Resistance to anthelmintic drugs is growing globally in livestock parasites, threatening the effectiveness of the primary tool for managing parasite-related welfare harms in sheep, goats, and cattle.
Anthelmintic resistance threatens to return livestock parasite management to the pre-drug era, with potentially severe welfare consequences. Animals with high parasite burdens experience anemia, malnutrition, and in severe cases death. Integrated parasite management strategies that combine targeted treatment, refugia maintenance, nutrition, and selective breeding for resistance represent the sustainable welfare solution. Preserving drug efficacy is itself a welfare investment.