Chemical Control of Ticks on Cattle

Abstract

Chemicals are an important part of efforts to control ticks on cattle. They can be grouped by their origin or chemical structure as plant extracts, organochlorines, organophosphates, carbamates, formamidines, synthetic pyrethroids, and macrocyclic lactones. Their efficacy has been proven by means of a variety of in vitro and in vivo test methods. Topical application of aqueous formulations by means of plunging or spraying has been the principal means of treatment for many years. Innovative, labour-saving formulations, such as pour-ons, injections and impregnated devices, have been developed over the last few years. As is the case with most chemicals used for pest control, ticks that are resistant to the majority of the different classes of acaricides, have been described from various parts of the world. Although Boophilus spp. are the prime culprits, multi-host ticks also display this ability. The benefits that are derived from chemical control ofthe harmful effects ofticks, can be offset by other factors, such as toxicity of the chemical, production losses from handling ofthe animals, and the direct cost of the chemical.