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Victoria worms, flies and lice update - September 2015

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides


Hamilton: Andrew Whale, Livestock Logic (a.whale@livestocklogic.com.au)

Livestock Logic Key Recommendations

  • Egg counts have been fairly constant—they will be causing production loss in properties that haven’t drenched or are not monitoring regularly.
  • Give priority to 2015 drop lambs that are already weaned, then 2014 drop hoggets.
  • Are you due for a drench resistance test? If none have been done in the last 2–3 years, call your independent animal health advisor to arrange one.

The last month has been pleasing in the south west. A month ago I was quite pessimistic about the season, but most areas have had just enough rain to keep grass growing and the weather has been mild. There is still very little soil moisture so rainfall every week is required to keep pastures growing from here on in. Luckily the regular 5 mm rain events are doing enough at the present.

While worms will always cause production loss on all farms every year in this climate, the winter has not seen the cases of mortality from worm damage that we would typically see in the south west. One of the few benefits of a failed spring last year is that worm populations heading into winter were well below other years.

Our spring worm egg counts are also lower compared to other years, this is seeing less ewes needing drenching at lamb marking or weaning than previous years. But there have still been plenty of properties with high egg counts that would reduce weight gains if stock are not drenched so we cannot afford to be complacent with our worm management.

Livestock Logic has been busy with drench resistance testing over the last month with autumn drop lambs at weaning and we would encourage all producers to consider the need to do a drench resistance test prior to drenching lambs at weaning. Discuss with your animal health advisor the merits of analysing the performance of drenches available to create a drench plan for your sheep.

Ensuring your summer drench selection is highly effective is the first step to ensuring you keep on top of worms next winter.


Figure 1: Percentage of Weaners and Mature Ewes Requiring Drenching from Livestock Logic Laboratory this calendar year to date. This shows that worm levels have been fairly constant for the past 3 months.