The cost of roundworms

Roundworms cost the sheep and wool industry in excess of $430 million dollars per year (Lane et al. 2015); up from the $350 million dollars estimated by Sackett et al (2006). The impact of roundworms represents the highest animal health cost to the Australian sheep industry.

The annual cost of roundworms is about $6.00/head being lowest in the sheep/cereal zone and highest in the summer high rainfall zone (where barber’s pole worm predominates). About 80% of the annual cost is associated with lost production and the remaining 20% with the costs of control.

Adoption of the WormBoss worm control program (Qld/NSW summer rainfall/ tablelands and slopes) reduced the annual cost of worms to a self-replacing Merino enterprise from $11.09/ewe, under typical regional management, to $5.80/ewe (Kelly, 2011). One reason for an increase in the cost of roundworms is the worsening situation with drench resistance.

A good example in Australia of the cost of developing drench resistance was provided in Western Australia, where scour worms predominate. Over a period of one year, Merino sheep were treated with drenches that were either 65%, 85% or 100% effective at removing roundworm infection. The annual production loss in wool and sheep (in comparison to the 100% effective treatment) amounted to (in 1996 dollars) $6.60 for the 65% effective drench and $2.45 for the 85% effective drench (Besier et al, 1996).


Kelly, GA. (2011) Investigating the effect of gastrointestinal nematodiasis in Merino sheep on the Northern Tablelands of New South Wales and implications for Integrated Parasite Management. PhD Thesis, University of New England, Armidale, NSW, Australia.

Sackett D., Holmes P., Abbott K., Jephcott S., Barber M. (2006) Assessing the economic cost of endemic disease on the profitability of Australian beef cattle and sheep producers, Meat and Livestock Australia, Sydney. pp. 119.

Watch the video extract from the ParaBoss Conference 2018 on The costs of scouring, presented by Dr John Webb Ware.

The cost of roundworms

There are about 4 million rangeland goats, 250,000 farmed meat goats and 150,000 farmed fibre goats (99% mohair) in Australia with the farmed goats split 10%, 20% and 70% into the high rainfall, sheep-wheat and pastoral zones respectively. There are also about 25,000 dairy goats and many more small herds with less than 10 animals each.

A recent survey (Woodgate et al. 2015) reported that nearly 75% of goat producers reported that worms had caused production loss in the last few years.

Roundworms cost the goat industry $2.5 million per year (Lane et al. 2015) and this represents the highest animal heath cost to the Australian goat industry. Most of these costs occur with farmed goats in the medium and high rainfall zones, rather than in the rangelands. About 70% of the annual cost is associated with lost production and the remaining 30% with the costs of control.


Lane, J., Jubb, T., Shephard, R., Webb-Ware, J., & Fordyce, G. (2015). Priority list of endemic diseases for the red meat industries (B.AHE.0010 GHD). Final report prepared for Meat & Livestock Australia.

Woodgate, R., Cornell, A. and Brunt, L. (2015). Review of parasite control recommendations for goats (B.GOA.0115). Final report prepared for Meat & Livestock Australia.

Watch the video extract from the ParaBoss Conference 2018 on Scouring: causes, diagnosis, management and treatment, presented by Dr John Webb Ware and Dr Caroline Jacobson.