DAILY ENERGY ALLOTMENT AND REPRODUCTIVE-PERFORMANCE OF BROILER BREEDER MALES

Ross broiler breeder males, housed in floor pens with females and fed from separate feeders, were given 125 g/day of isonitrogenous diets formulated to provide 300, 340, and 380 kcal per male per day between 28 and 60 wk of age. Males given 300 kcal/day maintained their initial BW and were consistently lighter than those fed the two higher energy levels; BW of males given the two higher energy allotments did not differ from each other. Fertility levels, over the whole experiment, averaged 80.1, 91. 1, and 83.0% for the low-, intermediate-, and high-energy groups, respectively. Fertility dropped slightly over time in all groups but showed a precipitous fall in the low-energy group between 48 and 60 wk. Hatchability of fertile eggs showed a significant decrease over time but no treatment differences were found. Hatchability of eggs set, like fertility, showed a significant quadratic regression on energy allocation. A significant linear effect of energy level on 60-wk testes weights was found but carcass composition at 60 wk was unrelated to dietary energy allocation. Males fed 300 kcal/day had less severe pododermatitis than males in other groups, but the correlation between BW and pododermatitis score was not significant. Average 6-wk BW of approximately 500 offspring of males fed the low-energy diet, raised comingled with those from other male treatments in three separate growth trials, were consistently and significantly lower than those of offspring of males fed 380 kcal/day.