Two trials were conducted to evaluate the effects of feeding various anticoccidial products to turkeys to 8 wk and then growing to market age (16 wk for hens and 20 wk for toms). Anticoccidials evaluated in the first trial included amprolium at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; butynorate at 375 mg/kg for 0 to 8 wk; monensin at both 60 (MON-60) and 100 mg/kg for 0 to 8 wk; zoalene at 187.5 mg/kg for 0 to 4 wk and 125 mg/kg for 4 to 8 wk; and halofuginone at 3 mg/kg for 0 to 8 wk. In the second trial, MON-60 was replaced by a combination of sulfadimethoxine (62.5 mg/kg) plus ormetoprim (37.5 mg/kg) for 0 to 8 wk. In each trial each treatment was fed to four pens of 16 hens and four pens of 12 toms. Several of the anticoccidials significantly influenced the weight of both hens and toms by producing lower weights at the end of the 8-wk feeding period than birds in other treatments. However, after removal of the anticoccidials, compensatory gains were observed in almost every instance. Significant effects of previous anticoccidial feeding were noted on body weight of hens at 16 wk but not on weights of toms at 20 wk.
