STUDIES OF BOLUS AND FEED FORMULATIONS OF TWO SYSTEMIC INSECTICIDES FOR REDUCTION OF CATTLE WARBLE INFESTATIONS, (OESTRIDAE: DIPTERA), IN BRITISH COLUMBIA, 1957–1958

摘要

In a series of bolus treatment tests, Trolene at dosages of 75?mg., and 110?mg. ronnel per kgm. of animal weight, and Narlene at 15?mg. nellite per kgm. reduced cattle warble, or larval Hypoderma infestations 91.2 per cent, 76.8 to 98.8 per cent, and 99.1 per cent respectively. There were no differences in the reductions produced by Trolene at dosages of 75 and 110?mg. per kgm. Narlene was preferable to Trolene for ease of administration. The labour requirements for treatment of a herd of 816 cattle of all ages and a group of 219 steer calves were 19 man-minutes and 10 man-minutes per animal respectively.In 25-day feed treatment tests, Trolene at 8 and 10?mg. ronnel per kgm. daily, and Narlene at 1?mg. nellite per kgm. daily reduced larvae 87.5 and 96.8 per cent and 91.0 per cent respectively. Feed treatment eliminated the labour and equipment required for bolus treatment.In a test of Trolene boluses there was no difference in the 22-week post-treatment gains of treated and untreated yearling steers, even though larvae were reduced 86.5 per cent.Trolene bolus treatment did not appear to aggravate active coccidiosis epidemics and active coccidiosis did not appear to reduce the efficiency of Trolene treatment.These tests were co-ordinated with British Columbia range management practices. Although these practices seldom permit treatment until much later in the season than is recommended for systemic insecticides, the test results are fully comparable to those reported from areas where the recommendations can be adhered to.