The delivery of medications through feed in salmon farming is a primary treatment route but raises welfare questions about dosing accuracy, palatability, and stress during treatment periods.
In-feed medication delivery creates welfare complications beyond the disease being treated. Reduced palatability of medicated feed leads to hunger in fish who stop eating, while inconsistent intake means some individuals receive subtherapeutic doses and remain ill. Dominant fish may consume disproportionate amounts leaving subordinates undertreated. The cumulative stress of disease, appetite suppression, and social disruption during treatment periods represents significant welfare cost. Preventive approaches that reduce disease incidence - particularly vaccination programmes - dramatically reduce the welfare burden of treatment cycles.