THE EFFICACY OF EPRINOMECTIN AGAINST INDUCED INFECTIONS OF IMMATURE (4TH LARVAL STAGE) AND ADULT NEMATODE PARASITES IN CATTLE

Eprinomectin is a new endectocide of the avermectin chemical group dev eloped for use in cattle. To establish its effectiveness against Coope ria spp., Dictyocaulus viviparus, Haemonchus contortus, Nematodirus he lvetianus, Oesophagostomum radiatum, Ostertagia ostertagi, Tri chostro ngylus axel and Trichostrongylus colubriformis (immature infections on ly), six trials were conducted in Europe at two trial sites. In each t rial, animals were artificially infected with a number of nematode spe cies and treated with eprinomectin. In three trials, the nematodes wer e expected to be at the fourth larval stage of development at the time of treatment, and at the adult stage at the time of treatment in the other three trials. When compared with the untreated control groups, e fficacy against the adult and immature nematode infections was > 99% f or all the nematode species examined. There was no difference in effic acy between groups of animals with clipped hair at the application sit e, and those with long hair. Subsequent examination of the application sites, both visual and by palpation, showed no gross reactions to the applied treatments. (C) 1997 Elsevier Science B.V.