Face fly and horn fly activity in relation to daily beef cattle behavior and certain environmental factors

This study was conducted at the Plateau Experiment Station, Crossville, Tennessee. It was found that daily face fly populations varied greatly with cattle movement which affected horn fly populations to a lesser extent. Environmental factors showed little effect on daily face fly and horn fly population estimates. Face fly population peaks occurred at 11:30 A.M. and 2:50 P.M. on the average when cattle were in the shade. Horn fly populations did not necessarily peak at these times and there was much variation in the population throughout the day. Face flies declined 61.17 percent when cattle moved from the shade to the sun while horn flies declined 40.28 percent. Face flies and horn flies increased at a slower rate when cattle moved from the sun to the shade. At certain times during the day, face fly populations on herds without chemical control declined to fly population levels of those herds with chemical control. There were always more face flies and horn flies on cows as compared to calves.