SULFUR-INDUCED POLIOENCEPHALOMALACIA IN LAMBS

An outbreak of polioencephalomalacia affected 16 of 46 Swaledale lambs and five of 25 Scottish blackface lambs 15 to 32 days after they were introduced to an ad libitum concentrate ration containing 0 . 43 per cent sulphur. The clinical signs were acute and included depression, c entral blindness and head-pressing, but no hyperaesthesia, nystagmus, dorsiflexion of the neck or opisthotonos were observed. Treatment of t he affected lambs with vitamin B-1, dexamethasone and antibiotics was associated with a prolonged recovery period, though no further cases w ere identified after vitamin B-1 had been given parenterally to all th e lambs at risk.