SAFETY OF ALBENDAZOLE IN DEVELOPING BOVINE FETUSES

Albendazole, administered orally at a dose rate of 25 mg/kg of body we ight to presumed pregnant cows or heifers on days 21, 31, 41, 51, and 61 of gestation, did not induce toxicosis in embryos or fetuses, and a ll calves born were structurally normal. Albendazole administration at a rate of 25 mg/kg to cows at 7 and/or 14 days of gestation decreased the apparent conception rate (ie, embryolethality), but did not have a teratogenic effect, Apparent embryolethality was greater in cows adm inistered 25 mg/kg only on day 14, compared with those administered th e drug only on day 7. Single dosage of 25 mg/kg given in the final 3 m onths of gestation did not induce abortion. There were no adverse effe cts of albendazole at a dosage of 10 or 15 mg/kg on developing embryos or fetuses when administered to presumed pregnant cows at various tim es in early gestation.