Response of large white turkeys to virginiamycin from day-old to slaughter

Diets containing 0 or 22 mg of virginiamycin per kilogram were fed to 448 Nicholas Large White turkeys from day-old to slaughter at 16 (females) or 20 wk of age (males). Weight gain of males, but not females, fed treated diets increased significantly from 0 to 4 and 4 to 8 wk of age, but not in later periods. However, final weights of both sexes were increased by treatment with virginiamycin. Feed efficiency of treated birds increased to 8 wk of age but not overall. Mortality and carcass finish and fleshing scores were unaffected by the antibiotic treatment.