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South Australia worms, flies and lice update - December 2019

SA WormBoss Worm Control Programs

SA WormBoss Drench Decision Guides





WormTest with the Best

The following are successful participants in the 2019 ParaBoss WEC QA and have demonstrated proficiency in worm egg counting.

Adelaide: Colin Trengove, Sheep Health Lecturer (UA Roseworthy campus) (

It's hard to believe we’re heading for the third hottest year globally when temperatures here for much of the time have been more like winter, rather than summer, but that is also indicative of the weather variability we experience these days…..and 2019 is not entirely done yet. (Although a later sting in the tail occurred in December!) We’ve certainly had a very dry year across most of the State except for the higher rainfall areas. This has meant some districts have failed to get much, if any, harvest.

The tough year has restricted sheep numbers, as well as parasite burdens, as we head for the smallest national flock in 100 years. The dry year combined with limited runoff, has meant that lack of stock water is also restricting flock size in some areas. A positive from the lack of moisture has been the reduced flystrike risk, but one can never be complacent about this parasite.

Recent worm monitoring has indicated that few mobs have needed drenching, except for the occasional lamb mob from the higher (>500 mm) rainfall areas. This is about as predictable as worm egg counts get, but as always, the history of the mob in question is the main predictor of the likelihood of a significant worm burden.

As a consequence, few drench resistance trials have been completed in the past few months. However, it is pleasing to see the increasing numbers of producers who perform post-drenching worm egg count DrenchChecks to see whether the drenches used have been effective.

One aspect of research this year at Roseworthy is a greater appreciation of the relatively high prevalence of both large, and to a lesser extent, the small lungworm in the 450 mm and higher rainfall regions across the State. These worms mostly go unnoticed unless a post mortem is done or a check for lungworm is requested (using the Baermann technique) when doing worm egg count monitoring. The impact of lungworm on production is also poorly understood, and current research initiatives are underway to quantify this.

All the best for the festive season and let’s hope 2020 is a more prosperous year for livestock and their owners!

For December 2019 state outlooks, please follow the links below:
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