Internal parasites cause significant welfare harm in cattle. Evidence-based targeted treatment approaches improve animal welfare while reducing anthelmintic resistance development.
Cattle parasite management balances individual animal welfare against the long-term welfare consequences of anthelmintic resistance development. Heavily parasitised animals suffer from diarrhoea, weight loss, anaemia, protein deficiency and in severe cases death. Untreated parasite burdens cause significant chronic welfare harm. However, blanket prophylactic treatment is accelerating resistance development that could render effective treatments unavailable in future — a long-term welfare threat that outweighs short-term treatment convenience. Targeted selective treatment, using indicators of individual animal burden to guide treatment decisions, maintains welfare of heavily burdened animals while reducing selection pressure for resistance. Integration of pasture management, genetic selection for parasite resistance and strategic targeted treatment represents the most welfare-positive long-term approach.