Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 1994
Publication Date: N/A
Interpretive Summary: There is considerable interest in production of leaner carcasses due to consumer demand for leaner meat products. Restricted feeding of the animal may be an approach to producing leaner carcasses, providing one avoids depressing the feed efficiency of the animal. This study examined the effects of restricted feeding of all concentrate (corn) diets on performance and carcass composition of lambs. Results indicate that restricting daily intake of an all concentrate diet leads to lower daily gains, yet has no effect on feed efficiency. The lower daily gains result in reductions in carcass fat accretion in the subcutaneous, seam, internal depot sites as well as the intramuscular site which is the one that gets consumed. Based on these results, it appears that restricted feeding strategies can lead to the production of leaner carcasses.
Fifty-eight crossbred lambs (26 kg BW) with moderate growth potential were used in a completely randomized design to determine the effects of restricted feeding of all concentrate diets on performance and carcass composition. Feeding levels studied were 100, 85 and 70 percent of ad libitum intake. Diets were formulated to provide equal daily intakes of protein, vitamins, and minerals among DM intake levels. Lambs were fed to a final weight which would yield carcasses of equal weight (24 kg). Average daily gain was reduced linearly and days on feed were increased linearly because of restricted feeding. Feed efficiency, however, was not affected by intake level. The quantity of separable lean tissue within carcass sides was increased with restricted feeding. Total separable fat within the side was reduced in an amount equal to the increase in lean tissue accretion. Daily accretion rates of lean and bone tissue were not affected by restricted feeding, however, fat accretion was decreased linearly with decreasing feeding levels. Separable lean tissue within the primal cuts was generally increased with decreasing intakes which led to a corresponding decrease in separable fat. Chemical analysis of the lean tissue from each of the primal cuts showed a decrease in intramuscular fat content of the lean for the leg, loin and breast with no effect on the rack and shoulder. Restricted feeding strategies can lead to the production of leaner carcasses. Reductions in fat content occur in the subcutaneous, seam and mesenteric depot sites, but intramuscular fat content of consumable product also is reduced.