Parasite prevention is essential for dog welfare, but the choice of products involves balancing effectiveness, safety, and environmental impact in an evidence-based way.
Effective parasite control is fundamental to dog welfare — flea allergy dermatitis causes intense suffering, heartworm disease causes progressive cardiopulmonary damage, and tick-borne diseases can be debilitating or fatal. However, parasite prevention products carry their own risk profiles: isoxazolines have neurological side effects in a small proportion of dogs; spot-on permethrin products are lethal to cats and toxic to aquatic organisms; and heavy anthelmintic use contributes to drug resistance. Welfare-conscious prevention involves choosing products appropriate to individual risk profiles, using environmental control, and avoiding unnecessary chemical exposure.