Antiparasitic resistance and grazing livestock in the United States

摘要

Antiparasitic resistance, specifically resistance to anthelmintics among gastrointestinal parasites of cattle, small ruminants, and horses, is both a health and a welfare issue for US grazing livestock and potentially threatens animal agricultural production. The veterinary community broadly accepts that antiparasitic resistance is widespread among small ruminant parasites, particularly in Australia, New Zealand, South Africa, and some South American countries. And, many veterinarians and livestock producers acknowledge that antiparasitic resistance is also a problem among small ruminant parasites in the United States. However, awareness of antiparasitic resistance in cattle and horse parasites in the United States and other countries is relativelylow, even while reports of resistance involving parasites of these species are increasing. Although the FDA Center for Veterinary Medicine (CVM) determines whether antiparasitic drugs for animals are safe and effective before approval, the drugs' continued effectiveness after approval largely depends on how they are used by veterinarians and producers.