Charles Sturt University (CSU) research has identified a treatment that could treat ryegrass staggers, which costs Australian livestock producers more than $100 million each year.
Perennial ryegrass toxicoses (PRGT), or ryegrass staggers, is an ongoing and costly problem for Australian producers in the form of lost production and increased livestock mortality.
CSU Senior Lecturer in veterinary physiology Dr Jane Quinn said the condition was caused by a toxin produced by a naturally occurring fungus in the some varieties of perennial ryegrass.
"The affected livestock can develop the staggers which makes them very difficult to manage and can cause death," she said.
"Even when people aren't necessarily seeing the animals shaking or falling over there may be significant production losses with reduced fertility, ill-thrift and reduced milk production in dairy cattle."
Most research has focused on developing new strains of ryegrass to make them less toxic than the original varieties, or on binding agents to prevent animals absorbing the toxins. Neither approach has been reliable or totally effective.
The new research of Dr Quinn, Dr Scott Edwards and PhD student Dr Martin Combs from CSU's School of Animal and Veterinary Sciences, has focused on the central nervous system, the primary target of the ryegrass toxin.
Dr Combs said the research has identified a chemical compound that appears effective at reducing clinical signs of ryegrass staggers in affected sheep, by treating the nervous system directly.
"In our pen trials we found that sheep showing severe signs of the staggers, who would consistently fall down when asked to move, could move more normally and without falling when treated with this compound," said Dr Combs.
"When we tested their muscle activity they also showed reduced tremor. You could potentially treat a whole mob of sheep using this approach which is a key outcome for producers with affected animals."
Dr Quinn said one of the main problems for producers is that affected animals are very difficult to move, either for routine management or to get them off the pastures that are doing them harm.
"If we can improve the animal's movement, so they can be moved without falling, then we should be able to reduce the numbers that die during these outbreaks and also allow producers to manage their animals more effectively," she said.
Outbreaks of ryegrass staggers occur during summer and autumn, particularly in southern Victoria, Tasmania and in New Zealand.
The researchers and MLA have patented their work and are seeking interest from commercial partners to develop a flock-wide therapeutic treatment program.