Hairy shaker disease of lambs

Abstract

Extract

Records from New Zealand diagnostic stations reveal that, at least since 1957, a syndrome in lambs has been encountered which is characterized at birth by excessively hairy fleeces and fine muscular tremors of head and limbs which are often severe enough to cause inco-ordination. These features have given rise to the apt colloquial name of hairy shaker disease. The condition was first reported by Hartley and Kater (1962). Histological examination of the central nervous system usually reveals hypomyelinogenesis which is most marked in the spinal cord and affects all columns of white matter. Some lambs may have a hairy fleece but do not show nervous signs or histological evidence of hypomyelinogenesis. Hairy lambs with and without chorea appear to have a low survival rate and may die within two or three months. Others survive but have a slow rate of growth. If nervous signs are present they tend to regress over a period of several months. The condition has been seen in Romney × Romney, Southdown × Romney, Border Leicester × Romney, Cheviot × Romney, and South Suffolk × Romney lambs but, to date, not in fine wool breeds. It is widespread in the South Island and has also been seen in the northern half of the North Island (Fig. 1). Hughes et al. (1959) described a very similar condition in the United Kingdom and called it Border disease because it was first seen on the border of England and Wales.