Effect of severity of early protein restriction on large turkey toms. 1. Performance characteristics and leg weakness.

The effect of early protein (Pr) nutrition on compensatory growth and leg weakness of turkey toms was studied. Four levels of dietary Pr [100, 80, 70, or 60% of National Research Council (NRC) recommendations in 1984] were fed ad libitum in isocaloric diets from 1 to 6 wk of age. Subsequently, the four treatment groups were fed a common diet within age periods according to NRC (1984) Pr levels. As the level of Pr decreased, body weight at 6 wk decreased (2.23, 1.94, 1.63, and 1.39 kg, respectively, P less than .005) and 1 to 6-wk feed:grain ratios increased. Weight gains from 6 to 20 wk of age were the same for all treatment groups. Thus, a significant carry-over effect of Pr on body weight was still evident at 20 wk of age (15.5, 15.2, 14.9, and 14.5 kg, respectively, P less than .005). Feed consumption decreased linearly through 16 wk of age as Pr decreased. Feed:gain ratios from 6 to 20 wk of age decreased (3.25, 3.20, 3.14, and 3.13, respectively, P less than .05), and Pr consumption:gain ratios from 1 to 20 wk decreased (.596, .551, .546, and .543, respectively, P less than .005) as the level of Pr decreased. However, the cumulative feed:gain ratio from 1 to 20 wk of age was not affected by Pr. The 60 or 70% level of dietary Pr resulted in 60% fewer toms with severe leg weakness at 18 wk of age than the 100% level of dietary Pr. Toms have limited ability for compensatory weight gain within the realimentation time allowed, regardless of the level of Pr fed from 1 to 6 wk. However, significant savings in dietary Pr and reduced leg weakness may be economically beneficial when Pr is restricted to 70% of the 1984 NRC recommendations during early growth.