BOVINE ASYMMETRIC HIND-LIMB PARESIS, A PRESUMPTIVE IN-UTERO PLANT POISONING

A new locomotory disturbance of cattle is described. The condition has occurred sporadically since the mid-1980s. Affected herds had all gra zed flood plain pastures in a restricted area of north-western New Sou th Wales. Calves were either born with clinical signs or developed the m by 4 months of age. The disease was characterised by a slowly progre ssive, irreversible, asymmetrical, paresis of the hind limbs. Affected cattle experienced persistent hyperextension of the hip and stifle jo ints. Macroscopic and microscopic examination of the nervous and muscu loskeletal systems failed to demonstrate abnormalities that would acco unt for the clinical signs. The disorder shares many similarities with bovine spastic paresis. It is suggested that the pathogenesis of the disorder is nervous, and probably involves nigro-striatal, medulla obl ongata, and spinal dysfunctional inputs. An in-utero plant poisoning w as suspected but no specific plant association was determined.