Windpuffs are common fluid accumulations around horse fetlock joints that are usually benign but can indicate underlying joint or tendon sheath disease.
Windpuff assessment requires distinguishing between benign bilateral effusions in working horses - which cause no welfare harm and require no treatment - and unilateral or lameness-associated effusions that may indicate joint disease, tendon sheath inflammation, or early degenerative joint disease requiring veterinary attention. The danger of windpuffs is not the swellings themselves but the welfare harm of misclassifying pathological effusions as benign. A horse with unilateral fetlock effusion and subtle lameness that is dismissed as 'just windpuffs' may have undiagnosed joint disease causing ongoing pain. Regular veterinary examination including comparison between limbs, assessment of lameness, and ultrasound of any concerning effusions protects welfare by ensuring pathological conditions are not missed.