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Victoria worms, flies and lice update - February 2016

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides

Hamilton: Andrew Whale, Livestock Logic (

Livestock Logic Key Recommendations

Across the region, egg counts are quite variable and reflect the timing of the last drench.

If animals did not receive a 1st summer drench then a worm egg count is due ASAP.

Weaners should also be worm tested in early March as a priority to monitor any build-up after the summer rain in late January.

Most areas in the immediate vicinity of Hamilton received a decent rain event in late January (4 weeks ago), although it feels like the first time since winter.

What does this mean for worm egg counts?

The timing of worm egg counts following summer rain is pivotal to maximise the information generated by testing. We would advise you test weaner lamb mobs in early March as a priority, i.e. 4 weeks after the late-January rain event, as this gives sufficient time for eggs to hatch from faeces and larvae to be ingested, and then complete the lifecycle by maturing within the animal and excreting eggs.

Mature sheep not tested since mid-December should also be re-checked now. If worm egg count levels are high then pasture contamination levels need to be reduced before autumn, in order to reduce winter worm burdens.

We have said it before: If you have high worm burden issues in winter, then over the late summer-early autumn period you need to monitor your stock more frequently.

We are seeing a massive spread in the range of worm egg counts that is largely dependent on the timing of the mob’s last drench. As a rule, animals drenched pre-December now have egg counts high enough to warrant a drench aimed at reducing pasture contamination levels. As we move into cooler autumn conditions, worm larvae survive on pastures, and this strategic drench will help to limit the number of worm eggs available that could hatch to larvae. Mobs that received a genuine summer drench (post-December) mostly have low WEC levels and are not in need of a second summer drench, but they should be monitored 8 weeks post-drench to ensure they are not contaminating pastures.

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