Feeding Broiler Breeder Males. 2. Effect of Cumulative Rearing Nutrition on Body Weight, Shank Length, Comb Height, and Fertility1

Two experiments were conducted to evaluate the effects of 2 planes (low and high) of cumulative nutrient intake during the rearing period on performance of broiler breeder males. The low cumulative nutrition program supplied 29,580 kcal of ME and 1,470 g of CP, whereas the high cumulative nutrition program supplied 33,500 kcal of ME and 1,730 g of CP to photostimulation at 21 wk of age. Two diets (LoDiet and HiDiet) were used with a single feeding program in experiment 1. In experiment 2, a single diet with 2 feeding programs (LoFeed and HiFeed) was used. In experiment 1, the 2 diets were blended from 21 to 24 wk to provide a gradual transition to a single common laying breeder diet that was fed during the production period. At 21 wk of age in experiment 2, males were divided into light or heavy BW groups to complete a 2 x 2 factorial design during the production period. The high plane of nutrition increased BW, shank length, and comb height during the rearing period, but the differences disappeared after 28 wk of age. Retrospective analysis showed that the heavy males at 21 wk of age in experiment 2 were also the heaviest males at 8 wk of age. Both low plane groups (LoDiet in experiment 1 and LoFeed in experiment 2) exhibited better fertility during late production. A cumulative nutrient intake during the rearing period of 29,580 kcal of ME and 1,470 g of CP was minimally sufficient for subsequent male reproductive performance.