Suprascapular nerve paralysis (sweeney) causes shoulder muscle atrophy in horses from collar pressure or trauma, requiring specific management for welfare and recovery.
Sweeney causes visible, progressive muscle loss that affects the horse's movement and comfort. The shoulder instability resulting from muscle atrophy causes abnormal stress on adjacent structures, potentially causing secondary pain elsewhere in the limb and thorax. Horses working with unrecognized or unmanaged sweeney may experience ongoing discomfort from these secondary effects. Collar fit for working draft horses must be regularly assessed as the primary preventive welfare measure, and any horse showing unexplained forelimb weakness or shoulder muscle asymmetry should be promptly evaluated.