Increased risk of perennial rye-grass staggers this autumn

The very dry summer, followed by a wet start to autumn, has increased the risk of perennial rye-grass staggers and poses a risk to grazing animals – cattle, sheep, horses and camelids.

Perennial rye-grass (Lolium perenne) can become infected with an endophytic fungus which produces mycotoxins when ingested by grazing animals; this can cause perennial rye-grass staggers, also referred to as perennial rye-grass toxicosis.

Clinical signs

Animals can develop a variety of clinical signs, which usually develop 2–3 days after ingestion of toxic amounts.

These may include:

• Decreased feed intake and reduced productivity
• Increased time seeking shade and water
• Muscle tremors
• Stiff or irregular movement
• Weakness
• Dehydration
• Heat stress (panting or drooling in hot weather)
• Collapse
• Death (due to heat stroke or misadventure)

Contact your vet for advice as diagnosis is based on clinical signs, history of grazing perennial rye-grass and ruling out other causes.

Treatment

Contact your vet for advice in the first instance.

Separate affected animals from the rest of the herd/flock and situate them in a quiet area to minimise stress with access to fresh water to prevent dehydration and heat stress.

The remainder of the herd/flock should also be moved from the potentially affected grazing area.

Mildly affected animals usually recover within several days after the affected forage is removed. Animals that are more severely affected can take longer to recover.

You should be able to return livestock to the pasture in a few weeks once it has regrown, but speak to your vet to discuss the best course of action.

Prevention

Using mixed swards, i.e.planting other grasses and legumes within rye-grass pastures, reduces the intake of affected rye-grass and, therefore, minimises the potential impact on animals.

Use good grazing management practices – prevent overgrazing and cut hay or baleage before the plants flower to minimise concentrations of mycotoxins in the forage, even when the endophyte is present.

Consider planting perennial rye-grass strains that reduce the risk of this mycotoxin.