Development of an optimum production system for Australian grain-fed quality beef for the Japanese market

Summary

The Japanese market for Australian beef has expanded rapidly and is likely to increase even further with liberalisation in 1991. This is creating pressure for the Australian industry to supply the highly marbled, high quality product this market demands. At present Australia is supplying about 56 percent of the bottom 21 percent of the Japanese market, 16 percent of the middle 66 percent of the Japanese market and only 2 percent of the top end of the market, which is largely the province of the Japanese farmers. The potential for improvement and expansion amounts to > $100 million for the Australian Beef Industry. Hence, the rapid expansion of feedlots and recent establishment of Japanese consortia in the Australian industry.

Marbling is primarily a genetic trait of cattle which is capable of nutritional/metabolic manipulation. It has been shown that the various fat depots of cattle utilise different proportions of substrates to synthesise lipid through lipogenesis, ego subcutaneous fat utilises mainly acetate and little glucose but intramuscular fat utilises largely glucose and little acetate. Furthermore, intramuscular fat accumulates long chain fatty acids for lipid synthesis to a much greater extent than does subcutaneous fat. For these reasons manipulation of the diet may have some potential to increase marbling (intramuscular fat) without creating excess subcutaneous or seam fat deposition. Feeding a "protected feedlot supplement" to feedlot cattle and, thus, increasing the levels of. rumen bypass. long-chain fatty acids reaching the small intestine for adsorption, could have the potential to increase marbling. Glucose supply from both "bypass grain" and high rumen propionate levels, should be high on the largely high grain based diets fed to feedlot cattle. Preliminary experiments on small numbers of cattle (University of Queensland) indicated a potential for improving marbling by feeding protected lipid (PRIME). A large field trial of PRIME, at IeM Feedlot was not disappointing, but the trial had its complications and the level of protein in the diet was low. This low amino acid supply probably was rate-limiting in terms of a further response in marbling from the increased supply of long-chain fatty acids.