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Victoria worms, flies and lice update - November 2016

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides


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

Livestock Logic Key Recommendations

  • When egg counts allow, delay 1st Summer Drench until faeces are firm
  • Monitoring and making informed 1st summer drench decisions cannot be done without Worm Egg Counts

Have you done your summer worm egg count monitoring?

Livestock Logic results show that for those producers who will blanket summer drench their sheep this summer, will potentially waste a lot of chemical, time and $$ as well as put increased selection pressure on drench chemicals. Worm egg counts over summer allow us to get our summer drench timing correct. High egg counts need action immediately, low egg count mobs do not need drenching as they will not have any production loss and will not be causing significant contamination of pastures over summer, moderate egg counts need a drench but the timing is critical. Drench too early and you increase the need for a 2nd summer drench, as there will be larval pickup post drenching. Drench too late and you allow for significant worm eggs to survive the summer in pelleted faeces.

For this reason observing the shape of your sheep’s faeces is the key to timing the summer drench appropriately. Once they firm up its 1st summer drench time!!!


Graph 1: Percentage of Sheep Requiring Drenching from Livestock Logic Laboratory over the last 5 months.

This shows that young sheep have much lower immunity to worms than older sheep. Most 2015 drop animals are only 15–16 months old, some of these have recently lambed (maternal ewe lambs) making them more susceptible to worms. It pays to be most vigilant in all younger sheep as they are the most likely to lose production as a result of worms and they are also the least able to handle production loss heading into summer as pasture quality rapidly deteriorates.

Temperatures have started to warm up in the south west, and also dry up the much anticipated potential flystrike. Strike risk is now looking much less of a threat, showing that high rainfall prior to the onset of warm weather has little impact on increasing the flystrike risk. The early December period, if conditions stay warm, will be telling us whether or not the 2016/17 summer will be a high flystrike risk period.