Mastitis is the most costly and prevalent disease in the dairy industry, affecting the welfare of tens of millions of cows annually through painful udder inflammation that is frequently undertreated or inadequately managed.
Mastitis causes genuine and often prolonged pain. Clinical cases involve inflamed, swollen udder tissue that is painful to touch and during milking. Cows with mastitis show reduced feed intake, altered movement patterns, and behavioral indicators of pain. Subclinical mastitis is particularly concerning from a welfare perspective because it causes ongoing discomfort without obvious symptoms, meaning many affected cows go untreated. The high prevalence of mastitis in intensive dairy systems is partly a consequence of high milk yield selection that puts physiological stress on the mammary system beyond what natural udder physiology can sustain without consequences.