Stringhalt is a neurological condition causing involuntary hind limb flexion in horses, ranging from a cosmetic gait abnormality to severely disabling hyperflexion requiring euthanasia.
Horses with severe stringhalt experience a frustrating inability to control their own limb movement — violent hind limb jerking disrupts normal locomotion and causes falls that risk injury. The muscular effort involved in constant abnormal flexion causes fatigue and muscle soreness. Affected horses may become anxious about movement, particularly on hard surfaces where the jerking is most pronounced. Australian stringhalt outbreaks on shared pastures can affect multiple horses simultaneously, overwhelming farm management capacity. The uncertainty of prognosis — some cases resolve, others progress — makes welfare decision-making difficult for owners. Horses that cannot move normally, eat comfortably, or rest without risk of falling from limb jerking have severely compromised welfare that may require euthanasia.