Manipulation of the bacterial population of the intestine has been shown to result in changes in the structure and function of mucosal tissues. The objective of the present experiment was to investigate the effect of inclusion of a non-therapeutic antibiotic, virginiamycin, in the diet of sheep on the activity of the Na* -dependant transport of glucose and alanine by enterocyte cells. These transport mechanisms can be studied by isolation of brush border membrane vesicles following sub-cellular fractionation of the mucosal tissues.

Tissue was obtained from two separate growth trials in which the effect of inclusion of virginiamycin on lamb growth was being studied. In Trial 1 (glucose studies) the animals had been fed a concentrate diet plus hay ad libitum and virginiamycin was included at 100 ppm in the treatment group. In Trial 2 (alanine studies) the sheep were fed a concentrate diet with virginiamycin included at 50 ppm in the treatment group.

The potential of antibodies raised against insulin-like growth factor-1 (IGF-1) as a treatment to enhance the anabolic actions of IGF-1 has been demonstrated in both rodent and ruminant models. We investigated whether treatment of genetically normal rats with anti-IGF-1 immunoglobulin (Ig, raised in cattle) would enhance growth and if anti-IGF-1 Ig treatment would ameliorate live-weight loss in genetically normal rats offered a severely protein-restricted diet. Scatchard analysis was used to characterise ammonium sulphate precipitated bovine anti-IGF-1 Ig. Anti-IGF-1 Ig binding to 125I-IGF-1 yielded an almost linear Scatchard plot, with a Hill co-efficient of 0.951 ± 0.012, indicating a single class of IGF-1 binding sites. The affinity of anti-IGF-1 Ig for IGF-1 was 2.14 ± 0.66 × 109 l/mol. The non-immune Ig preparation did not bind IGF-1. Rats were offered either a diet with a normal protein level (20%) or protein restricted (4% protein), and each dietary group was further treated with twice-daily i.p. injections of either diluent phosphate buffered saline, non-immune Ig or anti-IGF-1 Ig. Dietary protein level had a significant effect on live-weight gain, but there was no effect of non-immune Ig or anti-IGF-1 Ig on live-weight gain. Treatment with anti-IGF-1 Ig prevented the significant depression of cumulative dietary intake observed in diluent, and non-immune Ig treated groups offered the 4% protein diet. The cumulative dietary intake of the anti-IGF-1 Ig treated, 4% dietary protein group did not differ significantly from those of the groups offered the 20% protein diet. In addition, within the 4% dietary protein group, rats treated with non-immune Ig exhibited a cumulative feed intake that was intermediate between that of the diluent treated and anti-IGF-1 Ig treated groups (P < 0.05). Size exclusion chromatography was used to characterise in vitro125I-IGF-1 binding in end-point plasma from each treatment group. In comparison to control groups, anti-IGF-1 Ig treatment resulted in substantially increased 125I-IGF-1 binding in the 30 to 40 kDa region and a concomitant reduction in elution of free 125I-IGF-1. Protein restriction markedly depressed IGF-1 binding at ∼150 kDa in the plasma of diluent and non-immune Ig treated groups. Anti-IGF-1 Ig treatment was effective in preventing this decrease in ∼150 kDa binding. Thus, anti-IGF-1 Ig appears to have a beneficial effect on dietary intake in protein-restricted rats, which is associated with induced changes in IGF-1 binding profiles in plasma.

In farmed salmonids the majority of consumed nitrogen is lost in metabolic waste products (mainly ammonia) and the faeces (Table 1). Any improvement in nitrogen retention, brought about by reductions in these components, would decrease environmental load. Inter-individual variation in retained nitrogen has been little investigated as a basis for selection of more efficient fish; this communication points to an experimental approach to measuring individual variation by concentrating on digestive efficiency and protein turnover as possible contributors to nitrogen retention. The utilization of dietary nitrogen was investigated in two species of farmed salmonid, the rainbow trout, Oncorhynchus mykiss and the Atlantic salmon, Salmo salar.

Recent studies have shown increased silage intake and improved milk fat concentration in dairy cows offered restricted compared to extensively fermented silages (Chamberlain et al., 1990; Mayne 1992). Changes in milk composition may be related to increased intake per se and/or alterations in rumen fermentation parameters. A study was therefore undertaken to examine the effects of silage fermentation type, dry matter intake and the addition of water soluble carbohydrate (WSC) or lactic acid on rumen fermentation parameters in dairy cows.

Two direct cut grass silages were prepared using either an inoculant (Ecosyl, 3 1/t, ICI. pic) or Maxgrass (BP Chemicals, 6 1/t). Five silage only treatments were offered to four ruminally fistulated dairy cows in a five period, partially balanced, changeover design experiment. Each period was of 4 weeks duration. Treatment 1: Inoculant treated silage (I), 2: Maxgrass silage (M), 3: Maxgrass ad-libitum (MAL), 4: Inoculant + sucrose (500 g/day) (IS), 5: Maxgrass + lactic acid (200 ml/day) (ML).

Field data were analysed in an attempt to identify factors contributing to differences between haemoglobin types n i the proportion of ewes lambing per ewe exposed to the ram in flocks grazing oestrogenic pastures. The number of ewes mated and the proportion of ewes failing to conceive to first service per ewe exposed to the ram were analysed. Neither was found to significantly differ between matings of different haemoglobin type. It is concluded that differences in reproductive performance between haemoglobin types could possibly result from differences in embryo survival.

One hundred and thirty crossbred gilts (Yorkshire × Duroc × Hampshire) were exposed to either natural (40 lux) or supplemental lighting (700 lux) beginning at 8 weeks of age. Gilts received supplemental lighting from 40-W flourescent bulbs from 05·15 to 09·00 h and 16·30 to 20·15 h from 9 September to 22 April. At 4 months of age, all gilts were exposed daily for 15 min to mature boars five times weekly. Twelve gilts from each group were slaughtered at 4, 5, 6 and 7 months of age. All gilts were bled from indwelling cannulas at 20-min intervals for 4 h the day preceding slaughter. In addition, blood samples were drawn weekly from 17 gilts in each group from 7 to 9 months of age and analysed for progesterone to determine age of puberty. Twelve of 17 gilts that received supplemental lighting reached puberty at 228 (s.e. 11) days of age whereas 11 of 16 gilts that received natural lighting reached puberty at 252 (s.e. 7) days of age (P = 0·07). No significant differences occurred in anterior pituitary gland weight or pituitary concentration of LH, mean concentrations of serum LH or number of LH secretory spikes between natural and supplemental-lighted gilts at each month (all P > 005). Concentration of oestradiol-17β and progesterone in follicular fluid was similar between treatment groups within months and follicular size (P > 0·05). Content of GnRH in the stalk-median eminence, preoptic area and hypothalamus proper were also similar between treatment groups (P > 0·05). In summary, supplemental lighting reduced the age of puberty in gilts without a detectable change in pituitary, hypothalamic or ovarian parameters.

Three different stages of pig antral follicles have been studied in a granulosa-cell transcriptome analysis on nylon microarrays (1152 clones). The data have been generated from seven RNA follicle pools and several technical replicates were made. The objective of this paper was to state the feasibility of a transcriptomic protocol for the study of folliculogenesis in the pig. A statistical analysis was chosen, relying on the linear mixed model (LMM) paradigm. Low variability within technical replicates was hence checked with a LMM. Relevant genes that might be involved in the studied process were then selected. For the most significant genes, statistical methods such as principal component analysis and unsupervised hierarchical clustering were applied to assess their relevance, and a random forest analysis proved their predictive value. The selection of genes was consistent with previous studies and also allowed the identification of new genes whose role in pig folliculogenesis will be further investigated.

Eighteen male and 18 female weaned rabbits were randomly allocated to two diets formulated to give energy concentrations of 8 (LE) and 10 (HE) MJ metabolizable energy per kg dry matter and three target slaughter weights (1·5, 2·25 and 3·0 kg live weight) to give a 2 × 2 × 3 factorial design with three replicates. Voluntary food intake and live-weight gain were monitored and the carcasses chemically analysed. The metabolizable energy concentrations of the diets were determined by balance and found to be 9·87 and 6·84 MJ/kg dry matter for diets HE and LE respectively.

Rabbits fed the LE diet consumed more dry matter (P < 0·001) and metabolizable energy (P < 0·01) in total, but grew more slowly than those fed the HE diet (P < 0·001). A diet × slaughter weight interaction occurred (P < 0·01); rabbits of the LE–3 kg treatment took longer to reach target weight as a result of a flattening of their growth curve.

Rabbits fed the LE diet had lower killing-out proportions (P < 0·05), heavier gut weights (P < 0·05) and gut contents (P < 0·05), but lighter livers than those fed the HE diet. Killing-out proportion progressively increased with increasing slaughter weight. External offal weight as a proportion of live weight tended to increase while internal offal weight as a proportion of live weight tended to decrease as slaughter weight increased. The carcasses of rabbits slaughtered at 3 kg had lower moisture contents (P < 0·001), greater fat contents (P < 0·001) and lower ash contents (P < 0·05) than other slaughter treatments. A significant diet × slaughter weight interaction occurred in fat content, with rabbits of the LE–3 kg treatment having proportionally more fat. With age at slaughter as a covariate, rabbits fed the HE diet had proportionally more fat (P < 0·05).

It is hypothesized that the fat colour of steers raised at pasture can be manipulated by altering animal growth patterns using the effects of post-pubertal surgical castration and oestradiol treatment. The fat colour of 151 steers of three genotypes of beef cattle, castrated at approximately 9 months or 18 months of age and treated, or not treated, with oestradiol after castration, was studied.

Surgical castration of beef cattle at both 9 months of age or 18 months of age caused no readily apparent animal welfare problems. The combined effects of early or late castration and oestradiol treatment produced varying growth patterns with early castrates exposed to two post-castration episodes of growth associated with carotene-rich forage and late castrates only one such episode of growth.

Late castrates and early castrates treated with oestradiol had a less yellow fat than early castrates not treated with oestradiol. The proportion of carcasses with commercially significant yellowness in the fat was decreased by either late castration or by oestradiol treatment. There was no effect of genotype on fat colour.

Leg disorders in male turkey breeding stock are associated with pain during locomotion (Duncan et al 1990). Musculo-skeletal diseases are prevalent in broiler breeder males and the experiment was designed to evaluate birds of two ages for evidence of pain during movement. Two experiments were conducted, the first examined differences in sexual motivation and the second the rate of walking towards a food reward. At the end of the experiment the birds were killed and the legs dissected to establish the presence of musculoskeletal disease.

Commercial broiler breeder males were housed singly with 15 females in 4 rooms each containing 12 floor pens measuring 1.5 x 2.4 m. There were 24 males in each of two age groups (40 and 60 weeks at the start of the experiments). To determine sexual motivation, males were removed to an empty pen in a spare room. They were returned after 3-5 h and observed for 15 min. The time to make a sexual approach (AP) and to mount a female (MT), and the number of copulations were recorded on three different days. Subsequently, males were trained to walk through a 20 m long alley constructed of hardboard to receive their daily food allocation. During testing, the time taken to reach the food was recorded 3 times before the male was returned to its pen. The males in two rooms were used in a 2-period crossover experiment to evaluate the effects of naloxone (an opiate receptor antagonist) and three analgesics on walking speed (Table 1). All measurements of time were transformed to natural logarithms for analysis. A censored analysis was used for AP and MT. The total number of copulations observed (COP) was modelled using Poisson errors. The models included effects for age and day (where appropriate). The data were reanalysed with the lesion score as a fixed effect. The initial model for walking speed included period and carry over effects. Mixed model methods (REML) were used to assess the final model with birds as blocks and treatment and lesion as main effects.

Data for a total of 3715 cattle from four sources were used to examine the relative importance of live weight at slaughter, and visual assessments of carcass conformation and subcutaneous fat cover, as predictors of killing out. The sources were the Meat and Livestock Commission's beef breed evaluation programme (1689 steers of different breeds and crosses), the beef demonstration unit at the National Agricultural Centre, Stoneleigh (814 commercial dairy-bred cattle), an East Anglian abattoir (405 commercial cattle) and the Milk Marketing Board's Warren Farm (807 dairy-bred steers by different sire breeds). An assessment of live body conformation was also examined as a predictor in the Warren Farm data.

Carcass conformation provided a more precise prediction of killing out than did either live weight or subcutaneous fat score. Regression coefficients in the different groups ranged from 5·4 to 12·0 g/kg for each increase in conformation class (six-point scale). The live conformation assessment was a less precise predictor (within sire breed residual s.d. = 17·7 g/kg) than the carcass assessment (15·6 g/kg).

Use of a farrowing crate can benefit newborn piglets but imposes severe restriction on sow movement throughout lactation. It is necessary to find a compromise between the commercial requirements for control in the immediate neonatal period, to maximise piglet survival, and enhanced welfare for the animals, by reducing environmental restriction. This might be achieved by combining individual farrowing in controlled systems with later multisuckling of a group of contemporary litters in a larger and more diverse environment. Application of modern understanding on nutrition and environment could allow such systems to function more successfully than in the past and provide a commercially attractive option.

A total of 33 purebred Landrace or Large White sows and their litters were used in the study. All sows farrowed in commercial accommodation based on farrowing crates in partly slatted pens. These pens had a covered creep area for the piglets which was bedded with shavings. Control litters remained in this accommodation until weaning. Experimental litters were moved to specially constructed multisuckling pens.

Six ewes were given a white clover/grass silage with a high content of cyanogenetic glycosides during the last 69 to 97 days of pregnancy (group CN+), while the five ewes of the control group (group CN−) received a white clover/grass silage with a low content of cyanogenetic glycosides during the last 67 to 92 days of pregnancy. Uniodized salt was the only mineral supplement offered. The daily intake of cyanide (in the form of cyanogenetic glycosides) and of selenium per animal was 1000 and 60 mg of cyanide and 30 and 23 μg of selenium in group CN+ and CN− respectively. Initial erythrocyte glutathione peroxidase activity (GPx) was identical in both groups. Two weeks before parturition GPx activity was significantly lower in the ewes of group CN+ than in the ewes of group CN−. The newborn lambs of the group CN+ had significantly lower erythrocyte GPx activities (P < 0·01) and tended to have higher plasma creatine kinase activities (P = 0·07) than the lambs of the group CN−. The results show that the intake of cyanogenetic glycosides affects the selenium status of sheep and increases the susceptibility of lambs to nutritional myopathy if the selenium content of the ration is marginal.

Plasma thyroxine concentrations in the ewes in group CN+ were not reduced but their lambs tended to have slightly lower levels immediately after birth than the lambs of group CN− (P = 0·25). The intake of cyanogenetic glycosides presumably had no or at most only a slight effect on thyroid function, presumably because the body iodine reserves of the ewes were sufficient to offset the goitrogenic effect of thiocyanate.

Photostimulation is an effective means of manipulating reproductive activity in most British breeds of sheep. Short term light treatment can initiate oestrus cycles during June/July and thus provides the opportunity for autumn lambing (Williams, 1977). The most effective light treatments comprise a period of supplementary light followed by a period of long nights which requires controlled environmental housing. Recent investigations have demonstrated that melatonin treatment may replace the long night phase thus simplifying management (Williams, 1985). Attempts to dispense with the period of supplementary light by transferring Spring lambing Welsh Mountain ewes abruptly to long nights during early Spring were not as successful as the conventional type of light treatment (Williams, 1967). This investigation was undertaken to compare the response of adult Suffolk crossbred ewes given melatonin in the Spring with or without a priming period of supplementary light.

The effect of time after feeding on the distribution of nitrogen (N) in digesta from various segments of the gastrointestinal tract was studied in sheep given a diet of chopped hay once daily. Four groups of four animals were slaughtered at 2, 8,16 and 24 h after feeding and digesta were separated into large (>1180μm), medium (300 to 1180 μm) small (45 to 300 μm) and fine particles and liquid (<45 μm) fractions. The N pool in the reticulorumen decreased with time after feeding but post-ruminal N pools changed very little. Changes in N distribution within the reticulorumen reflected reductions in large particles and increases in fine particles and liquid fractions, the intermediate fractions remaining fairly constant.

The linear growth rate of wool on three sites on each of six Wenslcydale × Blackface lambs was measured by wool fibre autoradiography following 11 injections of 35S-cystine. The first injection was given at 09.00 h, so that alternate 36h intervals between injections represented predominantly day (09.00 to 21.00h) or night (21.00 to 09.00 h). The overall mean growth rates on shoulder, mid-side and breech were 0·83, 0·96 and 0·95 mm/day. Differences between day and night growth rates were very small (proportionally<0·05) and inconsistent in 16 of the 18 samples; although breech samples from two sheep showed up to 0·14 faster growth in daytime, a circadian rhythm of wool growth seems unlikely on this evidence. Both linear wool growth rate and food intake increased steadily throughout the experiment.

Mid-side wool growth rates in a second group of three crossbred longwool lambs averaged 0·79, 100 and 1·14 mm/day and were relatively stable over a period of several months.

Given the very recent investment in research on organic rabbit production, many knowledge gaps remain. Simulation models based on data from experiments and farms may help generate general principles for organic rabbit production. Our goals were to (i) develop a model to simulate intake regulation and growth of rabbits raised on pastures, (ii) validate this model under a diversity of conditions and (iii) conduct a simulation experiment to predict the potential to decrease the supply of complete feed by increasing the grazing area per rabbit. The model developed (PASTRAB) simulates organic rabbit fattening on pastures in four main submodels that represent dynamics of (i) herbage standing biomass, fill and feed values; (ii) intake of herbage, complementary feed (i.e. complete pellets, cereal–legume grain mixtures) and hay as regulated by herbage allowance, fill and feed values of feedstuffs and rabbit physiological parameters; (iii) conversion of rabbit intake into live weight gain; and (iv) rabbit mortality. The model also calculates gross margin per rabbit sold. Model accuracy was assessed by considering the fit between observed and predicted herbage intake, which was low, with a relative root mean square error (rRMSE) of 51% and 66% on grass-based and legume-based pastures, respectively. However, the standard deviations of observed herbage intake were similar to the root mean square error of predicted herbage intake, indicating that it would have been difficult to improve model calibration. The fit between observed and predicted rabbit live weight was acceptable, with an rRMSE of 11% and 10% for grass-based and legume-based pastures, respectively. Simulated scenarios showed that a decrease in complementary feed combined with an increase in the grazing area per rabbit had little impact on average daily growth and gross margin per rabbit but increased herbage use efficiency. With 90 g of complementary feed per day and grazing of 0.4 m²/rabbit per day, herbage use efficiency was 22%, with average daily growth of 21.6 g/day and gross margin of 18.80 €/rabbit. With no complementary feed and grazing of 1.2 m²/rabbit per day, average daily growth decreased (19.2 g/day), but herbage use efficiency reached 100% and gross margin reached 19.20 €/rabbit. We used PASTRAB in participatory workshops with farmers so that the latter could explore adaptations to their current practices. Overall, farmers considered the model predictions realistic, and some of them decided to adapt some of their management practices immediately after the workshops.

Intake of herbage by grazing animals is determined by the weight of herbage harvested per bite and the number of bites taken. A knowledge of ingestive behaviour can, therefore, play a valuable role in understanding animal responses to changes in sward conditions and management practices and thus aid the interpretation of results from grazing experiments. This paper will firstly consider briefly some methods of recording behaviour and, secondly, present some results illustrating the use of behaviour recording within a grazing experiment.

Direct observation is the most frequently used method of recording behaviour. It is, however, laborious and often carried out under unpleasant conditions; it is difficult to record activities continuously and in some cases it is not possible to directly observe a particular behaviour. These limitations have led to numerous attempts to record grazing behaviour automatically.

The purpose of this work was to investigate the relationship between individual animal performance and production per unit area of land of steers of different potential growth rate under different grazing stocking rates (SR). The analysis involved 160 steers divided equally between two breeds, over 2 years at four SRfor each breed and two replicates for each SR. Thus there werefive steers per replicate. The breeds were purebred Aberdeen Angus (Angus) and 4 Limousin (Limousin). After weaning steers were grazed for 251 days on a pasture dominated by Festuca arundinacea. Given that equal SR does not equate to equal treament for breeds characterized to be of different size and rate of growth at a given age, the analysis was undertaken on the basis of three categories of metabolic body size per ha (S). The variables analysed were individual live-weight gain (final minus initial weight, kg), relative individual live-weight gain (logefinal weight - loge initial weight) and production (kg/ha). A mixed model was used to examine effects of breed, S, year and the interactions between these variables. In general significant (P < 0·05) differences were found for all factors of classification and interactions. Independent linear regressions were calculated for each breed between absolute live-weight gain, relative live-weight gain, and production on S. It was concluded that there was a genotype × environment interaction, with the Angus breed tending to show a higher production per unit area than the Limousin, especially at high levels of S when scarcity of forage was apparent. Nevertheless Limousin steers had higher absolute individual performance than the Angus. The higher production of the smaller breed may be explained by a higher SR at a given S level and also by its higher relative individual live-weight gain in relation to that of the larger breed. The data were coded to use Mott's model to study the relationship between absolute performance (kg) and production (kg/ha). However this model ignores the existing interaction involving breeds.

In 1,347 parentage cases in cattle it was determined whether conception resulted from the first or second service. Among cows served twice within short intervals (1–11 days) about 20% remained pregnant from the previous service. At an interval of one day this proportion amounted to 37%.

About three-quarters of the cows had service intervals of 18–24 days. In most of these the calving took place between the expected dates according to the two services. In 6% of the cases with intervals of 18–24 days pregnancy resulted from the first service. It was estimated that about 1% of all cows mated twice within these intervals had become pregnant from the first service.

Rules are suggested for when blood grouping should be required for registration of pedigrees in the herd book.