Unilateral spastic paresis: caudal neurectomy

Holstein heifer calf approximately 4 months old with hyperextension of the hock joint of the left hind limb (video).
Spastic paresis is a rare neuromuscular disorder of probable hereditary origin, characterized by progressive and uncontrolled unilateral or bilateral hyperextension of the hock and stifle joints, due to spastic contraction of the caudal tibial muscles (lateral and medial gastrocnemius). It can affect calves of various cattle breeds, both male and female, generally between 2 and 8 months of age.