Ryegrass Staggers
February 2024

Ryegrass staggers is a disease caused by a fungus which can grow in perennial ryegrass producing a compound toxic to the nervous system. The fungus is found in all areas of the plant but mostly concentrates in the seed head and base of the leave in the grass. Clinical signs will usually develop within 2-3 days of ingesting the pasture.

The main clinical signs seen closely resemble a “drunken” animal including:

  • Muscle and head tremors
  • Incoordination
  • Decreased production and loss of condition
  • Heat stress and dehydration

Unfortunately, there is no specific treatment, but supportive care is required. It is important to remove the animals from the affected pasture but vital to reduce their stress while doing so to avoid collapse. Affected stock can suffer from misadventure through drowning and getting caught in hazards, so ensure they are put in a safe paddock.


  • Remove animals from affected pasture immediately and provide alternative feed
  • Provide shade and fresh water

Diagnosis is usually made through clinical signs along with diet and the recent weather conditions. It is common to find multiple animals affected if they are eating the same pasture.

Prevention requires avoiding overgrazing so the animals cannot eat to the base of the grass and cut hay or baleage before the plant can flower to help minimize the toxin in the plant. Mixing your pasture with other grass species and legumes will also help to reduce intake of the fungus.

There are plenty of toxic plants/substances that can cause these clinical signs and may require different treatments so give your vet a call if you are concerned so we can make the correct diagnosis and help your animals to recover as soon as possible.