Twenty-five primigravid ewes were used in a preliminary study to investigate the effect of bovine somatotropin (bST) between 97 and 124 days of gestation, on maternaland foetal growthand development. Five ewes (reference group) were slaughteredat 96 days of gestation, and the remaining ewes were injected daily with saline (control group: no = 10) or 0·1 mg/kgbody weight of bST (bST group: no. = 10). Following bST treatment, five control- and five bST groupewes were slaughtered (slaughter group). The remaining ewes (production group) were allowed to lamb, after which the lambs were slaughtered within 2 h of birth. Bovine somatotropin reducedthe proportion of maternal body fat, but had no major impacton wool growth, maternal gain and gross skeletal measurements, and foetal growth and development. Maternal bST treatment tended to affect the number of placentomes. It should, however, be emphasized that these results are based on small numbers of animals and that further research in this area is required.

Triptorelin (TRI), a gonadotropin-releasing hormone agonist allowing ovulation synchronization in pigs, is indispensable for fixed-time artificial insemination (FTAI) protocols. However, the effect of FTAI using TRI (FTAI-TRI) on the reproductive performance is controversial. We performed a meta-analysis to determine whether FTAI-TRI affects reproductive performance of pigs, including pregnancy rate (PR), number of pigs born alive per litter (NBA), farrowing rate (FR) and total number of pigs born per litter (TNB). A total of 37 trials from 15 studies were extracted and analysed in Stata. A weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for NBA and TNB, and risk ratio (RR) with 95% CI was calculated for PR and FR. Pregnancy rate, TNB and NBA data were applied to a fixed-effect protocol, and FR data were applied to a random-effect protocol. We found that for weaned sows, the FTAI-TRI group had comparable reproductive performance to the artificial insemination (AI) following oestrus detection (EDAI) group. Fixed-time AI has many advantages, including the elimination of the need to heat-check twice daily, so that FTAI-TRI is a good substitute for EDAI. Subgroup analysis indicated that the optimal timing of triptorelin treatment was 96 h after weaning, which gave significant positive effects on PR (RR = 1.08, P = 0.000) and non-significant positive effects on TNB (WMD = 0.12, P = 0.452). Triptorelin at a dose of 100 μg showed better effects than 200 μg, with significant positive effects on PR (RR = 1.09, P = 0.005) and FR (RR = 1.06, P = 0.036). So a single dose of 100 μg was recommended. The optimal protocol was insemination at 24 h and again at 48 h after triptorelin administration if they remained in standing oestrus, and this provided a significantly higher NBA (WMD = 0.59, P = 0.013) that increased by 0.59. For gilts, the FTAI-TRI group showed decreased (not significant) PR (RR = 0.96, P = 0.127) and significantly decreased FR (RR = 0.93, P = 0.013), TNB (WMD = −0.85, P = 0.006) and NBA (WMD = −0.98, P = 0.000), which were inferior to those in the EDAI group. In conclusion, the effects of FTAI-TRI on the reproductive performance of pigs were parity-, treatment timing-, insemination timing-, and dosage-dependent. Fixed-time AI using triptorelin could effectively replace the EDAI protocol for sows, but not for gilts.

In the middle of the 20th century, increasing inbreeding rates were identified as a threat to livestock breeding. Consequences include reduced fertility, fitness and phenotypic expression of lethal alleles. An important step in mitigating this inbreeding was the introduction of optimum contribution selection (OCS). OCS facilitates the simultaneous management of genetic gain and inbreeding rates. However, using a standard OCS methodology for regional breeds with historical introgression for upgrading reasons could lead to reinforced selection on introgressed genetic material since those alleles improve the rate of genetic gain and reduce the average kinship in the population. Consequently, regional breeds may become genetically extinct if a standard OCS approach is used. Thus, the advanced OCS (aOCS) approach takes introgressed genetic material into account. The major goals of this study were to (i) gather key information on the feasibility of aOCS under practical conditions of the actual breeding scheme of Vorderwald cattle, (ii) identify superior strategies for implementing the actual scheme and (iii) examine whether historical breeding decisions to increase genetic gain by introgression from commercial breeds could have been avoided by using aOCS. Stochastic simulations were designed in this study to create populations from the historical gene pool by using aOCS. Simultaneously, all practical constraints of a breeding scheme were met. Thus, the simulated populations were comparable with real data. The annual genetic gain was higher in reality (1.56) than in the simulation scenarios (1.12–1.40). The introgressed genetic material increased to 61.3% in reality but was conserved at a final value of 15.3% (±0.78) across simulations. The classical rate of inbreeding and rate of native inbreeding were constrained to 0.092% on an annual basis. This value is equal to an effective population size of 100. The observed values for rates of inbreeding were 0.082–0.087% and 0.087–0.088% for classical and native kinship, respectively. The corresponding figures in reality were 0.067% and 0.184%, respectively. This study suggests that aOCS is feasible for Vorderwald cattle. Strategies for implementation are identified. Finally, we conclude that historical breeding decisions could have been avoided by using aOCS. The genetic gain would have been reduced by at least 12.2%, but the introgressed genetic material, genetic diversity and native genetic diversity would have been more desirable for a breed under conservation.

The effect of haemoglobin types A and B on reproductive performance of ewes grazing oestrogenic pastures was studied in four commercial flocks in 1973 and in an additional five in 1974 (a total of nine flocks). The number of ewes lambing per ewe mated differed significantly (P< 0·05) between mating types (male AA × female AA, male AA × female AB, male BB × female AB and male BB × female BB). Differences between mating types in the number of lambs born per ewe exposed to the ram and in the number of lambs weaned per ewe exposed to the ram bordered on significance (0·05<P<0·1). Matings involving BB sires were superior to matings involving AA sires. This finding differs from previously published evidence on this topic. There were no significant differences in lamb mortality or in the number of lambs born per parturition. Reproductive performance did not differ amongst ewe genotypes. Age of dam, farm and year had significant effects on most of the reproductive characteristics studied. Three significant interactions (P<0·05) involving mating type were found: mating type × age on number of ewes lambing per ewe exposed to the ram, mating type × farm on number of lambs born per parturition and mating type × year on lamb mortality. Due to the relatively small differences observed in reproductive performance between mating types it is concluded that selection for haemoglobin type is unlikely to overcome the problem of low reproductive performance in sheep grazing oestrogenic pastures.

The distribution of intermuscular fat (IF) was studied in 24 lambs, of balanced sexes, from each of the Dorset Horn, Hampshire and Clun breeds, which were slaughtered at 42 kg live weight. The Clun lambs yielded the least total IF, the Dorset Horn most and the Hampshire an intermediate amount. The Clun lambs had significantly (P<005) less IF in the thoracic limb than the other two breeds; and the IF content of the neck+thorax region in the Hampshire was lower than that in the remaining breeds. Females had more IF than males in all sites examined. At an equally adjusted total IF weight, sex differences disappeared. The Hampshire yielded more IF in the thoracic limb, pelvic limb and back+abdomen, but, exceptionally, less IF in the neck + thorax than in the other two breeds.

The Ram Genotyping Scheme was launched in Great Britain in 2001 as part of the National Scrapie Plan and was devised to reduce and eventually eradicate classical scrapie susceptible genotypes from the national pedigree flock. Anecdotal claims from breeders suggest that sheep with more resistant PrP genotypes may have inferior phenotypes. In this study, we test this possibility for lamb production traits in three breeds of lowland sheep: Charollais (22 752 lambs), Poll Dorset (22 589 lambs) and Texel (23 492 lambs). Data were received from 50 breeders and comprised weights at birth, 8 weeks and scanning (from which average daily weight gain was derived), and ultrasonic muscle and fat depths. Animal (direct) genetic effects and up to three maternal effects were fitted in linear mixed models for each trait. Fitting either PrP genotype or number of copies of individual alleles carried as fixed effects allowed potential associations with the PrP gene to be assessed. There were no significant associations seen in the Poll Dorset breed; however, significant associations were found with the number of allele copies carried in the other two breeds included in this study. Charollais lambs carrying one copy of the VRQ allele had significantly (P < 0.01) greater ultrasonic muscle depth (0.58 mm) and fat depth (0.2 mm) than non-carriers. In the Texel breed, lambs with one ARR allele were significantly heavier than those with two or zero ARR alleles; heterozygous ARR lambs were 0.07 kg heavier at birth (P < 0.05), 0.42 kg heavier at 8 weeks (P < 0.01) and 0.17 kg heavier at scan weight (P < 0.01), than non-carriers. After Bonferroni corrections to adjust significance thresholds to account for the large number of independent comparisons made, all significant results remained so at P < 0.05 or greater, except for the ARR allele effect on birth weight in the Texel breed, which was no longer significant. These results compare favourably with others from studies on many continental breeds of sheep, published in recent years, and add credence to the conclusion that selection on PrP genotype is unlikely to have any noticeable impact on the measured growth and carcass traits in sheep.

Modern research makes frequent use of animal models, that is, organisms raised and bred experimentally in order to help the understanding of biological and chemical processes affecting organisms or whole environments. The development of flexible, reprogrammable and modular systems that may help the automatic production of ‘not-easy-to-keep’ species is important for scientific purposes and for such aquaculture needs as the production of alive foods, the culture of small larvae and the test of new culture procedures. For this reason, we planned and built a programmable experimental system adaptable to the culture of various aquatic organisms, at different developmental stages. The system is based on culture cylinders contained into operational tanks connected to water conditioning tanks. A programmable central processor unit controls the operations, that is, water changes, temperature, light irradiance, the opening and closure of valves for the discharge of unused foods, water circulation and filtration and disinfection systems, according to the information received by various probes. Various devices may be set to modify water circulation and water changes to fulfil the needs of given organisms, to avoid damage of delicate structures, improve feeding performances and reduce the risk of movements over the water surface. The results obtained indicate that the system is effective in the production of shrimp larvae, being able to produce Hippolyte inermis post-larvae with low mortality as compared with the standard operation procedures followed by human operators. Therefore, the patented prototype described in the present study is a possible solution to automate and simplify the rearing of small invertebrates in the laboratory and in production plants.

A study was conducted to examine the effect of fine grinding or sodium hydroxide treatment of wheat, and increasing concentrate food level, on milk production. Two concentrates based either on ground wheat (450 g/kg, GW) or sodium hydroxide treated wheat (500 g/kg, SW) were offered at four concentrate levels of 2·5, 5·0, 7·5 and 10·0 kg dry matter (DM) per day to 24 dairy cows in a three-period, change-over design experiment. On average, across all concentrate food levels, silage DM intake was significantly (P < 0·01) higher with the SW concentrates, reflecting a significantly lower silage substitution rate with SW relative to GW concentrates (P < 0·01). Milk yield was also significantly higher with the SW concentrates (P < 0·05), although marginal responses to increased concentrate food level were similar (P > 0·05). Milk protein concentration increased linearly with increasing concentrate food level (P < 0·001), with a significantly greater response with the GW relative to the SW concentrate (0·59 v. 0·24 g/kg (P < 0·05) increase per kg additional concentrate). However, milk protein concentration was also significantly lower with the GW concentrate at low food levels (P < 0·05). Milk fat concentrations were similar with the two concentrate types with significant reductions in milk fat concentration with increasing concentrate food level (P < 0·05). Blood urea (P < 0·001) and β-hydroxybutyrate (P < 0·05) concentrations were significantly lower in animals offered the SW concentrate. Apparent digestibility coefficients were unaffected by either concentrate type or concentrate food level (P > 0·05), although modified acid-detergent fibre apparent digestibility was significantly reduced with increasing concentrate food level (P < 0·001). Results indicate that, at similar levels of concentrate feeding, silage intake and milk yield were significantly greater with SW compared with GW concentrates (P < 0·05 or greater). Increases in milk protein concentration with increasing concentrate food level were significantly greater with GW than with SW concentrates (P < 0·05).

A total of 63 primiparous hybrid sows were used in two experiments to study the effect of different fat and α-tocopherol levels in the lactation diet on the performance and milk production of sows and on the performance of sucking piglets. In experiment 1, the major differences in energy sources in the lactation diets were tapioca starch or animal fat. Fifteen sows received the low-fat diet (starch and fat content: 396 and 43 g/kg dry matter (DM)) and 16 sows were given the moderate-fat diet (starch and fat content: 286 and 75 g/kg DM) during 4 weeks of lactation. In experiment 2,16 sows were given a low-fat diet (diet 1: starch and fat content: 418 and 37 g/kg DM) and 16 were given a high-fat diet (diet 2: starch and fat content: 266 and 125 g/kg DM) during 4 weeks of lactation. In diet 2, 68 g animal fat replaced the 200 g starch present in diet 1. The mean α-tocopherol contents of foods in experiment 1 were 14 and 126 mg/kg diet and in experiment 2, 22 and 151 mg/kg diet. The live weight, backfat thickness and milk production of sows were not significantly affected by the different dietary fat levels (P > 0·05). The high dietary fat level increased the DM, fat and energy content of milk and the daily gain of piglets in the second part of lactation in experiment 2 (P < 0·05). The correlation between piglet growth and milk fat and milk energy intake (r) in experiment 1 were: 0·57 and 0·66 and in experiment 2 were 0·41 and 0·40 respectively. The utilization of whole milk and DM, fat, protein and energy content of milk for piglet growth was not influenced by dietary fat level. Varying the level of dietary α-tocopherol did not affect the variables investigated.

The effects of the inclusion of increasing quantities of cereal straw treated with sodium hydroxide in the diet of rabbits weie studied on 68 animals, both males and females, of the Spanish Giant and New Zealand × Spanish Giant breeds, weaned at different weights. The nitrogen and fibre digestibilities, the overall growth rate (from weaning to 2·25 kg) and the partial growth rate (from weaning to 2 weeks after weaning) increased linearly, while the feed conversion rate decreased when the content of treated straw in the feed was raised. The overall growth rate for males was significantly higher (P < 0·001) and feed conversion rate lower (P < 0·01) than for females. The crossbred animals had a significantly higher overall (P < 0·001) and partial (P < 0·05) growth rate. As weaning weight increased, overall (P < 0·001) and partial (P < 0·05) growth rate also increased, whereas the dressing percentage of the carcass decreased significantly (P < 0·01).

The influence of feeds containing varying dietary cation–anion differences (DCADs) with and without supplements of 25-hydroxyvitamin D (25(OH)D) on urine pH and excretion of macro minerals was determined in fistulated crossbred steers (mean live weight 315 ± 45 kg). A basal forage diet comprising lucerne hay and wheat chaff was used, to which varying quantities of MgCl2 or K2CO3 were added to achieve four levels of DCAD: −300, 50, 150 or 250 mEq/kg dry matter (DM). Steers were allocated to one of six treatments, one treatment for each diet and a further treatment for both the 50 and 150 mEq/kg DCAD diets, which were supplemented with 25(OH)D at a rate of 3 mg/steer per day. Urine pH from steers offered the diets comprising DCADs of 50, 150 and 250 mEq/kg ranging from 8.3 to 8.8. In treatments not containing 25(OH)D with DCADs of 50 to 250 mEq/kg, there were no significant differences in urine pH or Ca excretion. However, steers offered the diet with a DCAD of −300 mEq/kg DM produced urine with a significantly lower pH (6.5 to 7.5). Daily output of Ca in urine was also significantly higher from steers given this diet. Supplementation with 25(OH)D significantly increased urinary Ca excretion from steers offered diets of DCADs 50 and 150 mEq/kg DM. Estimates of daily urinary Ca excretion, calculated using the ratio of creatinine to Ca in ‘spot’ urine samples, were less variable than those based on total collection (residual mean square of 0.54 and 0.63, respectively).

Carcass measurements made on 1,463 Large White pigs from 88 inbred lines, at various degrees of inbreeding, have been analysed.

Partial regression coefficients calculated within lines showed that each 10% increase in inbreeding coefficient significantly increased carcass weight by 0·46 lb., decreased mid-back fat thickness by 0·37 mm. and streak thickness by 0·36 mm.

Partial regression coefficients calculated on all the material, or on line means showed, however, that the most highly inbred pigs tended to be shorter and fatter than average. Possible explanations of this finding are discussed and it is suggested that under the selection procedure adopted for litter size and weaning, weight favours the survival of these less desirable lines.

The pattern of growth and carcass composition of indigenous Ethiopian fat-tailed Menz and Horro lambs were assessed through serial slaughter and carcass dissection of 147 lambs at five different growth phases. The GLM procedure of Statistical Analysis Systems Institute and allometric growth equations were used to assess the effects of various factors and differential growth of carcass components, respectively. Results showed that the growth and carcass composition of Menz and Horro lambs was significantly (P < 0.05 to P < 0.001) affected by the genotype, growth phase and season of birth of lambs. The effects of growth phase clearly showed that slower growth of the body and of carcass components was observed during the third phase (i.e. after weaning). Although there was an effect on fat to lean ratios (P < 0.05), growth phase had no significant effect on dressing out proportion, and lean to bone ratios. A significant influence of genotype (P < 0.001) and sex (P < 0.05) on lean to bone ratios indicated that the Horro sheep and ram lambs had a much more developed and heavier skeleton than the Menz sheep and ewe lambs. Higher pre-slaughter, hot carcass, lean and bone and fat weights of May/June born lambs revealed significant advantages of wet season lambing for fast growth and improved carcass composition. The log/log regression of weights of dissectible carcass components on hot carcass and empty body weight showed that the differential growth of bone was declining and that of lean was isometric relative to the growth of empty body weight. For carcass fat, the allometric growth coefficients (b) of 1.5 and 1.8 for Menz and Horro sheep, respectively indicated that fat is a late maturing body component. Moreover the growth of carcass fat relative to empty body weight in the Menz and Horro sheep is slower than that reported for tropical sheep breeds.

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 economic value of the goat depends upon its growth and reproductive and productive efficiency. The growth determines the meat producing ability up to a marketable age i.e. 6 months. Rapid growth during the pre-weaning period minimizes the cost of rearing, thus providing more profit to the farmer. The present investigation reports the effect of genetic groups, years and season of birth, sex of kid, type of birth and dam's weight at kidding on pre-weaning growth traits, and the extent of the genetic variability and covariability among these traits.

Body length has long been emphasized by the Scandinavian breeders as being of paramount economic importance in the selection of pigs for the British market. (Rozycki; Jespersen and Madsen ; cited by Smith and Robison, 1934). The development of strains or breeds of pigs possessing some uniformity regarding body length may well assist materially in producing at home the type of bacon which the British housewife needs instead of the continued importation of such bacon from those countries which have for so long dominated our markets. The difficulty of assessing in the live pig what its carcass grade will be, or of forecasting in the weaner its potential quality as a baconer, calls for scientific investigation into the ways and means of doing this, particularly for the selection of pigs for breeding and improvement policies.

Adding corn silage (CS) instead of alfalfa hay (AH) to the finely ground starter diet would improve calf performance if feed intake or feed efficiency is increased. We investigated the effects of replacing AH with CS in the starter diet on nutrient intake, digestibility, growth performance, rumen fermentation and selected blood metabolites in Holstein calves. Newborn male calves (n = 30; 3 days of age; 40.2 ± 1.28 kg BW) were assigned randomly to three groups receiving starter diets containing chopped AH (10% dry matter (DM) basis; AH diet), CS (10% DM, CS diet) or their combination (each at 5% level; AHCS diet). The starter diets had the same nutrient composition but differed in DM content (91.2%, 87.5% and 83.8% for AH, AHCS and CS, respectively). The calves were weaned on day 50, and the study continued until day 70. Nutrient intake, BW (at weaning and at the end of the study) and body measurements were not affected by the diet. During the post-weaning period, average daily gain tended to be greater on CS than on AH diet. Feed efficiency was greater in CS than in AH or AHCS calves during the post-weaning period. Digestibility of neutral detergent fiber was greater in AHCS and CS compared with AH during the post-weaning period. Concentration and profile of volatile fatty acids and ruminal fluid pH were not affected by the diet. Replacing AH with CS in the starter diet had no effect on feed intake, growth performance and general health of the calves. These results indicate that AH and CS can be used interchangeably in dairy calf starter diets until 70 days of age, allowing dairy producers more choices in selecting the feed ingredients.

The study determined the effects of partial removal of alkaloids (detoxification) in crushed lupin seed (CLS) on voluntary food intake, and yield and composition of milk from dairy cattle. Twenty multiparous Friesian dairy cows (first 90 days of lactation) were assigned, according to a randomized complete-block design, to five diets. The diets were formulated to be isonitrogenous (25·6 g N per kg of diet dry matter (DM)) and contained napier grass, lucerne hay, maize bran and urea. The control diet (CON) contained sunflower meal; two diets contained intact CLS at 150 (LUI-15) or 300 g (LUl-30) per kg diet DM. The other two diets contained detoxified CLS at 150 (LUD-15) or 300 g (LUD-30) per kg diet DM. Lupin seeds were detoxified by treatment with boiling water, followed by steeping in cold water. The diets were analysed by gas chromatography for the alkaloids, lupanine and 13-hydroxylupanine. The total alkaloid content of LUI-15 and LUl-30 was 3·8 and 8·0 g/kg diet DM, respectively; by contrast that of LUD-15 and LUD-30 was 2·1 and 5·2 g/kg diet DM respectively. Increasing the level of intact CLS in the diet led to a decrease in voluntary food intake. Cows given LUl-30 had a lower milk yield (11·1 kg/day) than those given LUI-15 (13·8 kg/day; P < 0·01) but there was no difference in either milk protein yield or content. Detoxification of lupin removed proportionately about 0·40 of the total alkaloids from intact CLS and increased food intake, and the yield of milk and milk protein (P < 0·05) but reduced milk fat content. Detoxification of CLS also reduced the rumen degradability of lupin protein (P< 0·05). It is concluded that the reduction in organic matter intake and milk yield of cows given diets containing intact CLS was due to the presence of lupanine and 13-hydroxylupanine. To maximize its usage in diets for dairy cattle, lupin should be detoxified; it can then be included at levels up to 300 g/kg diet DM.

The effects of fertilization (100 kg nitrogen plus 10kg phosphorus per ha per year) of Cymbopogon-Themeda veld on certain chemical components in vitro dry-matter digestibility (IVDMD), intake by either lactating cows or steers as well as daily gain of pre-weaned calves or steers, were determined in the summer rainfall area of the Republic of South Africa.

The nutritive value of fertilized veld herbage was, in terms of crude protein and acid-detergent fibre content, IVDMD and herbage intake, superior to that of unfertilized veld. Species, classified as palatable according to the literature, were more abundant on the fertilized veld than on the unfertilized veld. In spite of the fact that the stocking rate on the fertilized veld was double that of the unfertilized veld, the average daily gain (ADG) of steers on the former was higher than that of steers on the latter. There was no significant difference in the ADG of the pre-weaned calves, whose dams grazed either fertilized or unfertilized veld. It was calculated that the fertilization of veld for growing steers can (under the conditions that prevailed) be a financially viable proposition if the beef price per kg live weight amounts to at least 0·65% of the cost of fertilization per ha.

Data from 1447 pigs from 438 litters were used to estimate heritability, breeding and mating system differences and heterosis of atrophic rhinitis. Yorkshire, Landrace and Lacombe breeds and their crosses were represented. Rhinitis was measured by necropsic examination of the degree of degeneration of the nasal turbinates. Two traits were considered: rhinitis incidence, based on whether or not pigs showed any nasal turbinate degeneration; and rhinitis score, which ranged from zero to four, based on the percentage of nasal turbinate degeneration exhibited. Heritabilities of rhinitis incidence and score were 0·12±0·09 and 0·03±0·02, respectively. Mating system differences were significant but differences between crosses within mating system were not. Estimates of heterosis of two-breed, backcross and three-breed cross pigs over purebreds were respectively, 1·1, 3·4 and 22·1% for rhinitis incidence and 10·1, 13·2 and 28·5% for rhinitis score.