Sustained-Release Rabon Bolus for Face Fly Control in Cattle Feces12

Abstract

A sustained-release bolus containing 60% technical Rabon^® [2-chlorol-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate] was developed and shown capable of treating cattle feces for 184 days. Mature, fistulated Hereford heifers received either 1, 2, 4, or 6 Rabon^® boluses, and feces was collected from each animal on days 8 and 15 posttreatment for bioassay in a Latin-square design (4 by 4) against Musca autumnalis De Geer. Near complete control was achieved with the four- and six-bolus treatments by demonstrated mortalities of 96 and 99%, respectively. Complete control was not achieved due to passage of several boluses from the reticulum to the rumen. This resulted in reduced erosion rates, lower Rabon^® release, and thus lower larval mortality.