Fat Deposition in Ruminants

Fat deposition inescapably accompanies skeletal growth and muscle accretion. In early growth deposition of fat and protein occur simultaneously, but beyond a certain body weight protein accretion becomes negligible, and fat gain becomes a large and constant fraction of weight gain. This pattern of tissue development forms the basis of the most successful current strategy for minimising carcass fat, namely the use of large, latematuring animals. At slaughter weight, these animals are much leaner than smaller, early-maturing animals. Other strategies that may be used to reduce fat deposition include the administration of natural and synthetic growth promotants, and padrenergic agonists, but two of the most effective agents, growth hormone and P-agonists, have not been approved for use in livestock production. Immunological approaches, which include enhancement of the activity of endogenous growth hormone and the reduction of fat deposits by injection of antibodies to the animals’ own adipocytes, show great promise, and may provide the meat industry with efficient and consumer acceptable methods of producing leaner animals.