Abstract:
Outbreaks of clinical disease caused by the ingestion of ergotized Lolium rigidum (annual ryegrass),
which resulted in a substantial loss in production, have been reported. A number of outbreaks of a hyperthermia
syndrome in cattle, characterized by severe loss in milk production, loss of body mass and
reduced fertility, are described. In one major outbreak in March to April 1994, a milling company reported
that 2 646 dairy cows on 29 farms had developed clinical signs. In this outbreak, significant levels
of ergotamine, ergosine, ergocornine and ergocryptine were found in the milled dairy rations fed to
the affected cows. Barley screenings containing ergotized annual-ryegrass seed was identified as the
toxic component and probable source of the ergot alkaloids in the ration. The clinical syndrome was
reproduced experimentally by feeding suspected feed to a group of nine high-producing Ayrshire cows.
An outbreak of gangrenous necrosis of the extremities in young cattle in the winter of 1987 was also
suspected of having been caused by ergot alkaloids in grain screenings.
