Horn fly (Diptera: Muscidae) control and weight gains of yearling beef cattle.

Horn fly, Haematobia irritans (L.), populations were controlled on yearling cattle (n = 246) during the grazing season at moderate levels (68% control) with the use of organophosphate- and pyrethroid-impregnated ear tags. Weight gains of treated cattle during the 3-yr period were 17% greater than for untreated cattle. Results from this study demonstrated that yearling cattle of 25 or 50% Brahman, Bos indicus, breeding responded with improved animal performance in Louisiana when moderate horn fly control was achieved.