First report of annual ryegrass toxicity in the Republic of South Africa.

The occurrence of annual ryegrass toxicity (ARGT) in sheep and cattle is reported for the first time in South Africa. To date it has been diagnosed conclusively in South African Mutton Merino sheep on a farm in the Caledon district and in cattle on 3 farms, 2 of which are situated in the Bredasdorp district and 1 in the Ceres district. It is a neurological disease characterized by symptoms of tremor, ataxia, intermittent epileptiform seizures, nystagmus, opisthotonus, abortions and high mortality. The history, clinical signs and experimental reproduction of the disease as well as the pathology of 4 experimental and 10 natural cases in sheep and 2 in cattle are described.