The Weight Responses of Beef Cattle in Relation to Control of Horn and Stable Flies1

Abstract

Repellent-insecticide oil formulations were tested in a treadle sprayer for the control of biting flies (predominantly Siphona irritans (L.) and Stomoxys calcitrans (L.)) on grazing beef cattle (weighing from 600 to slightly over 900 pounds) for three summers at the Rosemount Agricultural Experiment Station of the University of Minnesota, 1954-56, with the following results: (1) In 1954 and 1955, significant weight gains were realized on cattle which had been treated to reduce the number of biting flies. The lower gain in weight in the treated cattle in 1956 may have been due to cool temperatures, abundant rainfall and a resultant excellent forage crop. (2) Control of horn flies exceeded 95% and reduction in numbers of stable flies was about 70%. (3) Pyrethrins plus piperonyl butoxide or MGK-264 gave satisfactory fly control, but the addition of butoxy polypropylene glycol to the formulation permitted a reduction in quantity of pyrethrins content without loss of efficiency. (4) Individual animals, within a breed, had greater variations in numbers of biting flies than occurred between breeds. (5) On the basis of these results, and a study of weather records, a profitable return from biting fly control may be expected in most years.