Effects of feeding program and crude protein intake during rearing on fertility of broiler breeder females

Abstract

Arbor Acres broiler breeder pullets were grown from hatch to 24 wk on one of four feeding programs that achieved similar cumulative intakes of ME and CP at 24 wk, but not 20 wk (photostimulation), in Experiment 1. Graphing the four programs in terms of feed per bird per day by week of age gave the general shapes of linear, convex, concave, and deeply concave with respect to 0 and 24 wk reference points. The linear program, which achieved 1,192 g CP at 20 wk (photostimulation), as compared to < 1,150 g CP for the two concave programs, exhibited the best fertility. Although the pullets reared on the convex program consumed 1,255 g CP, fertility was poor, probably due to the reduced rate of increase in feed allocation late in rearing that delayed oviduct development. In Experiment 2, pullets were fed to the same cumulative ME intake at 20 wk using either a concave or convex feeding program with respect to 0 and 20 wk reference points with two levels of dietary protein. The higher level of CP intake (1,363 vs 1,212 g) produced higher fertility. A significant feeding program by dietary protein interaction was found. Level of CP intake at photostimulation had no effect on fertility with the concave feeding program but the convex program decreased fertility at the lower CP intake as in Experiment 1.