Studies of Bolus and Feed Formulations of Two Systemic Insecticides for Reduction of Cattle Warble Infestations, (Oestridae: Diptera), in British Columbia, 1957–1958

Abstract

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.

Free-Choice Feeding of Trolene for Reduction of Cattle Warble Infestations (Oestridae: Diptera)

“…and Ireland (7) previously discussed the problems associated with treatment of cattle herds on ranches in the interior of British Colurnbia with systemic insecticides for control of the catde warbles, Hypoderma bovis (L.) and H. lineatum (De Vill.). The economics of ranch management frequently require that cattle remain dispersed on the ranges until early or mid-winter; thus in many instances treatment for lice and warbles cannot be applied until the weather is so cold that administration of the insecticide by mouth is the only practical method.…”

“…French et al (2) fed 35 milligrams per kilogram daily for 6 days to 28 steers and reported a reduction of 97.8 in grub numbers. Rich and lreland (7) SDow Chemical Compmy trade-nme for veterinary imecticide fomulations containing O, O-dimethyl O-(2, 4, S-trichlorophenyl) phosphorothioate, formerly knom m "Dw. ET57".…”

An Appraisal of Ruelene and Trolene Against Cattle Grub Infestations, (Oestridae: Diptera)

“…-dailv for-5 davs. and feeding Trolene at I5 mg'/kg' daily tor 7 an{tz?ays, ieduced th6 numbers of g-rubs by 95,-94,-94 Rich and Ireland (6), and Rich (7) …”