bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological attributes as possible selection criteria for milk production 3. Plasma hormone concentrations and metabolite and hormonal responses to changes in energy equilibrium
Authors: Land R. B. , Carr W. R. , Hart I. C. , Osmond T. J. , Thompson R. , Tilikaratne N.
Published: September 2010

Plasma hormone concentrations and metabolite responses to changes in energy equilibrium were measured in experiments designed to compare a) Hereford × Friesian with Friesian calves and b) Friesian calves sired by bulls with a high level of Improved Contemporary Comparison with those sired by bulls of a low level. The concentration of thyroxine and triiodothyronine tended to be greater in calves of higher dairy merit. The concentration of growth hormone was largely unrelated to dairy merit in the circumstances studied. The concentration of insulin was greater in Hereford × Friesian than in Friesian calves following feeding and following the injection of propionate. Responses to the injection of insulin and of growth hormone (as measured by changes in the plasma concentration of urea nitrogen, free fatty acids, glucose or the other hormone) were little affected by the level of Improved Contemporary Comparison of a calfs sire.

It was concluded that the thyroid system and the response of insulin to perturbation of energy balance may provide criteria of genetic merit for milk production which are neither age- nor sex-limited.
Optimal mature size of angus cows for maximum cow productivity
Authors: Stewart T. S. , Martin T. G.
Published: September 2010

Lifetime maternal performance records of 113 Angus cows born over a 12-year period were used to estimate the relationship between cow size characters, mature size (A) and maturation rate (K), and lifetime maternal performance characters, years in the herd (YH), number of calves (NC), total calf weight (TW), average calf weight at weaning (AW) and calf weight per year in herd (kg/year). Pertinent reproductive management of the herd was: heifers were mated to calve as 2-year-olds; any heifer failing to calve or any cow failing to wean a calf a second time was culled; all matings were to purebred Angus sires. Mean cow mature size was 487 ± 5 kg with a maturation rate of 0·058 ± 0·001. Means for maternal characters were: YH, 7·4 ± 0·4; NC, 6·4 ± 0·3; TW, 1283 ± 71; AW, 200 + 1·8; and kg/year, 173 ±5·1. The correlations between maternal characters and A and K, respectively, were: YH, −0·21, 0·15; NC, −0·21, 0·15; TW, −0·16, 0·12; AW, 0·20, −0·15; and kg/year, 0·05, −004. The regression of maternal characters on mature size was quadratic in every instance with optimal cow size for each character being: YH, 468; NC, 465; TW, 471; AW, 493; and kg/year, 475. The optimal cow size for average weight of calf weaned was 18 to 25 kg heavier than the optimal size for those characters associated with fertility. Relationships between maturation rate and maternal performance were not statistically significant.
A note on synchronization of oestrus in post-partum cows with prostaglandin F2α and a progesterone-releasing device
Authors: Beal W. E.
Published: September 2010

Suckling post-partum cows treated for oestrous synchronization exhibited oestrus and became pregnant earlier in the mating period than untreated cows. Combined treatment with a progesterone-releasing device and prostaglandin F2α synchronized oestrus in a greater proportion of the cows than treatment with prostaglandin Fα alone (P < 0·01). The combined treatment appeared to induce ovarian activity in post-partum anoestrous cows that were approaching their first ovulation.
Hormone and metabolite concentrations in beef steers of two maturity types under two systems of production
Authors: Beeby Janet M. , Swan H.
Published: September 2010

Sixteen British Friesian-cross steers of early- or late-maturity types were reared on either a 16- or a 24-month system of production. The steers on the 24-month system were subjected to a reduced nutrient intake during two phases of growth: 1) during early growth when the steers were approximately 9 months old and 2) during a store period when the steers were 13 to 19 months old. Animals on the 16-month system were fed to appetite throughout. Blood sampling was carried out at various periods during growth and serum samples were analysed for growth hormone, insulin, prolactin, glucose and blood urea nitrogen. Serum growth hormone concentrations were elevated during reduced nutrient intake, whilst serum insulin concentrations fell. Serum prolactin followed a seasonal pattern, but was lower in the underfed steers. Serum glucose concentrations also tended to fall during underfeeding, but blood urea nitrogen results were inconclusive. Hormone concentrations were not influenced by the maturity type of the steer, suggesting that the hormones measured are not primarily involved in determining the differential growth patterns in steers of different maturity types.
Effects of season of birth, breed of sire and sex of calf in a single-suckled Aberdeen Angus Holstein beef herd
Authors: Wilson L. L. , Abdul-Jamak E. , LeVan P. J. , Todd R. F. , Watkins J. L. , Ziegler J. H.
Published: September 2010

Data were obtained from 233 heifers and 246 steers born in the autumn (September) or spring (March) seasons. The calves were sired by Polled Hereford (British) and Charolais, Chianina, Limousin. Maine- Anjou and Simmental (Continental European) bulls, from Aberdeen Angus (♂ × Holstein ♀ cows. Autumn-born calves weighed more at birth than did spring-born calves ( P < 0·01 ). Season of birth did not affect 205-. 305-. 365-day or slaughter weights. Incidence of dystocia was greater for Maine-Anjousired calves than for Polled Hereford calves (P < 0·05) with the other breeds intermediate. Significant sex differences were observed in practically all live and carcass traits with the exception of Warner- Bratzler tenderness and taste panel evaluations.

There were significant breed effects in which Continental European-sired calves gained weight more rapidly than did Polled Hereford-sired calves (P < 0·01) within each 90-day period, with the exception of 180 to 270 days. Slaughter weight and carcass weight per day of age followed the same trend. At slaughter at a mean age of 416 days, mean live weight of calves from Continental European breeds of sire was 1·075 of that of the Polled Hereford-sired calves. Proportion, weight and gain per day of edible meat in the carcass were greater for calves sired by Continental European bulls (P < 0·01). Although fat thickness and marbling score means were greater for Polled Hereford-sired cattle (P < 0·01), there were no significant differences in taste panel evaluations. There were no important two-way interactions between the main effects (sex, season of birth or sire breed).
High mating frequency for boars: predicting the effect on sexual behaviour, fertility and fecundity
Authors: Hemsworth P. H. , Winfield C. G. , Hansen C.
Published: September 2010

In the first experiment there were significant correlations between the average product of the length and width of the boar's testicles and the sperm output of the boar under a high collection frequency over two 6-h periods and over a 6-week period (r = +0·80, d.f. = 4, P < 0·05 and r = +0·77, d.f. = 7, P < 0·05, respectively). In the second experiment there were no significant differences in the fertility or fecundity of mature boars that had either two or six copulations per week over a 25-week period. However, there was a significant correlation between the average width of the boar's testicles and the fertility of the boar under the high mating frequency (r = +0·74, d.f. = 8, P < 0·05). There were also significant correlations between the number of copulations achieved in two mating tests and the number of copulations achieved and the refusal rate to mate under the high mating frequency (r = +0·86, and r = –0·89, respectively, d.f. = 6, P < 0·01). The implication of these results to the development of tests to predict mating performance of boars is discussed
Studies in the prophylaxis of induced copper deficiency in sheep grazing reseeded hill pastures
Authors: Whitelaw A. , Russel A. J. F. , Armstrong R. H. , Evans C. C. , Fawcett A. R. , Davies G. J.
Published: September 2010

The paper reports an experiment conducted with 50 Scottish Blackface and 10 South Country Cheviot ewes all suckling twin lambs and grazing, from parturition for some 18 weeks, pasture previously shown to cause a molybdenum-sulphur induced copper deficiency. The objectives were to examine the efficacy of various means of prophylaxis and the susceptibility of the two genotypes to copper deficiency.

The treatment of ewes at parturition with copper, either as an injection of 90 mg copper as copper methionate or orally with cupric oxide needles (3·2 g copper), delayed the onset of signs of copper deficiency in their lambs but did not prevent completely the development of hypocupraemia or hypocuprosis.

The treatment of lambs with a single injection of 15 mg copper as copper calcium edetate at about 6 or 10 weeks of age was not effective in preventing the development of hypocupraemia. Four injections (1 × 5 mg and 3 × 15 mg) at approximately equal intervals maintained normocupraemic values in lambs, but the most effective treatment, as judged by plasma and liver copper concentrations and by live-weight gain, was the administration of cupric oxide needles (1.6 g copper) to lambs at about 6 weeks of age.

The between-genotype comparison indicated that the Cheviot ewes and their lambs were as severely affected by the induced copper deficiency as were the Blackfaces.
Nursing and suckling behaviour of sows and their litters before and after grouping in multi-accommodation pens
Authors: Bryant M. J. , Rowlinson P.
Published: September 2010

Two groups of six sows and their litters were observed continuously the day before (day 19 post partum) and the 2 days following (days 20 and 21) movement from individual farrowing crates to multiaccommodation pens. Grouping was associated with a decline in the frequency of true nursing events, particularly in the 6-h period immediately following grouping, and with an increase in the number of false nursing events. There was a trend for a reduction in the duration of the milk let-down phase of the suckling sequence in four litters studied in detail and cross suckling was observed in all four litters. Lactational oestrus occurred in nine of the 12 sows. The study yielded little evidence for an association between nursing and suckling behaviour, and the occurrence of lactational oestrus.
A note on effects of glyphosate and quinine on the palatability of hay for sheep
Authors: Jones R. , Forbes J. M.
Published: September 2010

Six sheep were used in a Latin-square experiment to investigate the effect of pre-harvest treatment of pasture with glyphosate (Roundup, a translocated herbicide) on the palatability of hay. Four hays were used: control (C), Roundup (R), quinine (Q, 100 mg/kg) and Roundup with quinine (QR). During each week one of the following choices was given to each animal: (a) C/C; (b) C/R; (c) R/R; (d) Q/C; (e) Q/R; and (f) C/QR. There were no significant effects of treatment on the proportion chosen or on total daily intake, mean meal size or rate of eating. It was concluded that neither pre-harvest treatment with Roundup nor post-harvest treatment with quinine affected the palatability of hay.
Influence of energy source and dietary protein degradability on the voluntary intake and digestibility of barley straw by pregnant beef cows
Authors: Alawa J. P. , Fishwick G. , Parkins J. J. , Hemingway R. G. , Aitchison T. C.
Published: September 2010

Three experiments, designed as three simultaneous 4 × 4 Latin squares (21-day feeding periods), were conducted using pregnant beef cows. Diets were based on barley straw given ad libitum together with 1·7 kg dry matter (DM) of either molassed sugar-beet pulp (MSBP) (experiment 1), unmolassed sugarbeet pulp (USBP) (experiment 2), or rolled barley (BARLEY) (experiment 3). In the respective experiments, MSBP, USBP and BARLEY were given either alone, to provide about 200 g crude protein (CP) per day (CONTROL) or were supplemented with urea (U), untreated soya-bean meal (SBM) or formaldehyde-treated soya-bean meal (FT-SBM) to provide a further 200 g CP per day. The contrasting dietary treatments in the three experiments provided intakes of rumen-degradable protein (RDP) ranging from 16 to 388 g/day.

All protein supplements improved overall straw DM intakes, the improvement being significant for U only (P < 0·01). A linear relationship between the daily intake of RDP (g) and straw DM (kg) was obtained. The regression equation was:

DM intake = 5·03 + 0·0035 × RDP (R2 = 0·703; residual s.d. 0·561; d.f. 35; P < 0·001).

All protein supplements also improved the apparent digestibility of straw organic matter (OM) (P < 0·05) and the metabolizable energy (ME) obtained from straw (P < 0·01). Blood urea was increased due to supplementation with urea (P < 0·001), SBM (P < 0·01) and FT-SBM (P < 0·05). Supplementation with BARLEY appeared to improve straw DM intake over MSBP and USBP but this was not reflected in improved ME intake from straw.
Effect of prolonged intermittent water restriction on the reproductive performance of ewes in the Indian desert
Authors: Mittal J. P. , Ghosh P. K.
Published: September 2010

The reproductive performance of female Magra and Marwari sheep of the desert areas of north-western India was studied in relation to intermittent water deprivation, for a period of 39 months during which four breedings were completed. The control group received an ad libitum supply of water every day, while the water-restricted group was provided with water on the same 2 days each week only throughout the experimental period, except during the monsoon season. All the ewes were maintained on cultivated Cenchrus ciliaris pasture. No ill effect was noticed on the general health of the animals. Reproductive measures such as incidence and duration of oestrus, length of the oestrous cycle, conception rate, lambing rate, length of gestation, post-partum interval, inter-lambing period, post-lambing weight of ewes and birth weight of lambs were not significantly affected by the imposed water deprivation. The dailywatered ewes had a slightly, but not significantly higher gain in body weight than the water-restricted ewes. It wa^ concluded that ewes of these two breeds could be maintained on a twice weekly watering schedule for prolonged periods of time without having any adverse effect on their reproductive performance.
A note on dried, molassed sugar-beet pulp and unmolassed, pressed sugar-beet pulp as comparative foods for dairy cows
Authors: Parkins J. J. , Hemingway R. G. , Fraser J.
Published: September 2010

Sugar-beet pulp as normally produced in Great Britain contains about 400 g molasses per kg dry matter (DM). It has been demonstrated that either a reduction in the amount or even the full removal of the molasses did not affect the yield or composition of the milk of cows (e.g. Ronning and Bath, 1962; Hemingway, Parkins and Fraser, 1986). The dried, shredded pulp without molasses was, however, generally less palatable.
The utilization of wilted and unwilted silages by lactating cows and the influence of changes in the protein and energy concentration of the supplement offered
Authors: Gordon F. J. , Peoples A. C.
Published: September 2010

Twenty-four lactating British Friesian cows were used in a four-period partially balanced change-over design experiment to evaluate eight treatments consisting of two silage types (wilted and unwilted), each offered in addition to supplements containing both two crude protein (CP) levels (160 and 210 g/kg fresh weight) and two energy levels (10·8 and 12·9 MJ metabolizable energy (ME) per kg fresh weight) obtained by including 100 g spray-dried tallow per kg, in a 2 × 2 × 2 factorial arrangement. All supplements were offered at ttie same rate of 6·8 kg/day and total diet digestibility and food utilization studies were carried out on all animals at the end of the final period of the experiment. A separate two-period change-over design expeximent, using two lactating cows fitted with rumen cannulae, was undertaken to determine the influence of the two silages on volatile fatty acid (VFA) proportions in the rumen and to measure the rates of disappearance of dry matter (DM) and nitrogen in the silages and supplements from the rumen.

There were no significant interactions between silage and supplement type in terms of animal performance. Animals offered unwilted silage consumed proportionately 003 less DM but produced 0·03 more milk than those offered wilted silage. Although total diet digestibility was not influenced by silage type because of the higher gross energy concentration of the unwilted silage the ME intake with this diet was higher than with the diet based on wilted silage and the ratios of milk energy output to ME available for production (0·54) were similar with both silages. Silage type had no effect on the rumen VFA proportions but influenced the jates of disappearance of DM and nitrogen from the rumen.

Increasing the CP concentratioryof the supplement had no effect on the intake of silage DM but resulted in a significant incrase in milk yield (0·55 kg/day) but due to a reduction in milk fat concentration there was np etfect on yield of either fat-corrected milk or milk energy. The use of the higher energy supplement depressed the intake of silage DM by 0·46 kg/day but resulted in an increase in milk yield of 0·74 kg/day. Neither CP nor energy concentration of the supplement had any effect on DM or energy digestibility of the total diet but there were considerable differences between supplements in the patterns of nitrogen and DM disappearance from the rumen.
In vivo estimation of carcass meat by ultrasound in ram lambs slaughtered at an average live weight of 37 kg
Authors: Fortin A. , Shrestha J. N. B.
Published: September 2010

Ultrasonic measurements of fat thickness and m. longissimus depth 25 and 50 mm lateral to the mid line at the last rib and 100 mm caudally to the last rib were made, before slaughter, on 273 ram lambs using two probes: the Scanogram and Krautkramer. The lambs were from three strains: a meat-type sire strain and two fecund dam strains. They weighed on average 37·3 kg at scanning, (range 29·0 to 51·3 kg), well within the weight range over which Canada Al-grade lambs are marketed in Canada. Their carcasses contained on average 437 g trimmed boneless meat per kg (s.d. pooled within strain = 24·1 g/kg).

The precision with which the ultrasonic measurements combined with live weight at scanning predicted trimmed boneless meat (weight and proportion) was examined. Fat thickness measurements had no predictive value (P > 0·05). The residual standard deviations for the prediction of trimmed boneless meat in the half carcass (weight and proportion) from weight at scanning were 0·29 kg and 21·5 kg, respectively; the addition of the m. longissimus depth measurement reduced the residual standard deviations by 0·02 kg and 1·1 g/kg, respectively. The weight of trimmed boneless meat was predicted with more precision than the proportion of trimmed boneless meat. Strain, location of measurement site or type of instrument did not change the precision of prediction.

It is concluded that prediction of trimmed boneless meat in young ram lambs based on live animal ultrasonic measurements made with the Scanogram or Krautkramer lacks the level of precision necessary for practical application.
The effect of body weight at calving on milk production and reproductive performance of Friesian × Zebu heifers
Authors: Deresz F. , Jaume C. M. , de Carvalho M. R. , González C. A.
Published: September 2010

Twenty-six pregnant Holstein-Friesian × zebu heifers, arranged in pairs according to age, body weight, expected calving date and amount of zebu breeding, were allocated at random to two nutritional regimens during the last 12 weeks before calving. If was planned that the animals in treatment A should calve at a pre-calving live weight of 480 kg and those in treatment B should calve at 380 kg. The diet consisted of maize silage or elephant grass silage, soya-bean meal and minerals. During the first 21 days of the post-partum period both groups were given 6 kg concentrate per head daily. After this period, the feeding level was adjusted every 14 days according to the current milk yield. The mean total milk yields were 2132 kg and 1283 kg (P < 0·05) and the lengths of lactation were 239 days and 156 days (P < 0·01) for cows in treatments A and B, respectively. There was no statistically significant difference between treatments in the intervals from calving to first heat or calving to conception.
Mammogenesis and first lactation milk yields of identical-twin heifers following pre-pubertal administration of bovine growth hormone
Authors: Sandles L. D. , Peel C. J. , Temple-Smith P. D.
Published: September 2010

The effects of long-term administration of bovine growth hormone (GH) on pre-pubertal mammogenesis and subsequent milk production were examined in pasture-fed dairy heifers. Purified bovine GH (specific activity 0·78 i.u. per mg) was administered daily for 21 weeks (0·6 mg GH per kg M 0·75) to one member of each of 12 sets of twins from 3·5 (range 2·5 to 4-5) months of age. GH administration resulted in a significantly smaller mammary gland compared with control heifers at slaughter at the end of treatment (717 v. 839 g; P < 005 (no. = 4)) and increased the proportion of mammary fat pad containing parenchyma (461 v. 383 g/kg; P < 0·01). Mammary parenchymal dry, fat-free tissue was increased in the GH-treated group (25·8 v. 22·5 g; P < 0·05), and fat-pad adipose tissue was reduced (323 v. 435 g; P < 005), compared with the control group. Morphometric analysis of the mammary gland revealed an increase in the volume fraction of connective tissue (P < 0·1) and a tendency toward less fat in GH-treated heifers compared with control heifers. Estimates of the composition of the whole gland confirmed that GH treatment reduced total mammary fat (372 v. 496 g; P < 0·05). At calving, udder volume was greater in the heifers treated with GH compared with the untreated group (14·8 v. 11·2 1; P < 0·05 (no. = 4)). However, there were no differences in the mean daily yields of milk or milk components between groups.
The effects of litter size, sex, age, body weight, dam age and genetic selection for cold resistance on the physiological responses to cold exposure of scottish blackface lambs in a progressively cooled water bath
Authors: Stott A. W. , Slee J.
Published: September 2010

The resistance to body cooling of 594 newborn Scottish Blackface lambs was measured in a water bath during a programme of upwards and downwards genetic selection. Cold resistance was defined as the time taken for rectal temperature to fall to 35°C in the water bath.

Upwards selection produced increased cold resistance which was genetically associated with increased skin thickness, increased total body insulation and greater persistence of high metabolic rate during cold exposure. The first two correlated responses to selection were more pronounced in twins than in singles.

High cold resistance was phenotypically, but not genetically, associated with greater body weight, increased coat depth and higher levels of cold-induced metabolic rate (heat production). Single lambs showed higher weight-adjusted metabolic rates and higher cold resistance than twins. Singles recovered from hypothermia faster than twins in the low selection line only.

Female lambs showed higher metabolic rate (whether weight-adjusted or not) and greater total body insulation than males. Their greater cold resistance was not quite significant. Increasing age (range 0·3 to 36 h) was associated with a small but significant decline in cold resistance.

Thermoneutral metabolic rate was proportional to body surface area, whereas peak metabolic rate was proportional to body weight such that peak metabolic rate per unit body weight was independent of changes in body weight. These findings are discussed in relation to lamb survival.
A note on the rôle of behaviour in pig production and the effect of amperozide on growth performance
Authors: Björk A. K. K. , Olsson N. -G. E. , Martinsson K. B. , Göransson L. A. T.
Published: September 2010

As a result of more intensive rearing and specialization in modern production, pigs are often moved to a new location. In addition, mixing of previously unacquainted pigs usually occurs following transportation to new facilities. Mixing of pigs results in agonistic behaviour (Ewbank, 1976) eliciting social stress (Arnone and Dantzer, 1980) that may produce gastro-intestinal disturbances which adversely affect pig performance.
The effect of additive treatment of grass silage and the food additive avoparcin on the response of calves to supplementation of silage-based diets with fish meal
Authors: Steen R. W. J.
Published: September 2010

Two experiments have been carried out to examine the effects of the fermentation quality of grass silage and the inclusion of avoparcin in the diet on the response in the performance of calves to supplementation of silage-based diets with fish meal. The eight treatments used in each experiment consisted of untreated and formic acid-treated (2·5 1/t) silages offered ad libitum and supplemented with either barley (B) or a barley/fish meal (BF) concentrate (200 g fish meal per kg), without or with 150 mg avoparcin per head daily in a 2 × 2 × 2 factorial design. All animals received 1·25 and 1·0 kg concentrates per head daily in experiments 1 and 2 respectively. In each experiment, the diets were offered to 40 castrated male cattle which were initially 126 and 110 kg live weight in experiments 1 and 2 respectively. On average over the two experiments the untreated and formic acid-treated silages contained 24·8 and 24·5 g nitrogen (N) per kg dry matter (DM); 475 and 571 g protein N per kg total N; 76 and 62 g ammonia-N per kg total N and 45-9 and 27·5 g volatile fatty acids per kg DM respectively. Silage DM intakes for the untreated silages supplemented with B and BF and the acid-treated silages supplemented with B and BF without avoparcin and for the untreated silages supplemented with B and BF and the acid-treated silages supplemented with B and BF with avoparcin were 3·0, 3·2, 3·2, 3·0, 2·9, 3·0, 3·0 and 3·2 (s.e. 0·16) kg/day respectively. Live-weight gains for the corresponding treatments were 0·97, 1·12, 0·98, 1·01, 1·00, 1·07, 1·10 and 1·13 (s.e. 0·032) kg/day respectively. It is concluded that the inclusion of fish meal in diets based on well preserved, grass silage and barley did not affect intake and produced a small response (70 g/day) in the live-weight gain of calves. The inclusion of avoparcin in the diet did not significantly affect the response to fish meal.
Amino acid requirements of the growing meat rabbit 1. The amino acid composition of rabbit whole-body tissue — a theoretical estimate of ideal amino acid balance
Authors: Moughan P. J. , Schultze W. H. , Smith W. C.
Published: September 2010

Whole-body amino acid composition was determined in six male and six female 53-day-old New Zealand White rabbits. There were no significant sex differences in whole-body amino acid compositition except for arginine and glycine where whole-body concentrations (g/16 g N) were significantly lower in the females (P< 0·05). Overall mean whole-body essential amino acid levels (relative to lysine = 100 units) were methionine = 20; cystine = 41; histidine = 50; phenylalanine = 65; tyrosine = 50; threonine = 64; leucine = 112; isoleucine = 51; valine = 62; arginine = 109. The lysine concentration of rabbit whole-body tissue was 6·12 g/16 g N. There was close agreement between rabbit whole-body amino acid composition and corresponding published values for the rat and pig, although the rabbit whole-body cystine was high and methionine concentration low compared with the rat or pig. The rabbit whole-body amino acid pattern can be regarded as approximating an ideal balance of dietary amino acids and as such indicates discrepancies in current recommendations on the essential amino acid requirements for growth in the meat rabbit.
Evaluation of beef breeds for rangeland weaner production in Zimbabwe 1. Productivity of purebred cows
Authors: Tawonezvi H. P. R. , Ward H. K. , Trail J. C. M. , Light D.
Published: September 2010

Purebred cows were evaluated for reproductive performance and live weight, and for pre-weaning growth and viability of crossbred progeny sired by unrelated breeds. The cows comprised three indigenous breeds, Mashona, Nkone and Tuli and four exotic breeds Africander, Brahman, Sussex and Charolais. Over 3 years, the mean calving rates % (s.e.) were 55·5 (3·0), 76·0 (3·8), 63·1 (4·5), 69·6 (3·5), 70·0 (3·8), 60·0 (4·3) and 67·0 (5·0) for Africander, Mashona, Nkone, Tuli, Brahman, Sussex and Charolais cows, respectively.Bos taurusand Brahman cows were heavier at parturition and at calf weaning than indigenous cows. Mashona cows were lightest at both stages. Calves ofBos tauruscows were heaviest at birth and those of Mashona lightest. Calves of Brahman cows had the most rapid growth rate and at weaning (240 days) weighed in kg (s.e.) 207 (3·1), compared with 184 (2·1), 172 (2·2), 187 (2·6), 184 (2·1), 178 (2·7) and 186 (2·9) for progeny of Africander, Mashona, Nkone, Tuli, Sussex and Charolais, respectively. Pre-weaning survival rates of the breeds were not significantly different but viability was higher in progeny of indigenous than exotic breeds. The productivity estimates combining calving rate, cow weight, calf weaning weight and pre-weaning viability demonstrated the superiority of indigenous breeds and the Brahman over Africander andBos taurusbreeds.
A two-pool model of tritiated water kinetics to predict body composition in unfasted lactating goats
Authors: Dunshea F. R. , Bell A. W. , Chandler K. D. , Trigg T. E.
Published: September 2010

A two-pool model of tritiated water kinetics was investigated as a means of partitioning total body water into empty body water and gut water in 17 lactating goats. Empty body water, gut water and total body water were of a similar magnitude to, and highly correlated with, a rapidly equilibrating tritiated water pool, a more slowly equilibrating pool and the sum of these two pools, respectively.

Empty body fat was poorly correlated with both live weight and empty body weight (R2 = 0·42 and 0·51, respectively). However, there was a strong inverse relationship between the water and fat contents of the empty body. Consequently, empty body fat was accurately predicted by a multiple regression equation which included both empty body weight and empty body water as independent variables (R2 = 0·97). Substitution of these variables with estimates derived from tritiated water kinetics still resulted in a high correlation (R2 = 0·88). Tritiated water kinetics offered little improvement over live weight alone in the prediction of empty body protein, empty body ash or fat-free empty body.
A note on the effect of dry season feeding treatment on the subsequent growth at pasture during the wet season of Brahman steers
Authors: Wadsworth J.
Published: September 2010

An experiment was carried out over successive years (1982 and 1983) to measure the extent to which live-weight advantage as a result of feeding in the dry season was maintained during the subsequent wet season at pasture. Two ages of Brahman steer (weaners and yearlings) were kept on three dry season treatments (molasses, sugar cane or grazing only) from January to May and then turned out to pasture as a single group until November. Although the molasses and sugar cane treatments produced significantly higher live-weight gains during the dry season the resultant weight advantage at turn-out was largely reduced during the wet season due to compensatory growth exhibited by previously restricted animals. Yearlings were less able to compensate than weaners.
The value of cloning in MOET nucleus breeding schemes for dairy cattle
Authors: Woolliams J. A.
Published: September 2010

The value of cloning in MOET nucleus breeding schemes has to be considered within the constraint of fixed resources. Under this constraint cloning was found to add to genetic progress only when (i) the heritability is low and (ii) it is used at the expense of a reduction in the number of bull families. This course would exacerbate inbreeding and other potential problems with MOET. All other options for using clones lead to a reduction in genetic progress due to a loss of selection intensity that is not made up for by gains in selection accuracy.
A note on the effects of nutrient intake during the later stages of rearing and early reproductive life on the subsequent reproductive efficiency of gilts
Authors: King R. H.
Published: September 2010

Seventy-eight gilts in replicates of three litter-mates were allocated at 135 days of age and 65·4 kg live weight among three treatments. Between allocation and mating gilts were given either 1·78 kg/day (LL) or 2·72 kg/day (LH) diet containing 12·3 MJ digestible energy (DE) per kg and 5·3 g lysine per kg or 2·57 kg/day (HH) diet containing 12·6 MJ DE per kg and 8·1 g lysine per kg. More gilts in the LH and HH groups attained puberty within 200 days of age than LL gilts (41/52 v. 72/26, X2 = 8·9, P < 0·01). Live weight at conception was 93·8, 105·3 and 108·9 kg for LL, LH and HH gilts respectively at a mean age of 203 days. Subsequent reproductive efficiency and sow body weight and backfat changes were not significantly affected by treatments imposed during the early stages of reproductive life.
Water-washed neem (azadirachta indica) seed kernel cake in the feeding of milch cows
Authors: Nath K. , Agrawal D. K. , Hasan Q. Z. , Daniel S. J. , Sastry V. R. B.
Published: September 2010

A full lactation (300 days) experiment on 32 crossbred milch cows, separated into two groups was carried out. Group 1 (control) was given a concentrate mixture consisting of 400 g groundnut cake, 300 g crushed maize, 270 g wheat bran, 20 g mineral mixture and 10 g common salt per kg; while in group 2 (experimental) the groundnut cake was replaced by water-washed neem seed kernel cake (WWNSKC). Roughage was common in both the groups. Digestion and balance study on nine cows in group 1 and eight in group 2 was carried out after 3 months experimental feeding. Milk yield was recorded twice daily and butter fat, protein and total solids were determined every month in the milk of each animal. The results showed that there was no significant difference (P > 0·05) in the milk yield, butter fat content, organoleptic evaluation of milk, dry-matter intake, digestibility of nutrients, haemoglobin, SGOT, SGPT, acid phosphatase and alkaline phosphatase in blood and reproductive ability of the cows in the two groups. The nitrogen balance was higher in the WWNSKC group (P < 0·05) due mainly to less excretion of urinary nitrogen and a concomitent decrease in blood urea nitrogen. It is concluded that water washing of neem seed kernel cake, whose potential availability in India alone is about 0·9 Mt annually, can convert this cake, hitherto going waste, into an excellent high protein animal food and can be used for feeding milch animals without any adverse effect. It is recommended that this technology be adopted by all neem seed-cake producing countries, specially those developing countries having chronic shortage of foods and fodders for animal feeding.
Cottonseed for protein and energy supplementation of high-roughage diets for beef cattle
Authors: Brosh A. , Holzer Z. , Levy D.
Published: September 2010

The use of cottonseed (CS) as an energy and protein supplement to high wheat-straw diets was studied in a digestion and nitrogen balance trial, and as a component in fattening diets in a feeding trial. The proportions of CS studied were 0, 60, 120, 180 and 240 g/kg diet dry matter (DM). DM intake per kg M0·75 was 33, 31, 40, 31 and 29 g, respectively. The digestibility coefficient of organic matter was 415, 463, 417, 441, 350 g/kg DM and of neutral-detergent fibre was 350, 436, 411, 309, 334 g/kg DM. Nitrogen balance was –2·52, 1·1, 5·38, 5·63, 7·60 g/day respectively, for the same order of treatments. The effect of high proportions of CS in the diet in restricting DM intake and reducing its digestibility was evident. The results of the feeding trial were in agreement with those of the digestion trial and indicate the proportion of 120 g CS per kg DM as optimal and maximal.
Rumen degradation of straw. 8. Effect of alkaline hydrogen peroxide on degradation of straw using either sodium hydroxide or gaseous ammonia as source of alkali
Authors: Adebowale E. A. , Ørskov E. R. , Hotten P. M.
Published: September 2010

The comparative effect of spraying wheat straw, maize stover and maize cob with sodium hydroxide and alkaline (sodium hydroxide treated) hydrogen peroxide over a range of moisture contents was evaluated. The effect of concentration of hydrogen peroxide on straw subsequently ammoniated was also investigated. No differences (P < 0·05) were detected between sodium hydroxide and similar concentrations of sodium hydroxide used to provide alkali for alkaline hydrogen peroxide treatments. When however, gaseous ammonia was used as the source of alkali there were significant linear increases in degradability with increasing concentrations of hydrogen peroxide. At 48 h incubation, degradability values for untreated, ammonia-treated, 10, 50 and 100 g alkaline (ammonia) hydrogen peroxide per kg were 528, 595, 640, 676 and 716 for wheat straw, 618, 652, 683, 717 and 743 for maize stover and 392, 467, 585, 632 and 686 g/kg for maize cob respectively. It is concluded that the use of gaseous ammonia as the source of alkali seems a possible practical method of using hydrogen peroxide to increase degradability of straws.
Environmental modifications in a pig growth model for early-weaned piglets
Authors: Jacobson L. D. , Cornelius S. G. , Jordan K. A.
Published: September 2010

A food-driven pig growth model was developed from two existing mathematical models. The new model predicts daily growth and heat production of early-weaned pigs. An existing pig growth model was altered by replacing the environmental component with a heat transfer model. The heat transfer model was further refined by partitioning latent heat loss between the skin and lungs, adding a thermal resistance for hair coat, and increasing tissue thermal resistance. Results from this combined model were compared with experimental observations of daily piglet growth and heat production at 15°C, 20°C, 25°C and 30°C. Good agreement existed between observed data and model predictions for piglet growth. Heat production predictions did not compare as well with experimental observations as did growth, especially when piglets lost weight.
Pituitary responses of seasonally anoestrous ewes to long-term continuous infusion of low doses of GnRH
Authors: Khalid M. , Haresign W. , Hunter M. G. , McLeod B. J.
Published: September 2010

The response to long-term continuous infusion of gonadotrophin releasing hormone(GnRH)was monitored in progesterone-treated seasonally anoestrous ewes. Using osmotic pumps, groups of five ewes eachreceived 0(controls),125, 250, 500 or 1000 ng GnRH per h subcutaneously for a period of 21 days. Bloodsamples were collecte dat 30-minintervals from 6 h before until 24 h after the start of treatment and then for 8-h periods on days 2, 8, 15 and 21. After 21 days of treatment all the ewes were slaughtered to determine pituitary GnRH receptor numbers. Continuous infusion of GnRH resulted in a short-lived (2day)increase in plasma LH and oestradiol concentrations after which they were not different from the pre-treatment values. Over the later period of treatment when the pituitary gland was not responding to the exogenous GnRH(days 8, 15 and 21), LH episodes(presumably due to endogenous GnRH secretion fromthe hypothalamus) were observed. Continuous infusion of GnRH was also associated with a suppression in plasma FSH concentrations, the duration of which was dose-dependent. Only at the highest GnRH dose level(1000 ng/h)was there a significant reductionin pituitary GnRH receptor content.
A note on the influence of an acidified liquid sow-milk replacer on the performance of sucking and early-weaned piglets
Authors: Ellis M. , Rowlinson P.
Published: September 2010

Litters of piglets were given ad libitum access to a sow-milk replacer (SMR) during lactation (200 g SMR per I) and the 1st week after weaning (100 g SMR per I). Weaning was at 3 and 4 weeks of age in the first and second studies respectively. SMR was readily consumed but was associated with a high incidence of scouring, reduced intakes of creep food, and (in one study) increased mortality. There was a trend towards increased litter weight in the 4-week weaning study only.
Effects of cimaterol on energy utilization for maintenance and for protein and fat deposition by wether and ewe lambs given chopped lucerne hay or lucerne-barley pellets
Authors: Sainz R. D. , Wolff J. E. , Upsdell M. P.
Published: September 2010

The effects of sex (wethersv.ewes), diet (chopped lucerne hayv.lucerne-barley pellets) and cimaterol on energy utilization by Suffolk cross lambs were determined by comparative slaughter. Quadratic regression of energy retention (RE) on metabolizable energy intake (MEI) enabled estimation of maintenance energy requirements (Em), efficiencies of gain (ktotal) and maximum rates of gain (REMAX). Regressions using RE in fat and proteinv.MEI yielded analogous parameters for fat and protein deposition (Em fat, kfat, REMAX fatand Emprotcin, kprolein, REMAXprotcinrespectively). Emwas lower in wethers than ewes (455v.510 kJ/kg M0·75per day respectively), but was unaffected by diet or cimaterol. Sex and cimaterol did not affect ktotai. which was higher in lambs given pellets compared with lambs given hay (0·417v.0·224 respectively). Similarly, REMAXwas higher in lambs given pellets than in lambs given hay (326v.114 kJ/kg 0·75 per day respectively). None of the groups differed significantly in the parameters of fat deposition, which averaged 480 kJ/kg 0·75 per day for Emfal, 0·224 for ktat, and 250 kJ/kg M0·75per day for REMAX, fat-Em.proteinwas lower in wethers than in ewes (466v.569 kJ/kg 0·075 per day, respectively), and was further reduced by cimaterol (418 and 507 kJ/kg 0·75 per day for wethers and ewes respectively). Estimates of kprotcin were higher in wethers than in ewes (0·091v.0·064 respectively), and were increased by cimaterol (0·115 and 0·089 for wethers and ewes respectively). Similarly REMAX protein was higher in wethers than in ewes (47v.37 kJ/kg 0·75 per day respectively), and was increased by cimaterol (58 and 48 kJ/kg 0·75 per day for wethers and ewes respectively). The repartitioning action of cimaterol was additive with effects of diet, intake and sex.
Comparison of Duroc and British Landrace pigs and the estimation of genetic and phenotypic parameters for growth and carcass traits
Authors: Cameron N. D.
Published: September 2010

Duroc and halothane negative British Landrace boars and gilts were performance tested on ad libitum or restricted feeding regimes, with like-sexed non-littermate groups of one, two, three or four pigs per pen. There was a total of 320 pigs with 20 litter groups per breed with four boars and four gilts per litter group. Within each feeding regime, a boar and a gilt from each litter were tested on one of two diets in 1986, for each of the four combinations, and pigs were tested similarly for two other diets in 1987. Carcass composition was determined by half-carcass dissection of 160 pigs allocated between treatments.

There was a breed × sex interaction for growth and performance traits for pigs fed ad libitum. Duroc boars were faster growing and more efficient than Landrace boars, but Duroc gilts grew more slowly and were less efficient than Landrace gilts. On restricted feeding, Duroc pigs were more efficient than Landrace pigs.

At constant slaughter weight, Duroc pigs had less subcutaneous fat but more intermuscular fat. Although they had less separable fat in the carcass, Duroc pigs were not leaner as weights of bone, skin, head, feet and tail were heavier than for Landrace pigs.

Group penning and group feeding of pigs may have enhanced competition effects resulting in positive genetic and phenotypic correlations between growth rate and backfat depths on both feeding regimes.

The positive genetic correlation between growth rate and fat deposition resulted in a negative genetic correlation between growth rate and carcass lean content and a lower genetic correlation with lean tissue growth rate than in other studies.
A note on the response of growing pigs to supplemental biotin
Authors: Partridge I. G. , McDonald M. S.
Published: September 2010

The response of pigs to supplemental biotin (500 μg/kg diet) was studied in a growth trial from 15 to 88 kg live weight. Food: gain ratio was significantly improved during the grower phase and there was a tendency for improvement in the starter and finisher phases. There was also a tendency towards improved carcass grading.
Efficiency of nucleus breeding schemes in dual-purpose cattle of Tanzania
Authors: Kasonta J. S. , Nitter G.
Published: September 2010

For the Mpwapwa cattle breed in Tanzania, the efficiency of various breeding schemes including an open nucleus was investigated by model calculations. Artificial insemination and intensive recording of production are assumed to be applied in a nucleus which is the main breeding unit. As a pre-nucleus, associated herds with less intense data recording serve as the basis to screen superior cows for nucleus replacements, provide the capacity for progeny testing, and operate as bull multipliers for commercial herds.

The criteria of efficiency were genetic gain and profit from selection for a dual purpose breeding objective (milk and beef) in a total population of 10 000 cows. Introducing a two breeding tier scheme through separating all recorded cows into a nucleus and pre-nucleus leads to an increase of the genetic gain rather than the profit. Further improvement is obtained by introduction of artificial insemination in pre-nucleus herds. The nucleus size should not exceed about 5% of the cow population and an optimum size of the pre-nucleus is about 15%. Opening the nucleus to replacement cows coming from the pre-nucleus affects the aggregate genetic gain very little although it can be recommended if milk yield is to be mainly improved or if the total profit is taken into account. Furthermore, the nucleus should be opened if there is little difference between the heritabilities in the nucleus and pre-nucleus and also in order to avoid detrimental effects of inbreeding and genotype × environment interaction.