Annual ryegrass toxicity Review of Current Management Options and Research Needs

Summary

Annual ryegrass toxicity (ARGT), resulting from the consumption of corynetoxins (CTs) produced by bacteria in the seedheads of annual ryegrass, is a significant cause of death in livestock in Western Australia and South Australia with more than 12 million sheep and cattle at risk. Since outbreaks were first documented in Australia in 1968, it has been estimated that more than 500,000 sheep and cattle have died. Non-lethal effects on production and reproduction have been poorly described but may exceed in value the losses attributed to mortality. A related syndrome, flood plain staggers which occurs sporadically in NSW and SA, contributes further deaths. While ARGT is usually manifested as a disease of Australian livestock, toxic annual ryegrass containing CTs can contaminate grain and hay, potentially rendering these products unsuitable for export and consumption. A variety of regulations and quality assurance programs continue to be implemented to safeguard animal and public health.

An intensive review of current knowledge related to the management of ARGT has been undertaken by consultation and discussion with key stakeholders and research organisations supplemented with critical appraisal of published literature and unpublished reports.

Sustained ARGT research into the biology, pathology, toxicology, chemistry, epidemiology, treatment and control of pastures and livestock has resulted in a wealth of available information and improved understanding of the syndrome. From 1969 until the current time there appears to have been continuous funding support by MLA, AWI (in their various forms) and other organisations of this broadspectrum research program. While a number of critical areas of knowledge remain to be investigated it is clear that optimal application of the existing ARGT solutions to the field and adoption by affected farmers has not yet been successful. It is believed that a significant and positive impact on the current status of ARGT can be achieved by enhancing the use of available information and tools. Furthermore, selective investment and investigation of additional areas with potential to make long lasting contributions to ARGT control are worthy of consideration.

Recommendations are presented that permit minimisation of the impact of ARGT on all affected parties, without compromise of animal productivity and welfare. Recommendations fall into four categories comprising COORDINATION AND MANAGEMENT, ENHANCING ADOPTION, FURTHER RESEARCH, and FOOD SAFETY.