There is evidence that the growth of female rats and sheep may be constrained by physiological concentrations of glucocorticoid hormones. This study was designed to examine the effects of trilostane, an inhibitor of adrenal steroidogenesis, on serum cortisol concentrations and growth in pigs.

First, trilostane was tested at three doses (250 mg, 500 mg and 1000 mg per pig) to examine its effect on serum cortisol concentrations. A reduction in serum cortisol concentration was observed 2 to 4 h after oral administration of trilostane (P < 0·05) and the adrenal response to a challenge dose of ACTH was reduced 4 to 6 h after administration (P < 0·05), at all doses tested. In a second experiment, trilostane (9·24 mg/kg body weight) was administered orally to 10 pigs twice daily for 35 days to examine its effects on growth rate. A further 10 pigs received a placebo. Trilostane did not affect weight gain or carcass composition, but caused a reduction in food intake (P < 0·05). Adrenal weight was increased by trilostane treatment and liver weight was reduced.

These results show that trilostane is effective at lowering serum cortisol concentrations acutely, but suggest that physiological concentrations of glucocorticoid hormones may not retard growth rate in barrows.

The objective of this study was to investigate the effect of various factors on average pig weight at weaning on farms using early weaning. Farms were selected based on average weaning age and whether they recorded lactation food intake and litter weights at weaning. The database contained 9834 litter weights and 8903 food intake records. Average pig weight at weaning, litter size at weaning, weaning age, and average daily food intake during lactation (ADFl) were 4·9 (s.d. 1·0) kg, 9·3 (s.d. 1·6) pigs, 16·8 (s.d. 2·8) days, and 4·9 (s.d. 1·1) kg, respectively. Litter size, weaning age, parity, farrowing season, and ADFl groups influenced average pig weight at weaning (P < 0·01). Three two-way interactions between parity and season, weaning age and farrowing season, and weaning age and ADFl groups were found fP < 0·01). Average pig weights for litter sizes between six and 10 were higher than those between litter sizes one and four, and 11 and 22. Parity 1 sows produced lighter pig weights than any other parity group during any other season (P < 0·01). Average weights of weaned pigs farrowed during the summer in all parities groups were lighter (P < 0·01) than those during the autumn. Pig weights for weaning ages between 22 and 21 days during the summer tended to be lighter than those during the autumn. Pigs weaned between days 16 and 22 of age in the high ADFI group (>5·6 kg) were heavier (P < 0·01) than those in the low ADFl (> 4·2 kg) group.

The origins and phylogeny of different sheep breeds has been widely studied using polymorphisms within the mitochondrial hypervariable region. However, little is known about the mitochondrial DNA (mtDNA) content and phylogeny based on mtDNA protein-coding genes. In this study, we assessed the phylogeny and copy number of the mtDNA in eight indigenous (population size, n=184) and three introduced (n=66) sheep breeds in China based on five mitochondrial coding genes (COX1, COX2, ATP8, ATP6 and COX3). The mean haplotype and nucleotide diversities were 0.944 and 0.00322, respectively. We identified a correlation between the lineages distribution and the genetic distance, whereby Valley-type Tibetan sheep had a closer genetic relationship with introduced breeds (Dorper, Poll Dorset and Suffolk) than with other indigenous breeds. Similarly, the Median-joining profile of haplotypes revealed the distribution of clusters according to genetic differences. Moreover, copy number analysis based on the five mitochondrial coding genes was affected by the genetic distance combining with genetic phylogeny; we also identified obvious non-synonymous mutations in ATP6 between the different levels of copy number expressions. These results imply that differences in mitogenomic compositions resulting from geographical separation lead to differences in mitochondrial function.

Hovell et al. (1986) proposed that degradation characteristics of forages, as measured in nylon bags, may have useful application in predicting voluntary intakes. They reported intakes of four hays by sheep were more closely related to the potential degradability of forage dry matter (DM) than to in vivo The present work was undertaken to examine these relationships with forages and with both young growing cattle and sheep.

Seven forages were prepared with the objective of providing material wide range of voluntary intake. The forages were:

• (i)WS, wheat straw

• (ii)AWS, round-baled WS wrapped in 4 layers of overlapping plastic sheet (Silawrap; Volac Ltd), injected with 32% aqueous ammonia at the rate of 40kg/1000kg DM

• (iii)H1, first cut ryegrass hay

• (iv)H2, second cut ryegrass hay from the same field as (iii)

• (v)S2, 50% DM silage, baled and wrapped with Silawrap, prepared from the same crop as H2

• (vi)ES2, the same crop as S2 sprayed with a mixed enzyme preparation (Deezyme, Finnish Sugar Company Ltd.) at 0.81/tonne immediately before baling and wrapping with Silawrap

• (vii)AS2, S2 treated with aqueous ammonia in the wrapped bale as for AWS. All forages were fed in the long form except WS which was coarsely chopped through a straw chopper without any retaining screen into approximately 7cm lengths.

Eight wether lambs were used to determine effects of an oestradiol-17β (E2β) implant on metabolic responses to an epinephrine challenge. Blood was sampled before and after an epinephrine challenge, on days 0 and 22 of E2p implantation.Oestradiol-17 ft implants increased pre-injection (basal) serum insulin (INS), growth hormone and free fatty acids (FFA), and decreased basal serum urea nitrogen. After 21 days of E2Pimplantation, total concentrations of FFA decreased and INS increased in response to the epinephrine challenge compared with pre-implantation values. It is concluded that E2/3 implants alter metabolic responses to an epinephrine challenge in wether lambs.

In 1968-69 for a mean period of 101 days before lambing, 72 cross-bred ewes, and in 1969-70 for a mean period of 88 days, 107 ewes were given roughage daily in the form of (a) 0·91 kg field-cured hay (b) 0·45 kg of hay plus 0·23 kg dried sugar-beet pulp nuts, or (c) 0·45 kg of pulp nuts. Each diet was supplemented by a concentrate allowance. From the 6th week before lambing was due to start, this allowance was progressively and uniformly increased.

There was no evidence that the dried sugar-beet pulp had adversely affected performance in terms of ewe body-weight change, lamb numbers, litter weight at birth or 4 weeks of age, fleece weight or general health. It is therefore concluded that dried sugar-beet pulp can be used safely as a replacement for hay in supplying up to 67% of the energy needed for maintenance by ewes.

An investigation was made of the association of transferrin types with birth weight, weaning weight and average daily gain from birth to weaning in three breeds of Iranian sheep. Transferrin type was not a significant source of variation in weight.

A by-product of the distilling industry designated ‘distillers’ grains plus solubles' was evaluated using forty-eight growing pigs. The product was included at 0, 14·7 and 25% in three diets in which the proportion of other constituents was adjusted to give similar concentrations of TDN, dry matter and crude protein.

The performance and carcass quality of pigs receiving 0% and 14·7% of the by-product in the diet was similar, but inclusion at 25% significantly reduced growth rate (g/day) from 632 for the 0% diet to 578.

In a recent study of the efficacy of two methods of oestrous synchronisation in dairy heifers, progesterone profiles and ultrasound results showed that late embryonic/early foetal loss had a small but nevertheless important effect upon pregnancy rates (Logue & others 1991). Since some preliminary results were available which showed that the use of a 3 mg norgestomet ear implant alone, rather than in combination with a 3 mg norgestomet and 5 mg oestradiol valerate injection (Crestar Intervet UK Ltd), enhanced pregnancy rates in beef heifers (Favero & others 1989) and the technique was being used in Embryo transfer (ET) recipients (Broadbent pers com) it was felt that a further investigation of the technique was merited.

Groups of Dorper lambs were castrated at three ages: shortly after birth, and at two and four months of age. All were slaughtered at an age of six months and the carcasses subsequently weighed, graded, measured and scored. The results indicate no marked differences in either weight or quality of carcass between the treatments. It is concluded that the operation can safely be carried out, depending upon circumstances, at any stage between birth and four months.

The objective of the paper is to assess the overall structural and competitive implications for the UK pig industry of the EC Single Market; colloquially known as “1992”.

Particular attention is paid both to the effect of those changes in the commercial environment which 1992 will introduce and, secondly, to those aspects which differentiate the UK pig industry from its continental competitors. Analysis of these aspects will assist in drawing conclusions as to the likely effect of the Single Market and in determining an appropriate strategy for addressing the new situation.

A body of admittedly largely circumstantial evidence suggests that the UK pig producer believes the advent of the Single Market will have little relevance to the way in which he conducts his business. This view is buttressed by his perception of the agricultural world as governed by the workings of the Common Agricultural Policy which is regarded as the principle influence upon agriculture and its commercial fortunes.

Two experiments were conducted to investigate the requirement for dietary crude protein (CP) in growing blue-breasted quail (BBQ). In Experiment 1, 300 1-day-old quails were randomly assigned to 10 groups according to a 2 × 5 factorial arrangement of treatments with two metabolisable energy (ME) levels (12.13 and 13.39 MJ/kg) and five CP concentrations (160, 190, 220, 250 and 280 g/kg) for 8 weeks. In Experiment 2, 300 1-day-old quails were subjected to a different factorial arrangement of treatments with two ME levels (11.51 and 12.13 MJ/kg) and five CP concentrations (210, 220, 230, 240 and 250 g/kg) for 28 days. Experiment 1 revealed that an interaction existed in weight gain between ME and CP levels in weeks 1 to 4. In both ME groups, quails receiving CP of 160 g/kg showed the least weight gains (P < 0.05). No differences (P > 0.05) existed in weight gain between the ME groups in which quails ingested CP of 250 and 280 g/kg, whereas quails consuming CP of 220 g/kg with an ME of 13.39 MJ/kg had smaller weight gain than did those ingesting higher CP concentrations (P < 0.05). Of main effects for weeks 1–4, quails treated with an ME of 12.13 MJ/kg consumed more feed than did those receiving another ME level, whereas quails in both ME treatments showed similar feed efficiencies. For weeks 5 to 8, no difference (P > 0.05) in weight gain, feed intake and feed efficiency was seen regardless of ME levels, and no interaction existed between ME and CP levels. In Experiment 2, the best weight gain and feed efficiency were achieved when the dietary CP concentration was more than 210 g/kg, and quails treated with 11.51 MJ/kg showed better weight gain and feed efficiency (P < 0.05) than did those that received 12.13 MJ/kg. Furthermore, the weight gains and protein intakes on the basis of per MJ from the two experiments were pooled together to estimate the protein intake necessary for the best growth performance by two mathematic models; they were then converted to dietary CP concentrations of 204 (minimum) and 233 g/kg (maximum) when ME was 11.51 MJ/kg. In conclusion, BBQ will achieve good growth performance with dietary CP of more than 204 g/kg on the basis of an ME of 11.51 MJ/kg in weeks 1 to 4.

Two pairs of uniformly treated identical twins were weighed four times daily for 16 days. In addition, daily growth rate was analysed for 10 pairs of identical twins kept on high and low planes of nutrition over a 16-week period.

Identical twins fluctuated in body weight from hour to hour and day to day in a significantly more similar manner than did unrelated animals. The greater similarity found when all animals were uniformly treated still persisted when identical twins were placed on different planes of nutrition.

Legislation to control veterinary medicinal products is undergoing continual development in the EEC and UK and therefore the risks are continually reassessed. In the present paper current and future legislation together with consumer concerns both real and imaginary are reviewed.

Since the EEC ban on hormonal growth promoter implants in 1986 the remaining legal products are all feed additives. Registration of feed additives in the EEC is controlled under Directive 70/524 and its various amending directives. this directive is concerned with all products added to feed and mainly includes substances used to affect the quality of the feedstuff i.e., emulsifiers, stabilisers, antioxidants, colorants and binding agents and also vitamins and micronutrients. The majority of growth promoters exert their affects by antimicrobial activity and these and certain prophylactic medicinal products such as coccidiostats are also included. All products with a therapeutic action are controlled under the Veterinary Medicine Directives 81/851 and 81/852, quite separate legislation and under the responsibility of a different department within the EEC Coimdssion. However, there is provision under Directive 84/587 amending 70/524 to transfer the medicinal feed additives to 81/851 and 81/852.

Binational genetic evaluation between Germany and France were performed for each type trait using a single-trait MACE (multiple across-country evaluation) model. Daughter yield deviations (DYD) of bulls having 30 equivalent daughter contributions or more were the data for parameter estimation. Full pedigree information of bulls was used via sire and dam relationships. In general, across-country genetic correlation estimates were in agreement with what is observed by Interbull. The estimated correlations were over 0.93 for stature, rump angle, udder depth, front teat placement, teat length and rear teat placement. These traits have been classified in both countries for a long period of time. However, some other type traits were included later in the French type classification system (most of them since 2000): chest width, body depth, angularity, rump width, rear leg rear view, fore udder and rear udder height. The estimated correlations for these traits were relatively low. In order to check changes in genetic correlations over time, data from bulls born until the end of 1995 were discarded. Higher genetic correlation estimates between both countries were obtained by using more recent data especially for traits having lower genetic correlation, e.g. body depth correlation increased from 0.55 to 0.83. Once genetic correlations were estimated, binational genetic evaluation between Germany and France were performed for each type trait using DYD of bulls. The rankings of bulls obtained from this evaluation had some differences with Interbull rankings but a similar proportion of bulls from each country was found. Finally, more computationally demanding binational evaluations were performed using yield deviations of cows for binational cow comparison. The rankings obtained were influenced by the number of daughters per bull and heritabilities used in each country.

1. The primary growth of perennial ryegrass was cut between 7 and 9 June and ensiled with formic acid at 2·5 1/t. The regrowth was cut on 24 July; part was dried at high temperature (dried grass), the remainder was left to dry in the field (hay). The dried grass (DG) and part of the hay were ground and pelleted, the hay being pelleted alone (PH) or with the addition of formaldehyde at 20 g/kg crude protein (PHF). The remainder of the hay was offered in the chopped form (CH). The four supplements (CH, PH, PHF, DG) were offered at two levels, 6·5 (L) and 130 (H) g dry matter per kg live weight to 54 British Friesian steers (initial live weight, 110 kg) receiving the silage ad libitum.

2. The silage had a high pH and a high proportion of the total nitrogen was in the form of ammonia, indicating poor fermentation. The solubility of nitrogen in the supplements was highest (262 g/kg total nitrogen) in CH, progressively less in PH and PHF and lowest (122 g/kg total nitrogen) in DG.

3. Total dry-matter intake was highest with DG at the higher level of inclusion. Dry-matter intake was significantly higher for PH and PHF than for CH (P < 0·001). However, intake of digestible energy did not differ between hays. Live-weight gain was increased from a low level of 0·24 kg/day (silage alone) by all supplements, but this effect was greater with DG than with the hays (P < 0·001). Level of supplementation increased live-weight gain from 0·54 to 0·74 kg/day.

4. Supplements of dried grass gave higher live-weight gains than did hay made from the same sward. However, the results indicate that supplementation of badly preserved silage with grass hay of good quality can produce acceptable levels of performance of up to 0·70 kg/day in 4-month-old steers. Processing of the hay had little effect on animal performance.

At birth, the Barki lambs used in this experiment were randomly allocated to three groups which numbered 133, 126 and 154 lambs of both sexes weaned at the ages of 10 weeks (Group I), 12 weeks (Group II) and 16 weeks (Group III) respectively.

The most pronounced differences between the three groups of lambs in their body weights took place at the age from 4 to 6 months. Group II lambs performed as well as or even slightly better than the other two groups, which leads to the conclusion that as far as the body weight of lambs is concerned there is no need to extend their suckling period more than 12 weeks.

The three groups of lambs varied little in their mortality rates from 2·5 to 12 months of age.

An experiment was carried out at Terrington to investigate the effect of pre-weaning solid feed or no pre-weaning feed for suckling piglets using diets of either high or low protein levels. Previous work at Terrington with 3 week weaned pigs showed that post-weaning performance had a big effect on subsequent performance so the trial pigs were monitored through to slaughter. Research at Bristol University showed that “abrupt weaning”, i.e. no pre-weaning feed can reduce post-weaning diarrhoea.