| Abstrakt: |
Large White male turkeys were raised to 20 wk of age on diets with varying kinds and levels of coccidiosis drug protection. Dietary treatments included unmedicated control (UMC), amprolium (AMP, 125 mg/kg), and 3 levels of halofuginone hydrobromide (HAL, during 0 to 4 and 4 to 8 wk of age, in 3.3; 3.1.5; and 1.5,1.5 mg/kg, respectively). Turkeys on these five treatments were exposed to coccidial oocysts at 14 days of age and again at 61 days of age; turkeys in an identical five treatments were not exposed until 61 days of age. At 28 days, nonexposed turkeys gained well and similarly, whereas exposed UMC showed poor growth and high mortality. At 56 days, regardless of exposure, UMC were lightest, AMP birds were intermediate, and birds in all HAL treatments were heaviest. Similarities in results of exposed and nonexposed birds suggests that nonexposed birds became exposed through tracking of oocysts in the room. Lesion scores of those challenged with oocysts at 61 days showed that all treatments had adequate resistance to coccidiosis. At 20 weeks of age, combining both exposure methods, birds fed HAL (dosage 3.1.5 or 1.5, 1.5 mg/kg) were significantly heavier than UMC and AMP treatments. |
