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Victoria worms, flies and lice update - August 2015

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides

Hamilton: Andrew Whale, Livestock Logic (

Livestock Logic Key Recommendations

  • Egg counts are still rising in the south west of Victoria
  • These can go unnoticed as feed levels are good so sheep health appears well but live weight gains are compromised with worm burdens.
  • Test any weaner not tested for 3 weeks and any mature animal not tested in last 5 weeks.
  • Reduce summer supplementary feed bill through sound worm management this spring.

I write this with a lot of hope that I end up with egg on my face, but sadly we are looking at the real possibility of another dry spring. August rainfall for Hamilton has been just over 30 mm, with no more than 5 mm on any day. The 7 day outlook is dry for the remainder of August. Obviously, we have all heard plenty of talk about an El Nino event this spring/summer.

From a sheep health and nutrition perspective we need to ensure in all years (but even more so in short finish years) that sheep maximise weight gains on spring feed to reduce the amount of supplementary feeding that is required over the summer. Sheep can have non-fatal and non-clinical worm burdens that limit growth rates by 100 grams a day, these can easily go undetected for the spring and reduce sheep bodyweight by more than 5 kg. If we are grain feeding to maintain condition this could easily equate to $6 worth of grain per head. Take steps now to reduce your summer supplementary feed bill.

The below chart shows how worm egg counts in the south west of Victoria have risen sharply in July and risen further in August. We would expect the number of animals needing drenching in September to continue to rise. 

Graph 1: Percentage of weaners and mature ewes requiring drenching from Livestock Logic Laboratory this calendar year to date. Ensure worms aren’t affecting your livestock weight gains this spring and get an egg count done promptly in animals whose worm status is unknown.

Benalla: Tricia Veale (

In this area of north eastern Victoria we have had good rains. There was 121 mm total in June and July and 22 mm so far for August.

Worm egg counts are moderate generally. It’s important to get these tested regularly as it is essential to keep up with the worm levels in stock, especially in paddocks where ewes have young lambs.

A local property owner has also confirmed that he has sold rams with negative worm egg counts. That way any drench resistant worms are not passed on to new owners.

Editor's note: Presumably this means the rams had been drenched and had a zero egg count. However, unless they receive an effective drench (ideally a quarantine drenching with 4 unrelated actives) within a few hours of being transported, a sheep with a zero egg count can still be carrying worms (that it has acquired since the drench) that are not yet mature enough to be laying eggs. Don't confuse this with negative WEC ASBVs (worm egg count Australian Sheep Breeding Values), where rams are bred for worm resistance. The more negative their WEC ASBV is, the more resistant they are to worms—but they can still carry worms, including drench resistant worms. As for all introduced sheep, they should be quarantine drenched and where possible, kept in the shed/yards for a few days after (with food and water), to empty out any residual worm eggs in the dung.

It's also vital not to drench animals unless it is needed to avoid increasing drench resistance.

A large number of properties where Liver Fluke, Fasciola hepatica, have been cycling have had positive test results. Fluke now appear to be active.

Coccidian oocysts of mixed Eimeria spp. are now very evident in young calves, cria, kids and lambs.  If your young animals are scouring badly, suggest that you get some dung samples examined. You can then determine if large numbers of coccidia or worm eggs are present.

This way you can be sure of giving animals the correct treatment.

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