In Practice 26: 538-547 (2004)
© 2004 British Veterinary Association

Therapies for ectoparasiticism in sheep

¹ Veterinary Laboratories Agency (VLA), Weybridge; Sheep Veterinary society,The Goat Veterinary Society and The British Association for Veterinary Parasitology.

A NUMBER of ectoparasites can affect sheep in the UK, with potentially serious consequences. Production can be severely affected, in terms of reduced milk and meat yields, downgrading of wool and leather, and the need for expensive control programmes. Ectoparasitic infestations also significantly compromise the welfare of flocks and individual sheep, and may result in prosecutions for animal cruelty. Effective control depends on whether the ectoparasite is permanent (ie, spends its entire life cycle on sheep) or semipermanent (ie, has at least one free-living stage). This article describes the various classes of ectoparasiticides and how they may be applied to animals for best effect. In view of concerns over resistance and pesticide safety, which may have implications for future product availability, it also outlines some alternative methods of control which might be implemented instead of, or in combination with, traditional ectoparasiticides.