AN EVALUATION OF FENVALERATE (BOVAID) EARTAGS AS AN IMPROVEMENT IN FLY CONTROL METHODS FOR INCREASED MILK PRODUCTION IN DAIRY HERDS

Abstract
A field study was conducted on 60 cooperating dairy farms in Southwestern Ontario to determine the effect of fenvalerate-impregnated (8% wt/wt) eartags (Bovaid (Registered trademark CIBA-GEIGY Canada Ltd.)) on fly control and milk production. Herds were assigned to either a tagged or control treatment. Fly counts were made on 15 randomly selected cows in each herd at approximately 2-wk intervals from July to September. Producers of control herds in this study conducted normal management practices including, in most cases, conventional fly control methods. Therefore, the comparison in this study is between the fenvalerate-impregnated tag and more conventional means of fly control. Milk production data were obtained from DHIC and Ontario Milk Marketing Board records. The use of the Bovaid tag resulted in complete control of horn flies (Haematobia irritans) and a 75% reduction in face flies (Musca autumnalis) over the test period. Milk production was not significantly affected by treatment although a 2–3% improvement was observed in treated animals. A milk production effect of 7% would be required for statistical significance (P < 0.05). Key words: Fenvalerate, ear tags, fly control, milk production