Monoclonal antibody OA11 was raised against ovine GH; its effects on GH activity were examined in a target species relevant for animal production in vivo. The monoclonal antibody was found to enhance the galactopoietic response to exogenous GH in adult lactating ewes and also to potentiate the diabetogenic activity of both exogenous and endogenous GH in ewe lambs. Thus it was shown that GH activity may be manipulated above its usual dose-response range in normal, intact animals of commercial importance via immunological means.
Recombinant-DNA-derived bovine somatotropin has similar metabolic activities to pituitary-derived hormone in both laboratory animals (growth promotion), and in dairy cows (milk stimulation), but anabolic effects have not been investigated in ruminants. Although there is some controversy as to whether recombinant somatotropin has intrinsic lipolytic activity, the release of non-esterified fatty acidsin vivofollowing a single injection (Hartet al. 1984) and the reduction in carcass fat after long-term treatment periods in sheep (Johnssonet al. 1986) indicate lipolytic and/or antilipogenic activity. This study was initially planned to examine these activities during long-term administration of recombinant bovine somatotropin in lambs. However, four cases of uriolitholiasis caused the proposed study of fat turnover to be abandoned and the following data are from those lambs which showed no symptoms of this problem.
Neonatal mortality represents a major loss of production efficiency for herds throughout the world and despite research and development work spanning many years the losses are still not tolerable either in economic terms or in terms of animal welfare. In the United Kingdom where producers are amongst the very best, the Meat and Livestock Commission estimate that pre-weaning mortality nationally is of the order of 12.8% of all piglets born alive (MLC, 1984).The causes of death are well documented (Spicer et al 1986) but overlying, starvation, chilling and pathological problems are principal components. Central to all of these factors may be the events occurring within the first hours of a piglets life and those animals which are first born which suckle quickly and effectively have a high probability of survival.Conversely, those piglets which are later born and which are also smaller than the average for the litter may be at a severe disadvantage because of the competitive environment around the udder of the sow after parturition. Modern hybrid sows also vary widely in their ability to produce colostrum (Varley,1984)
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