Expar 1% Pour-On for Lice Control on Beef Cattle, 1987

Abstract

Abstract Experimental steer and heifer calves of mixed breeds and originating in eastern Wyoming were housed in separate pens in groups of 6 animals each. The cattle in one pen served as untreated controls. The cattle were naturally infested with the cattle biting louse, Bovicola bovis (Bb), the longnosed cattle louse, Linognathus vituli (Lv), and the little blue cattle louse, Solenopotes capillatus (Sc). The hair was parted and louse density was estimated by observing and recording the number of each species at sample sites on the host. The body regions examined were one 5- X 15-cm area on the topline, one 5- x 15-cm area on the withers, two 10- X 15-cm areas surrounding the right and left eyes, two 5- x 10-cm areas on the right and left cheeks, one 5- x 25-cm area on the muzzle, and one 5- x 15-cm area on the dewlap. Following pretreatment louse counts, the animals were ranked according to louse density and divided into pairs of approximately equal density. The members of the pairs were then assigned randomly to either the Expar 1% Pour-On treatment or to an untreated group. Expar 1% was applied according to label directions. Undiluted insecticide was poured along the back and down the face of each animal at 0.5 fl oz/100 lb body weight of animal on 9 Mar and again on 23 Mar.