambs), 2 (lambs), 3 (kids) and 4 (kids), respectively. Within trials animals were divided on the basis of live weight and age into three groups. Treatments (three forms of concentrate mixture) were randomly allocated to one of the three groups. The treatments were: whole cereal (WGP) grains mixed with pellets made from the other ingredients of the concentrate mixture; pelleted (P), where all ingredients were ground and pelleted in 5-mm cubes; rolled cereal grains (RGP), where cereal grains were rolled and then mixed with pellets (5-mm cubes) made from the other ingredients of the concentrate mixture. Cereal grains comprised 774 g/kg concentrate mixture. Fattening diets were based on ad libitum feeding of concentrates and a daily allowance of 01 kg per animal of long lucerne hay. Digestion coefficients, outflow rate of small particles from the rumen and rumen metabolites were measured using five animals per species per treatment.

There were no significant differences between diets for live-weight gain in lambs. On the other hand, kids on the P diet gained more weight and had better food to gain ratio than the other two diets. Feeding the P diet resulted in a significant decrease of acetate and butyrate molar proportion ( P < 0·001) and an increase (P < 0·001) of propionate molar proportion. Similarly, feeding the P diet resulted in a significant reduction in ruminal pH (P < 0·01) and NH,-N (P < 0·05) concentration. Outflow rate (% per h) of small particles from the rumen was lower from lambs and kids on the P diet (P < 0·001). There were no significant differences between species and/or among diets for apparent digestion coefficients and nitrogen balance.
The effect of different proportions of carob pod meal in the diet on the performance of calves and goats
Authors: Louca Avraam , Papas Andreas
Published: September 2010

Four trials with 24 and 38 British Friesian male calves, 39 male Damascus kids and 36 lactating Damascus goats were conducted over a period of 9 months, 6·5 months, 3 months and 12 weeks respectively to study the effects of carob pod meal on growth rate or milk yield. Carob pod meal was used to replace barley at rates from 0 to 30% of the diet. Urea was added to the diets of some of the treatments as a source of supplementary nitrogen.

The final weights and average daily gains of the calves and kids fed on carob pod meal were as good as those of the controls but their feed intakes and feed conversion ratios were higher. The differences in fat-corrected milk between the goats fed on carob pod meal and the controls were not significant. The results showed that carob pod meal constituting up to 30% of the diet had no depressing effects on the growth rate of calves and kids or on the performance of dairy goats, and that the calves and kids could compensate for the lower energy content of carob pod meal by increasing their feed intake.
The digestibility by Friesian steers of dry and acid-treated moist barley offered either whole or rolled in diets containing roughage
Authors: Ahmed F. A. , Topps J. H. , Dempster D. G.
Published: September 2010

1. The digestibility of dry barley and acid-treated moist barley was studied with eight Friesian steers in two consecutive trials each of a duplicated, 2x2 factorial design. In the first trial the diet consisted of either dry or moist (30%) acid-treated barley in the rolled or whole form together with chopped hay; in the second trial rolled or whole, moist (24%) acid-treated barley was given with either chopped hay or silage.

2. No significant difference between the diets in dry-matter intake was observed in the first trial, but in the second trial there was a significantly greater (P< 0·001) intake of dry matter with the hay than with the silage diets.

3. For diets containing either of the moist barleys the digestibility of crude protein was higher when the grain was rolled than when it was whole, the differences being significant (P<0·05) for diets with the 24%-moisture barley. Dry-matter digestibility also was higher for diets containing rolled rather than whole, moist (24%) barley, the difference being significant (P < 0·05) for diets based on silage.

4. Digestibility of starch was significantly greater (P<0·05) when acid-treated moist (24 or 30%) barley was given in the rolled rather than the whole form. Differences in starch digestibility between whole and rolled dry barley were not significant.

5. For all diets the digestibility of crude fibre was greater when the barley was whole than when it was rolled, the difference being significant (P < 0·05) for diets containing hay.
The crude protein requirement of the early-weaned calf given urea, meat meal or soya bean meal with and without sulphur supplementation
Authors: Leibholz Jane , Kang H. S.
Published: September 2010

Two experiments were conducted with 84 male British Friesian calves to estimate their nitrogen and sulphur requirements between 5 and 11 weeks of age. A basal 12 % crude protein (CP) diet was supplemented with meat meal, soya bean meal or urea to 15 or 18 % CP, and with sulphur to reduce the nitrogen to sulphur ratios of the diets to about 10 to 1.

The weight gains and feed conversion ratios of the calves given the 12% CP diets were significantly poorer than those of the calves fed on the diets containing 15 or 18% CP, irrespective of the CP supplement used. The supplementation of the urea-containing diets with sulphur caused a significant increase in feed intake and weight gain.

The digestibility of nitrogen and dry matter increased with increasing CP content of the diets and was greater for the diets supplemented with urea than for those supplemented with meat meal or soya bean meal. Sulphur additions also increased the nitrogen digestibility. The retention of nitrogen, when corrected for feed intake, was greater in the calves fed on the diets containing 18% CP than in those fed on the 15% and 12% CP diets.

The supplementation of the diets with sulphur increased the digestibility of sulphur, its excretion in urine and its retention. The concentration of urea in the blood plasma increased with increasing dietary CP content, and was higher in calves given urea.
Cereal processing and food utilization by sheep 2. A note on the effect of feeding unprocessed barley, maize, oats and wheat on food utilization by early-weaned lambs
Authors: Ørskov E. R. , Fraser C. , McHattie I.
Published: September 2010

An experiment was carried out with 64 lambs to determine the digestibility and efficiency of food utilization of barley, maize, oats and wheat when they were offered whole and loose, or roughly ground and pelleted.

Apparent digestibilities of the organic matter (%) for the four cereals in the order given above were 81·1, 84·3, 69·9 and 82·7 for the whole and 77·2, 82·1, 67·5 and 86·6 for the ground and pelleted grains. The corresponding live-weight gains (g/day) were 340, 345, 241 and 303, and 347, 346, 238 and 323. The corresponding conversions of dry matter (kg) to live-weight gain (kg), over the growth period from 15 to 35 kg weight, were 2·75, 2·52, 3·07 and 2·97 and 2·79, 2·62, 3·33 and 2·56.
Effects of crossbreeding and inbreeding on the frequencies of blood groups in three breeds of sheep
Authors: Rasmusen B. A. , Hall J. G. , Hayter Susan , Wiener G.
Published: September 2010

Blood groups were determined for eight loci in a total of 742 sheep and for theTf(transferrin) locus of 512 sheep comprising the Scottish Blackface, the Cheviot and the Welsh Mountain breeds and their crosses. Each breed and cross was represented by a non-inbred F2generation and by three stages of inbreeding (25, 37½ and 50%). The loci for which all genotypes were distinguished were Hb, M, and Tf, and those for which partial description (including the recessive homozygote) was made were A, B, C, D, R and i.

There were large differences among the three pure breeds only for the frequencies at the Hb and Tf loci. The homozygote frequencies of the Blackface-Welsh and Cheviot-Welsh crosses were approximately half-way between their respective pure breeds. For the Blackface-Cheviot cross the homozygote frequency was considerably lower than either parental breed, suggesting that over all loci there were greater differences in gene frequencies between these two breeds than between the Blackface and Welsh or Cheviot and Welsh.

On average over all loci (except Tf) inbreeding had the effect of decreasing heterozygosity roughly in relation to expectation. Individually this effect was statistically significant only forii, MbMb, HbAHbAandHbbHbb. For the Tf locus there was no average decrease in heterozygosity as a result of 25% inbreeding but thereafter there was a greater decrease in the purebreds than in the crosses.

There were small (< 0·20) but significant residual correlations between R-O-iiblood types and genotypes at several other loci, and betweenddand the M system genotypes.
Voluntary food intake in relation to body weight among British breeds of cattle
Authors: Taylor St C. S. , Moore A. J. , Thiessen R. B.
Published: September 2010

Voluntary food intake and body weight were examined over 4-week intervals between 14 and 70 weeks of age in 306 females from 25 British breeds of cattle. At each age, the relationship of the natural logarithm of voluntary food intake to that of body weight was examined by linear regression both within and between breeds.

Of the total variation in voluntary food intake, the proportion accounted for by body weight was extremely high between breeds (phenotypically, 0·80 or more; genetically 0·88 or more, at most ages) but phenotypically low within breeds (0·33 or less). The mean voluntary intake of a breed at any age could be predicted from its mean body weight at the same age with a coefficient of variation (CV) among breeds that declined with age from 0·08 to 0·04. Within breeds, the corresponding CV for individual intake was between 0·12 and 0·15 beyond 9 months of age, and even higher at early ages.

Within breeds, the regression coefficient of log intake on log body weight was close to the value of 0·7 at all ages. Between breeds, it was over 0·8 at early ages, declining to about 0·7 beyond 1 year of age. Thus, genetically larger breeds voluntarily consumed relatively more food at early ages compared with later ages. Breed size should therefore be taken into account when recommending food intake requirements. Breed deviations for high and low appetite are discussed.
Comparison of sheep and goats under stall-feeding conditions: roughage intake and selection
Authors: Wahed R. A. , Owen E.
Published: September 2010

Three experiments measured intake and assessed quality of roughage refused by individually-fed castrated Saanen goats and Suffolk × Mule wethers, aged 21 months.

In experiment 1, in which long, lucerne hay was offered (10 animals per species; 14 days) goats ate more than sheep (33·2 v. 28·3 g dry matter (DM) per kg M daily; P < 0·05). In experiment 2, in which long, ammonia-treated barley straw was offered (eight animals per species; 21 days) consumption was also higher for goats (21·6 v. 16·4 g DM per kg M daily; P < 0·01). Freshly cut, chopped stinging nettle (Urtica dioica L.) was offered with treated straw in experiment 3 (eight animals per species). Over the 10 days, intake of nettle increased linearly and that of straw decreased, but nettle consumption was consistently higher for goats than sheep.

In each experiment, food refusals (0·2 of food offered) were of lower nutritive value (lower nitrogen, higher acid detergent fibre, lower digestibility in vitro) than food offered. Throughout, food refusals by goats were of slightly higher nutritive value than food refusals by sheep.

It is concluded that both sheep and goats are selective feeders under stall-feeding conditions, but the greater intake of roughage by goats cannot be attributed to their selection of more nutritive components.
The effect of nutrition on the reproductive performance of first-litter sows 3. The response to graded increases in food intake during lactation
Authors: King R. H. , Dunkin A. C.
Published: September 2010

Seventy-two animals were used in an experiment to study the response of first-litter sows to graded increases in daily food intake during a 28-day lactation. Six food intakes, ranging from 1·5 to 4·8 kg/day were compared. The results showed that both live-weight loss and backfat loss during lactation increased linearly as food intake decreased (P < 0·01).

Subsequent ovulation rate was unaffected by food intake but both weaning to mating interval (Y,, days) and the proportion of sows exhibiting oestrus within 8 days of weaning (Y2)improve d linearly with increase in daily food intake during lactation (X, kg) (P < 0·01); the respective linear regressions being Y, = 39·0 - 6·26 and Y2 = 0·198A - 0·15. A sub-group of 24 gilts which were older at first conception (340·5 v. 213·5 days; P < 0·01) exhibited oestrus sooner after their first litters were weaned (12·8 v. 22·1 days; P < 0·05) than the remaining 48 younger animals.

Nitrogen balance increased linearly with food intake (P < 0·01) but even at the highest food intake, nitrogen balance remained negative (−15·5 g N per day). Food intake had no effect on the growth rate of piglets to 3 weeks of age but in the 4th week of lactation there was a quadratic increase in piglet growth rate as sow food intake increased (P < 0·01).
16-androstene steroids in the submaxillary salivary gland of the boar in relation to measures of boar taint in carcasses
Authors: Booth W. D. , Diane Williamson E. , Patterson R. L. S.
Published: September 2010

Fifteen Large White boars were randomly allocated to three groups of five pigs. The boars were slaughtered over a period of time at one of three live weights: group 1 (pork weight), 63 to 68 kg (mean age 141 days), group 2 (bacon weight), 90 to 97 kg (mean age 203 days) and group 3 (heavy weight), 121 to 133 kg (mean age 268 days). Testes, bulbourethral glands, submaxillary salivary glands, blood and thoracic fat were taken from each pig and the glands weighed and steroids determined in extracts of the submaxillary glands, blood plasma and fat. Testosterone and the boar taint steroid, 5a-androstenone (5a-androst-16-en-3-one) were measured in plasma by radioimmunoassay (RIA). 3a-androstenol (5a-androst-16-en-3a-ol) and 5a-androstenone were determined separately in submaxillary glands by gas-liquid chromatography and together semi-quantitatively by a colour reaction. 5a-androstenone was also determined in submaxillary glands by RIA and in fat by enzyme-linked immunosorbent assay. Mean somatic characteristics differed significantly between the groups, but due to the wide variation in steroid concentrations between individual boars, mean differences for steroid concentrations between groups were not significant.

Significant positive correlations were found in boars between bulbourethral gland weight, submaxillary gland weight, concentrations of 3a-androstenol and 5a-androstenone in the submaxillary gland and concentrations of free plasma 5a-androstenone and fat 5a-androstenone (P < 0·05). The application of a simple colour reaction to detect readily extractable 16-androstene steroids (16-androstenes) in submaxillary gland tissue is discussed in relation to other methods for determining boar taint.
A test of a free-access two-level pen for fattening pigs
Authors: Fraser D. , Phillips P. A. , Thompson B. K.
Published: September 2010

Two prototype two-tiered pens were constructed for fattening pigs. The pens consisted of a solid or porous upper floor located 0-8 m above a slatted lower floor, with a short ramp joining the two levels. Food was available only on the upper level and water only on the lower. Eleven groups, each of 15 to 18 pigs were housed in the two-tiered pens for 8 weeks, starting at 10 weeks of age, while matched control groups were housed in a conventional pen offering the same amount of total floor space. During the 1st week, some pigs were slow to adapt to the two-tiered system and average weight gain was lower than in the control pen. Over the 8 weeks, however, weight gain and food conversion ratios were very similar in the two pen types. The animals made effective use of the two levels, and kept the upper level free from dung. Physical condition of pigs in the two-tiered pen was as good as, or better than, that of the controls. The two-tiered design offers several potential advantages in terms of animal production and behavioural problems.
Succinylcholine and halothane as a field test for the heterozygote at the halothane locus in pigs
Authors: Webb A. J. , Imlah P. , Carden A. E.
Published: September 2010

Reaction to the muscle relaxant succinylcholine was investigated as a possible method of distinguishing the heterozygote from the normal homozygote at the halothane locus. Totals of 54 assumed heterozygotes and 67 assumed homozygotes received intravenous succinylcholine during halothane anaesthesia at 6 to 10 weeks of age. Three separate measures of the duration and severity of the muscular reaction to succinylcholine were all significantly increased in heterozygotes compared with homozygotes. The genotypic difference for one of the three reaction traits was significantly influenced by the day of testing. Due to overlapping distributions for the two genotypes, succinylcholine reactions did not offer a precise method of identifying individual heterozygotes. Although test mating to recessive homozygotes would still be required to be certain of eliminating the halothane gene, the gene frequency among prosepective parents for test mating could be substantially reduced by succinylcholine screening. Due to the expertise and time required, succinylcholine testing would probably only be worthwhile for the production of specialized homozygous lines at nucleus level.
Effect of body condition at calving on the health and performance of dairy cows
Authors: Treacher R. J. , Reid I. M. , Roberts C. J.
Published: September 2010

Two groups of nine British Friesian cows were fed from about 32 weeks before calving to achieve condition scores at calving of 2·5 (thin) and 4 (fat). For 10 weeks after calving all cows were offered 7 kg hay daily in four feeds, with concentrates given five times daily according to appetite.

During early lactation, the group of fat cows had lower dry-matter intakes and daily milk yields and yielded less milk protein and lactose than the group of thin cows. The mean yield of milk over the whole lactation was 500 kg less in the fat cows but the difference was not significant. The fat cows lost 48 kg body weight and 1·20 units condition score during early lactation compared with 27 kg body weight and 0·52 units condition score in the thin cows. No difference in reproductive performance was found between the two groups but significantly more cases of disease occurred in the fat cows than in the thin cows.

It is concluded that cows that are fat at calving eat less than thin cows, give the same or less milk than thin cows, mobolize more body tissue and lose more weight after calving than thin cows and suffer more disease.
Effects of high levels of body condition and food intake on plasma follicle stimulating hormone, luteinizing hormone, prolactin and progesterone profiles around mating in Greyface ewes
Authors: Rhind S. M. , Leslie I. D. , Gunn R. G. , Doney J. M.
Published: September 2010

Two groups of 19 Border Leicester cf × Scottish Blackface 9 ewes were fed so that ewes of one group were in a very high level of body condition at mating (mean score 3·35) and had a high level of intake. Ewes of the second group were in moderately high condition (mean score 2·74) and were given a live-weight maintenance ration. Ewes in the high group had a higher ovulation rate than those of the moderate group (3·36 v. 2·33) but a lower number of embryos per ewe mated (1·16 v. 1·42). Mean follicle stimulating hormone profiles were similar for ewes of the two groups during the luteal and follicular phases of the cycle before mating and during the subsequent oestrus. Mean prolactin concentrations were higher in ewes of the high group during the follicular phase and oestrus but not during the luteal phase. Mean luteinizing hormone (LH) concentrations were higher in ewes of the high group during the follicular phase and oestrus but not during the luteal phase. Mean LH concentrations were similar for the two groups at all times but the frequency of LH pulses was higher in the high group during the follicular phase.

Ewes that were not pregnant at slaughter had abnormal progesterone profiles following mating, abnormal pre-ovulatory LH surges or failed to show oestrus. These abnormalities were not related to gonadotrophin profiles prior to oestrus.
Amino acid requirements of growing pigs 8. The response of pigs from 50 to 90 kg live weight to dietary ideal protein
Authors: Yen H. T. , Cole D. J. A. , Lewis D.
Published: September 2010

The response to dietary lysine when provided as part of an ideal protein was examined in pigs over the range of live weight from 50 to 90 kg. Ninety-six pigs, 32 trios of littermate boars, castrated males and gilts were allocated to eight diets with lysine concentrations of 5·6, 6·2, 7·3, 8·3, 9·3, 10·3, 11·4 and 12·4 g/kg diet and corresponding concentrations of crude protein (CP) from 90 to 186 g/kg diet (all having a digestible energy of 13·38 MJ/kg). Pigs were given food on a restricted scale once daily. With increasing lysine concentration, there was a linear response (followed by a plateau) for growth and carcass characteristics up to dietary lysine concentrations of 91, 7·2 and 8·4 g/kg diet and CP concentrations of 142, 116 and 132 g/kg diet with daily lysine intakes of 22·9, 18·6 and 21·2 g and CP intakes of 357, 290 and 331 g for boars, castrated males and gilts respectively.
Wilting of herbage prior to ensiling: effects on conservation losses, silage fermentation and growth of beef cattle
Authors: Charmley E. , Thomas C.
Published: September 2010

A sward of perennial ryegrass was either directly ensiled at 181 g dry matter (DM) per kg fresh weight with formic acid applied at 3·6 1/t fresh material or wilted for 65 h to achieve a DM concentration of 407 g DM per kg. Physical and respiration loss were measured in the field and losses during ensiling were estimated from buried bags. The silages were offered to 58 British Friesian steers, initially 3 months of age and 101 kg live weight (LW). Ten steers were allocated to an initial slaughter group and the remainder were offered the two silages either ad libitum or at two restricted levels of feeding. These animals were slaughtered after a mean period of 112 days to estimate the increments in the components of the body.

Loss of DM in the field increased from 4·3 to 86·6 g/kg on wilting and proportionately 0·75 of this additional loss was due to respiration. The fermentation characteristics of the silages were broadly similar except that the concentration of ethanol was higher in the unwilted than in the wilted silage (57·6 v. 5·6 g/kg DM). Losses of DM during ensiling were slightly higher with the unwilted (104·4 g/kg ensiled) than with the wilted (80·1 g/kg) material. Losses of nitrogen were relatively higher and energy losses lower than was the loss of DM.

Wilting significantly depressed the digestibility of gross energy from 0·651 to 0·631 (P < 0·001) and at the ad libitum level steers ate proportionately 006 more wilted silage (P > 0·05) resulting in similar intakes of digestible energy. At the ad libitum level of feeding steers given wilted silage gained more LW (+55 g/day) and empty-body weight (+64 g/day) than those given unwilted silage (P < 0·05). However, steers given wilted silage contained less fat and energy in the empty body at slaughter than those given unwilted silage. Thus, wilting did not influence the efficiency of utilization of digestible energy for energy retention nor the efficiency of utilization of dietary protein for protein gain. Since efficiencies by the animal were similar and also the increased field loss on wilting was partly compensated for by a reduced silo loss, it is concluded that the proportion of energy and protein in the standing crop retained by the steers is unaffected by wilting (65 and 64 kJ/MJ and 125 and 138 g/kg N for unwilted and wilted systems respectively). Further work is needed to establish the effect of wilting for a shorter period than in the current trial by increasing the drying rate of herbage.
Breed and sex differences in equally mature sheep and goats 1. Growth and food intake
Authors: Thonney M. L. , Taylor St C. S. , McClelland T. H.
Published: September 2010

Genetic size-scaling accounts for most of the variation found among mammalian species in food intake and growth rate, with food conversion efficiency independent of the body size of the species. Is the same true of breeds and strains within species?

Animals from Soay, Welsh Mountain, Southdown, Finish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and from a breed of feral goats were grown to 0·40, 0·52, 0·64 or 0·76 of the mean mature weight of their breed and sex. Food was offered ad libitum and individually recorded.

Allometric growth coefficients were obtained for fleece weight, femur weight and femur length. Fleece was late maturing and femur early.

Breed and sex size-scaling coefficients, obtained by regression of breed and sex means on mature size, were similar to those found at the species level for age from conception to slaughter, time taken to mature and food conversion efficiency. Coefficients were higher than expected for total and daily food consumption, especially at early stages of maturity. Most breed coefficients were close to expectation while sex coefficients were somewhat higher than expected.

There were significant breed deviations: Welsh Mountain, Oxford Down and probably Soay sheep required less time and Jacob sheep and feral goats required more time to mature than expected from differences in mature size. Soay and Welsh Mountain sheep appeared to be more efficient and feral goats and Jacob sheep less efficient food converters over the same maturity interval.
Changes in body composition relative to weight and maturity of Australian Dorset Horn rams and wethers 4. Adipocyte volume and number in dissected fat partitions
Authors: Thompson J. M. , Butterfield R. M.
Published: September 2010

The effect of castration on the cellular characteristics of dissected fat partitions was examined in 20 Dorset Horn rams and 20 Dorset Horn wethers. Cellular characteristics of dissected carcass (subcutaneous and intermuscular partitions) and non-carcass (kidney fat, omental and mesenteric partitions) fat partitions were examined in 13 mature animals, and the rate of change in adipocyte volume relative to the change in chemical-fat weight in that partition, examined in 27 immature animals.

Mature wethers had a greater concentration of chemical fat in the subcutaneous fat partition than mature rams (917v. 885 g/kg, respectively). This, in combination with a greater weight of dissected subcutaneous fat, resulted in a greater weight of chemical fat in the subcutaneous partition of wethers compared with rams. Mature wethers had larger adipocytes than mature rams in all dissected fat partitions, with the largest increase in the subcutaneous and omental fat partitions. The increased adipocyte volume in the dissected fat partitions in mature wethers resulted in a smaller total estimated number of adipocytes in all carcass and non-carcass fat partitions compared with mature rams.

Standardized allometric coefficients for adipocyte volume relative to chemical-fat weight in that partition showed that increases in chemical-fat weight were due to a combination of hypertrophy and hyperplasia. In the omental and kidney fat partitions, hypertrophy contributed more to the increase in chemical-fat weight in wethers compared with rams.
Effects of floor area allowance on performance of growing pigs kept on fully slatted floors
Authors: Edwards S. A. , Armsby A. W. , Spechter H. H.
Published: September 2010

The experiment compared four different space allowances for growing pigs housed on fully slatted floors. Space allowance (A m2) was defined in relation to live weight (M kg) of the pigs according to the equation A = kM0·67, using values for the constant (it) of 0·024, 0·027, 0·030 and 0·034. Six replicate pens of 12 pigs were housed on each treatment in a controlled environment building. Food was given ad libitum and from 34 kg until slaughter at 85 kg pigs were individually weighed each week and the pen size was adjusted according to the appropriate equation. Increasing space allowance increased live-weight gain (844, 862, 883, 897 (s.e.d. 14·4) g/day). Differences in killing-out proportion reduced the effect on final carcass weight (63·3, 63·9, 64·1, 64·5 (s.e.d 0·82) kg). Daily food intake was unaffected by treatment but food conversion ratio was significantly poorer at the lowest space allowance (2·70, 2·56, 2·60, 2·59 (s.e.d. 0·043) kg/kg). Economic analyses of the results indicated an adverse effect on profitability of space allowance less than that defined by the equation A(m2) = 0·027 M0·67 (kg). A minimum allowance defined by the equation A (m2) = 0·030 M0·67 is recommended in commercial practice for pigs in fully slatted housing.
Effect of litter size on herbage intake at pasture by ewes and their progeny
Authors: Vulich S. A. , O'Riordan E. G. , Hanrahan J. P.
Published: September 2010

Thirty-four mature ewes (17 rearing twins and 17 rearing singles) were used to examine the effect of litter size on herbage intake at pasture by ewes over the course of lactation; intake by their lambs during weeks 13 to 15 of lactation was also evaluated. Daily organic matter intake (OMI) was estimated using the n-alkane technique. Ewes and lambs rotationally grazed 19 × 0·15-ha paddocks during the experimental period which extended from week 2 of lactation to weaning at week 15 of lactation. Sward conditions were maintained steady throughout with daily OM allowance per ewe varying between 4·6 and 5·7 kg and dry matter digestibility between 763 and 858 g/kg DM.

Throughout lactation OMI and OMI per kg body weight were higher for twin-rearing ewes (P < 0·05) than for ewes rearing singles: 2·50 and 2·26 kg/day, and 38 and 32 g/kg per day, respectively. Intake reached a maximum on weeks 6 to 7 of lactation. From weeks 13 to 15 of lactation, OMI and OMI per kg body weight for single- and twin-reared lambs were 1·09 and 1·14 kg/day, and 31 and 36 g/kg per day, respectively.

The combined food intake per dam-offspring unit for weeks 13 to 14 of lactation for a ewe plus her single lamb was 2·8 kg OM per day compared with 4·3 kg OM per day for a ewe plus her two lambs. The repeatability of average weekly intake by ewes was 0·39 over the course of lactation and 0·40 for lambs over the 13 to 15 week period. Repeatability estimates for ewes increased slightly when data from weeks 3 to 7 and weeks 13 to 14 was analysed separately (0·42 and 0·53, respectively).
Partial milking of cattle in smallholder herds on the Accra Plains: some factors affecting daily partial milk yield and milk composition
Authors: Okantah S. A.
Published: September 2010

Daily partial milk yield of Sanga cows in 13 smallholder agropastoralist herds at two locations on the Accra Plains was recorded through monthly sampling. Estimates of mean daily partial milk yield and milk composition were computed from 1266 observations. The unadjusted mean daily partial milk yield was 875 (s.e. 11) g. The composition of milk: total solids (TS), fat (F) and solid-not-fat (SNF) were 131 (s.e. 14), 41 (s.e. 11) and 90 (s.e. 7) g/kg respectively. Least squares estimate of mean daily partial milk yield were 808·2 and 462·4 g with average s.e. of 41·8 for wet and dry season respectively. The wet and dry season differences in daily partial milk yield, TS and F were highly significant (P < 0·01). Seasonal difference in SNF was not significant.

Herd difference in partial milk yield, TS, F and SNF were highly significant (P < 0·02). There were no significant effects of location on daily partial milk yield and SNF, although location effects on F and TS were significant (P < 0·05). The highest milk yield was observed in cows in third lactation and the lowest in cows in seventh lactation (P < 0·01). Daily partial milk yield peaked in the 3rd month of lactation. On average, lactation length was 210 to 240 days. Both linear and quadratic effects of stage of lactation were highly significant (P < 0·01). Lactation curve parameters for partially milked cows were also estimated. The implications of the results for milk production in sub-Saharan Africa were discussed.
A note on growth curves for the ostrich (Struthio camelus)
Authors: du Preez J. J. , Jarvis M. J. F. , Capatos D. , de Kock J.
Published: September 2010

The Gompertz equation was used to compute growth curves for three groups of ostriches (Struthio camelus), from Oudtshoorn in South Africa, the Namib desert in Namibia and from Zimbabwe. All were reared under typical intensive farm conditions with ad libitum feeding. There were no significant differences in mature mass between regions but the maximum daily weight gain for males occurred later (day 163) for Oudtshoorn birds, compared with day 121 for Namibian and day 92 for Zimbabwean. Oudtshoorn females reached maximum rate of gain on day 175 compared with day 115 for Namibian and day 114 for Zimbabwean. Comparisons might prove important when planning programmes for the genetic improvement of commercial flocks, but possible influences of food composition and environment should be investigated.
Influence of diet composition, dry-matter intake, milk production and energy balance on time of post-partum ovulation and fertility in dairy cows
Authors: Lucy M. C. , Staples C. R. , Thatcher W. W. , Erickson P. S. , Cleale R. M. , Firkins J. L. , Clark J. H. , Murphy M. R. , Brodie B. O.
Published: September 2010

Lactating Holstein-Friesian cows from two calving groups (no. = 90) were studied during the early post-partum period to determine the effect of dry-matter intake (DM1), 40 g/kg fat-corrected milk (FCM) production, energy balance (EB), parity, and food additives (calcium salts of long-chain fatty acids [CaLCFA] and niacin) on the recrudescence of ovarian function and establishment of pregnancy. Cows that ovulated early during the post-partum period (15 to 21 days after calving) consumed more food and tended to produce more FCM compared with cows ovulating later (22 to 42 days or after 42 days). Primiparous cows had lower EB and tended to have longer intervals to first ovulation compared with multiparous cows but the average interval to pregnancy was similar for primiparous and multiparous cows. Feeding CaLCFA tended to extend the interval to first service and decreased pregnancy rate. Production characteristics (including DMI and FCM production) seem to determine interval from calving to first ovulation as well as interval from calving to pregnancy (days open). Fertility was affected negatively by feeding CaLCFA.
Correlated responses in slaughter and carcass traits of crossbred progeny to selection for carcass lean content in sheep
Authors: Cameron N. D.
Published: September 2010

Correlated responses in slaughter and carcass traits to divergent selection for high or low carcass lean content in Texel-Oxford sheep were measured in the crossbred progeny of 23 rams. Rams were selected using the selection index: -0·995 FATD + 0·206 WT20, where FATD and WT20 are the ultrasonic backfat depth and live weight at 20 weeks of age, with both traits standardized to have zero mean and unit phenotypic variance. A total of 329 crossbred lambs were slaughtered at 16 weeks of age and 250 lambs were slaughtered at fixed weight, 38 to 40 kg for castrated males and 36 to 38 kg for ewe lambs. Progeny from high-line rams grew faster, as indicated by the heavier slaughter weight of lambs slaughtered at fixed age (04 (s.e.d. 0·5) kg) and the lower age at slaughter for lambs slaughtered at fixed weight (-5 (s.e.d. 3) days). Subcutaneous and internal fat scores and the Meat and Livestock Commission carcass appraisal and conformation scores were all lower in the high line than in the low line and the magnitude of the selection line differences for lambs slaughtered at fixed weight was essentially double that of lambs slaughtered at fixed age (0·8 v. 0·5 score units).

Shoulder joints of 254 lambs, slaughtered at fixed age, were dissected and half carcasses were dissected on 66 of the lambs. Carcass and shoulder joint information was combined with double-sampling methodology, using multiple regression equations to predict carcass composition. For each tissue type, viz. lean, subcutaneous fat, internal fat and bone, the correlations between carcass content and shoulder joint content were at least 0·90 and the proportions of variation in carcass tissue content accounted for by the prediction equations were also at least 0·90. Progeny of high-line rams had higher carcass lean weight, (402 (s.e.d. 140) g) than progeny from the low line, with no difference in carcass fat weight, such that carcass lean content was higher, (10 (s.e.d. 5) g/kg), and carcass fat content was lower, (-10 (s.e.d. 7) g/kg). Based on the slaughter and carcass traits of these crossbred progeny, divergent selection for high and low carcass lean content has established lines of animals with different rates of lean growth but similar rates offat deposition.
Changes in body components of autumn-calving Holstein-Friesian cows over the first 29 weeks of lactation
Authors: Gibb M. J. , Ivings W. E. , Dhanoa M. S. , Sutton J. D.
Published: September 2010

Changes in body composition of 54, second to fourth parity, autumn-calving Holstein-Friesian dairy cows offered grass silage ad libitum and 3(L), 6(M) or 9(H) kg concentrate dry matter per day were measured by serial slaughter at 0, 2, 5, 8, 11, 14, 19, 24 and 29 weeks post partum.

Concentrate level had a significant effect on the fresh weights of many of the body fractions with the differences generally being greater between L and M than between M and H. Increasing concentrate level generally reduced the extent of weight loss of body fractions in early lactation and enhanced subsequent repletion. Empty body weight decreased to week 8 and then increased steadily over the remaining 21 weeks, but within this pattern different organs were concomitantly increasing and decreasing. Carcass weight and the weights of the internal fat depots showed a decline over the first 8 weeks and a subsequent increase, udder weight declined throughout, weights of various sections of the digestive tract showed an initial increase then remained steady, whilst liver weight increased throughout.

In week 0 the carcass accounted for proportionately 0-61 of the total energy in the body (6278 MJ), of which fat and crude protein (CP) comprised proportionately 0·67 and 0·33, respectively. In early lactation mobilization of fat and CP in the carcass was reduced with increasing level of concentrate. In the non-carcass fraction increasing concentrate level led to a higher weight of CP in the metabolically active organs such as the digestive tract and udder but had little effect on the weight of fat. Nevertheless, there was generally a positive effect of concentrate level on energy content. Total weights of fat, CP and water in the body declined to week 8 then increased over the following 21 weeks. Although weight of CP in the liver increased throughout lactation and weight of fat was elevated in weeks 0 and 2, the energy content of the liver remained fairly constant.

Estimates of the change in net energy (NE) associated with live-weight loss and with live-weight gain showed a slight though non-significant difference between the two, despite evidence of a higher concentration of fat associated with gain than with loss, and CP concentration being the same in both cases. The mean value was 19·3 MJ/kg live-weight change.