Resistance to antiparasitic drugs in livestock is growing rapidly, limiting treatment options and increasing disease burden. Sustainable parasite management protects animal welfare and treatment effectiveness.
Antiparasitic drug resistance threatens the effectiveness of treatments that prevent significant suffering in livestock. Parasitic gastroenteritis and liver fluke cause chronic pain, reduced productivity, and death in inadequately controlled infestations. As resistance to available drugs increases, treatment options narrow and parasite burdens increase, causing greater welfare harm. The welfare-positive response to resistance involves responsible use — targeted selective treatment based on diagnostic evidence rather than blanket preventive treatment — combined with pasture management strategies that reduce parasite exposure. This approach slows resistance development while maintaining welfare through selective treatment of high-burden animals.