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Queensland worms, flies and lice update - September 2015

Brisbane: Maxine Murphy, Veterinary Parasitologist (maxine@paraboss.com.au)

Eighty percent of Queensland is drought declared. For many producers, finding enough feed to support ewe lambing and lactation will be paramount. Sheep crowding onto grass around leaky watering points are at risk of barber’s pole infestations, further exacerbating less than adequate nutrition.

In the south east where rainfall has been patchy plans to create low worm paddocks for weaners should be well in place. Even if storms remain patchy barber’s pole will be in its element and the November drench for lambs and/or weaners will need to be very effective (>98% reduction of the worm egg count).

In the absence of drench resistance testing (we know the uptake of testing is very poor), determining drench effectiveness can be tricky.

If you do worm egg counts, simply check each drench when a mob is to be treated. This involves taking dung samples for a worm test when the mob is drenched, then again 10–14 days later. You will also need larval cultures. Comparison of the before and after worm egg counts will indicate how well the drenched worked. Ideally, the worm egg count at day 10–14 should be zero or at least, less than 100 epg.  

If you don’t do worm egg counts, consider the number of times you have used a particular drench over the last three years. If you have used it often then it is time to rotate to another product containing the newer actives, and most importantly, use it with other effective drench actives (talk to your vet or reseller, and read the drench labels). If a worm problem returns quickly after a particular drench, then the drench is most likely failing.

Resistance to the new chemical, Zolvix®, has recently been reported. See this month’s feature article.

If your drench options are few and you are in the higher rainfall region of the tablelands and slopes where barber’s pole infestations occur every year, take time to read about the Barbervax® vaccine.