Effect of chemoprophylaxis on immunity to gastrointestinal nematodes in cattle.

Control of gastrointestinal nematodes in calves is largely based on either strategic anthelmintic treatment or the use of anthelmintic-release devices. Control is evolving towards more efficacious anthelmintics and delivery systems, almost annihilating host-parasite contact. Recent studies have demonstrated the inverse relationship between the intensive use of modern anthelmintics and the build-up of immunity to gastrointestinal nematodes. A study performed by the Department of Parasitology, Faculty of Veterinary Medicine, Merelbeke, Belgium did provide further support for the finding that the development of immunity can be impaired by the implementation of preventive control measures.