Further Observations on the Effect of Biting Fly Control on Milk Production on Cattle12

Abstract

Promising results obtained in 1955 led to an expansion of tests in 1956. On 2 farms a water emulsion formulation containing methoxychlor was applied once a week to one-third of the herds, and a formulation containing methoxychlor plus butoxy polypropylene glycol (Crag Fly Repellent) to another 3d of the herds; the rest of the animals were left untreated. There was a marked difference between treated and untreated groups, both in reduction in fly annoyance and increased milk production. On a 3d farm where the sprays were applied twice a week results were similar but not enough data were secured to determine whether an additional spray per week is warranted. Butoxy polypropylene glycol tended to increase the effectiveness of the formulation in which it was an ingredient. Wettable powders containing methoxychlor or methoxychlor plus butoxy polypropylene glycol were applied to groups of animals on a 4th farm as dry powders or as sprays. Both dust treatments were superior to no treatment but at the concentrations used the fly repellent did not increase the effectiveness of the methoxychlor. Increased milk production by cows receiving the wettable powders applied as sprays was not evident in these tests. Monetary returns above the cost of the emulsion spray treatments were greater in 1956 than in 1955.