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Economic Assessment of the Endophyte-Infected Perennial Ryegrass on Australian Livestock Producers

Approximately 26.5M sheep (25% of the national flock) are at risk of PRGT, the majority of which run in the temperate south eastern part of Australia, with a small proportion in south west WA. Of these 26.5 million, 12.4 million are considered to have a high risk of PRGT, 1.6 million have a moderate risk and 12.5 million have a low risk.  Approximately 1.5M beef cattle (6% of the national herd) are at risk of PRGT.  

The national cost of PRGT was estimated using flock and herd models in which a range of production parameters such as fleece weight, sale weights, and death rates can be varied and the economic estimates determined. Production losses were determined by a combination of literature review and expert opinion.  

The annual average cost of PRGT to the Australian sheep industry is estimated to be $63.6M. A severe outbreak is estimated to cost $12.15 per head in a merino flock and $20.86 per head in a prime lamb flock. Of the total cost, $33.6M is due to a decrease in income associated with deaths (and hence fewer sale sheep), reduced flock fertility and reduced wool quality. The balance of the cost relates to an increase in expenditure associated predominantly with additional labour and supplementary feed. 

The annual average cost of PRGT to the Australian beef cattle industry is estimated to be $1.5M. The cost of an outbreak is estimated to be $4.98 per head, giving an annual average cost of $1.00 per head. The cost is substantially lower than for sheep because cattle appear to be less severely affected in PRGT outbreaks. 

A number of strategies for the prevention of PRGT were investigated. In high and moderate risk areas the replacement of wild endophyte infected PRG with alternative perennial grasses (which include beneficial endophyte infected PRG) offers an economically and technically viable option to manage PRGT. Novel endophyte PRG may also provide a viable alternative perennial pasture providing it persists in the pasture sward and is not invaded by wild-type PRG. 

The animal welfare issues associated with PRGT are a major concern for both the sheep and cattle industry. The welfare issues alone justify the development of better management strategies for PRGT outbreaks. Research priorities for PRGT include investigation of production losses, particularly clinical and sub clinical losses, persistence of novel endophyte PRG, PRG seed survival in the digestive tract of livestock and development of predictive models. Extension of the benefits of other perennial grasses for PRGT control is required to encourage adoption of alternative perennial grasses, including beneficial endophyte varieties of PRG.


Title Size Date published
1.3MB 16/07/2007


Contract No. Title Start date End date Funding type
Economic Assessment of the Endophyte-Infected Perennial Ryegrass on Australian Livestock Producers
02/05/2005 23/02/2007

This page was last updated on 06/07/2018

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