This study was designed to assess the effects of amino acid supply and growth hormone (GH) treatment on IGF-I gene expression of ovine hepatocytes and to determine the possible mechanism(s) involved. Using a riboprobe that detect both type 1 and type 2 mRNA transcripts, GH and amino acid were shown to have separate and interactive effects on the regulation of IGF-I gene expression and these effects were similar for both transcripts. The stimulatory effects of GH and amino acid supply were shown to depend at least in part on transcriptional control, since transcription blockade resulted in the abolition of both the GH and amino acid dependent responses. The effect of amino acid supply could not be attributed to any single amino acid (so far studied). However, partial effects of methionine and the branched chain amino acid limitation on GH dependent IGF-I mRNA expression were observed. Also methionine limitation caused the abolition of GH dependent IGF-I peptide secretion. The observed effects of amino acid supply on IGF-I gene expression were not dependent on the mTOR, PI3 kinase or MAP kinase pathways. However, GH dependent IGF-I peptide secretion was apparently PI3 kinase and MAP kinase sensitive. In conclusion, IGF-I gene expression is highly sensitive to GH and amino acid supply. The mechanism by which amino acid supply regulates IGF-I gene expression is mTOR independent. GH appears to regulate IGF-I production at the gene expression level, and also possibly at a translational/post-translational level through a PI3 kinase and MAP kinase dependent mechanism which may be methionine sensitive.

No description available.

No description available.

Group housing of sows and piglets during the lactation period in a multisuckling system was studied to identify the factors affecting the behaviour and performance of sows and piglets. Comparison was made with sows and piglets in a conventional farrowing pen with crate system. Cross-suckling, additional piglets at the udder during nursing periods, grouping piglets and changing sow location, which might all have contributed to the observed differences in behaviour and performance of the sows and piglets, were each studied separately in more controlled farrowing house conditions. It was shown that welfare of the sow as improved in the multisuckling system as the sows had free movement, expressed more natural behaviour and had social interaction, relative to a sow in a crate. Fighting at grouping was low when using a docile breed (Manor Meishan). The production of the sow was comparable to sows in the conventional system. Welfare of the piglets during grouping was impaired, as they suffered from being placed in a cooler environment (below their Lower Critical Temperature) compared to a conventional farrowing pen with crate system. Piglet mortality rate by being crushed was slightly increased when sows had free movement. Disruption of nursing with adverse effect on the performance of the piglets was observed following grouping with an increased incidence of cross-suckling and a greater number of piglets at the udder during nursing. It can be concluded that grouping sows and piglets during the lactation period can enhance the sows welfare and still provide similar piglet production to the farrowing pen with crate system. However, problems occur for the piglets and good management is needed as the ill-thriving animals are more difficult to identify and treat in such a loose housing system.

Three experiments were carried out to determine i) the quantity and composition of maize forage harvested at different stages of growth, ii) the effect on the milk yield of dairy cows fed on maize forage silages harvested at two stages of maturity together with two levels of dairy concentrate, iii) the effect of supplementing early and late cut silages with either dairy concentrate or cottonseed cake on dry matter intake and milk yield of dairy cows. Forage dry matter yield showed a small non-significant increase with advancing maturity. The contents of dry matter, ash, acid detergent fibre and lignin increased significantly with crop maturity. Crude protein content and dry matter degradability declined significantly as the crop matured. Grain and stover production were significantly reduced by early defoliation. The effects of stage of maturity on the composition of forage and the yields of grain and stover were smaller in the last three stages of defoliation. The effect of type of silage on dry matter intake was inconsistent in the three feeding trials. Dairy cows consumed similar amounts of either early or late cut maize silage in the first year. In the second trial, cows that were fed on early silage ate significantly higher amounts of silage dry matter than those fed on late silage. In the third year the opposite trend was observed. Within each silage, level and type of concentrate offered to the animals had no influence on silage intake. There were no substitution effects in the two feeding trials when different amounts of concentrate were fed with the silages. Milk production from cows that were fed on early silage was about 10% higher than that of cows fed on late silage. This difference was significant in two years. The higher level of concentrate supplementation gave 9% more milk than the lower level. Feeding the silages with dairy concentrate rather than cottonseed cake gave more milk per cow per day. There were no interactions between silage and concentrate effects on milk yield. Milk production when cows were grazing followed similar trends to those recorded in the silage feeding periods. The cows that were supplemented with four kg of concentrate partitioned more energy towards body weight gain than those fed on two kg of concentrate. Efficiency of utilisation of energy for milk production was lower when cows received four rather than two kg of concentrate. Metabolisable energy in early silage was better utilised for milk production than that in late silage. Feeding the two silages with cottonseed cake improved efficiency of energy utilisation for milk production.

No description available.

This study reviews the factors affecting reproductive efficiency in PAC pigs and identifies the major constraints in traditional pig production systems in relation to climatic environment, nutrition and management practices in the hills of eastern Nepal. The different factors affecting reproductive efficiencies were investigated and the possible means to overcome these problems are outlined under Nepalese situations. The majority of the pigs in the hills of Nepal are reared below their LCT throughout the year, causing an estimated loss of 43 % of the total feed intake requirements by climatic penalty. If this feed loss could be effectively utilised by improving housing conditions, the productivity of pigs could be greatly improved. Improvement in housing conditions seem to be the cheapest alternative for improving efficiency in Nepalese situations. Improvements in nutrition of rearing gilts and lactating sows resulted in improvements of reproductive outputs in both station and village experiments. Modified suckling management in late lactation resulted in shorter weaning to remating interval and needs to be introduced in the villages for better reproductive efficiency of pigs. Farmers in the hills of Nepal do not rear boar and sows together due to limitation of feed availability. Under such circumstances, an artificial boar pheromone (Boar Mate) had a beneficial effect on stimulating and detecting oestrus in PAC pigs. However, Boar Mate is not easily available and hence it is recommended to carry out further critical evaluation of boar urine, which gave promising pilot results, as an alternative.

No description available.

No description available.

The effects of age and plane of nutrition on the body and carcass composition and mohair fibre yield and quality of British Angora wether goats slaughtered at six, 12, 18 and 24 months of age were investigated. Carcass yield, composition and conformation improved with increasing age and plane of nutrition. Greasy fleece weight also increased with increasing age and plane of nutrition but fibre quality declined since the increase in mass was achieved by means of increased fibre diameter with no effect of age or plane of nutrition on the fibre elongation rate. There was a constant relationship between the increase in fibre diameter with age and fleece mass which was not affected by plane of nutrition. Similarly there was no significant effect of plane of nutrition on the relationships between fibre diameter and the weight of various body and carcass components. A strong relationship between fibre diameter and the weight of fat in the body or carcass suggested that the increase in fibre diameter with age of the goat was influenced by cumulative feed intake rather than by fat-free body size. The allometric growth patterns of the body and carcass of the Angora goat conformed with the patterns established for other domestic species, with early maturity of the external offal and vital organs, later maturity of the carcass and body fat, and a centripetal pattern of development. There was no effect of plane of nutrition on the allometric growth patterns of the fat-free body or carcass, but decreasing the plane of nutrition resulted in a uniform retardation of all body parts and carcass tissues and a significant effect on the relative growth rate of body and carcass fat. Regression equations were formulated to predict the half carcass composition of Angora wether goats using sample joint dissection data. The most accurate predictions were achieved with data from the leg and the best end of neck combined in multiple regression equations. A second experiment to investigate the effects of long term undernutrition followed by realimentation on the growth rate and composition of empty body weight gain revealed no evidence of compensatory liveweight gain in the Angora goat.