Annual ryegrass toxicity and blown grass / beard grass poisoning

This Primefact covers annual ryegrass toxicity (ARGT) and the related livestock poisonings associated with blown grass (Agrostis avenacea) and annual beard grass (Polypogon monspiliensis) in NSW Australia.

For at least 40 years an unusual form of poisoning has occurred in livestock grazing annual ryegrass and annual beard grass pastures in South Australia and Western Australia. In 1990 this same form of poisoning occurred in NSW in livestock grazing another annual grass called blown grass. Frequently referred to as 'ARGT' or 'ARGT-like', this toxicity kills large numbers of livestock throughout southern Australia every year. It can rise to outbreak proportions in some districts in years with particularly favourable weather conditions. Topics covered include the following:

• How do some annual grasses become toxic?
• Grasses affected by the bacterium
• Signs in affected livestock
• Delayed onset of clinical signs
• Autopsy and laboratory findings
• What to look for in suspect pastures.