This abnormality of neonatal piglets is characterized by lateral extension of the hind legs with inability to adduct the legs; front legs may be variably affected. The principle lesion in affected muscles is myofibrillar hypoplasia related in part to delayed development, and in part to degenerative change.
Proposed causes or suggested risk factors include a genetic predisposition, slippery or sloped floors, porcine stress syndrome (PSS) in the parents, dietary deficiencies, and low birth weights or tremors in piglets.
If affected piglets are helped to nurse and protected from accidental injury by the sow, many will recover in one to two weeks. Tying the front legs or the back legs loosely together with sticky tape will increase the likelihood of survival. Selection of breeding stock with no tendency to produce affected litters will reduce incidence.