Increased Risk of Perennial Ryegrass Staggers this Autumn

Perennial ryegrass.

The message below was circulated by APHA’s Emerging & Endemic Disease Alert System and we thought it useful to circulate it further.

The very dry summer followed by a wet autumn will increase the risk of this neurotoxicosis in cattle, sheep, camelids and horses.  APHA has received a recent anecdotal report of the condition affecting lambs near Bristol.

The risk is to animals grazing perennial ryegrass (Lolium perenne) infected with an endophytic fungus.

Clinical signs usually develop within 2 -3 days after ingestion and include muscle tremors, stiff or spastic gait, heat stress, collapse and recumbency. Diagnosis is based on clinical signs, history of grazing perennial ryegrass and ruling out other differential causes.

There is no treatment and affected animals should be removed and separated in a quiet area, while the remainder of group taken off the risk grazing. The animals can be returned to the affected pasture once regrown in a few weeks.

Posted by SRUC Veterinary Services on 17/09/2025