Tail docking of dairy cows was historically common but has been largely banned in developed countries following evidence that it provides no welfare benefit and causes significant harm.
Dairy cattle tail docking is a welfare intervention with no scientific support that was practiced for decades based on intuition rather than evidence. When systematic research examined whether tail-docked cows had better udder hygiene or lower mastitis rates, no benefit was found. The welfare harms — acute pain from docking, chronic pain during healing, and permanent loss of a functional fly-swatting appendage — have no welfare benefit to justify them. Progressive bans based on this evidence represent animal welfare policy operating as it should: responding to scientific evidence by removing a harmful and unnecessary practice.