Effect of Horn Flies on Weight Gains of Beef Cattle123

Abstract

Haematobia irritans (L.) was controlled by exposing yearling steers to dust bags containing 1% coumaphos installed at entrances to salt box enclosures. Weight gains of treated steers during 6 yr, 1971–1976, increased an avg of 5 and 3 kg/head more than untreated steers during early and late grazing periods, respectively. The total gain advantage for horn fly control at time of slaughter, following a feedlot phase, was 10 kg/head.