DURATION OF FECAL EGG COUNT REDUCTION FOR ANTIPARASITIC COMPOUNDS IN THE YOUNG HORSE

A total of 48 weanlings and yearlings were used in a study designed to address the efficacy of anthelmintic use 3 to 8 weeks following treat ment. The eight different antiparasitic compounds tested included, eit her individually or in combination, anthelmintics from seven of the kn own classes of antiparasitic compounds. It was found that duration of reduction in EPGs varies greatly depending on the antiparasitic compou nds being used. Because of this, formulations from any of the known cl asses of antiparasitic compounds need to be tested regularly on animal s in the geographic region in which they are being used.