A Comparison of Dimethoate Administered as an Injection and in Supplemental Feed for Control of Cattle Grubs1

Abstract

Hereford calves from Sweet Grass County, Montana were treated late in January with dimethoate for control of larvae of cattle grubs (Hypoderma spp.). The compound was administered either as a single injection at 10 mg/kg or for 10 days in a supplemental feed at 2 mg/kg/day. Intramuscular injection resulted in 81% control and low-level feeding in 79% control of cattle grubs. Of calves receiving dimethoate in the feed or as an intramuscular injection, 80% and 84%, respectively, had fewer than six grubs; however, 56% and 20%, respectively, were completely free of grubs. Of 25 calves receiving dimethoate in the feed only three harbored 60% of the grubs. It would therefore appear that some calves failed to take the supplemental feed, but in those which did, control was good.