Urgent warning to farmers to prevent annual ryegrass toxicity in livestock as issue spreads to the South West

A well-known WA vet has urged farmers to closely monitor sheep, cattle and horses for signs of annual ryegrass toxicity as a perfect storm of weather conditions cause cases to increase for the second year in a row. Department of Primary Industries and Regional Development vet Anna Erikson said the disease was most common in the Wheatbelt, but cases were now being reported in the South West and along the coastal plain. Annual ryegrass toxicity is a serious and usually fatal disease that occurs when livestock eat annual ryegrass seedheads infected with a toxin-producing bacterium, accumulating in the animal’s system. Signs of ARGT in sheep, cattle and horses include shaking, clumsy gait, jaw champing and dullness, followed by an inability to rise, convulsions and in severe cases, death. The symptoms are made worse by stress or movement. Dr Erickson said this year’s conditions had been ideal for the development of ARGT, similar to last season. “I have investigated five cases in recent months and carried out pre-emptive pasture testing for many more,” she said. “Many of those tests have come back positive.” Stock owners and feed sellers with hay containing annual ryegrass should have it tested for toxicity before they sell it or feed to stock. Dr Erickson advised against buying untested hay. “It’s important to remember that even if you live in a lower risk area, the hay you buy may have been grown in a different region and could be infected,” she said. “Provided the samples are collected correctly, test results can indicate whether the sample is zero, low, medium or high risk, and grazing management can be adjusted.” Dr Erickson said it was important to monitor livestock closely as affected animals could recover if removed off the toxic pasture early. She said the veterinary investigations may qualify for a rebate through the State Government’s Significant Disease Investigation, which aims to boost WA’s capacity for early detection by subsidising the cost of investigating diseases with specific signs.