Ferket P R, Sell J L
Department of Animal Science, Iowa State University, Ames 50011.
Poult Sci. 1989 May;68(5):687-97. doi: 10.3382/ps.0680687.
The effect of early protein (Pr) nutrition on the carcass characteristics of turkey toms was studied. Four levels of dietary protein [100, 80, 70, or 60% of National Research Council (NRC) recommendations in 1984] were fed as isocaloric diets ad libitum from 1 to 6 wk of age. Subsequently, the four treatment groups were fed according to NRC recommendations in 1984 to 20 wk of age. Toms from all treatment groups were sampled at 6, 12, and 20 wk of age, and New York-dressed carcasses were evaluated for chemical composition and yield of commercial cuts. Fat and DM content in the carcass increased, whereas ash and crude Pr content decreased as the toms aged. Yields of breast and back increased, drumsticks and wings decreased, and thighs did not change as the toms aged. At 6 wk, percentages of carcass Pr and ash were not affected by Pr, but fat increased linearly as the level of Pr decreased (P less than .005). Breast and thigh meat yields decreased, and skin yield increased as the level of Pr decreased. Yields of bone and other carcass parts were not influenced by Pr. At 12 and 20 wk, breast and thigh meat yields and chemical composition were restored to normal proportions, irrespective of early Pr nutrition. At 20 wk of age, only breast yield was significantly reduced by 60% Pr (P less than .05). The amount of dietary Pr consumed per carcass Pr gain decreased at all stages of growth as the level of Pr decreased. Early Pr had minimal effects on relative organ weights. Toms recover from the effects of early Pr restriction on carcass parts, but restriction to the 60% level may reduce breast meat yield.