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Queensland worms, flies and lice update - February 2018

Texas: Noel O’Dempsey, Sheep Veterinary Consultant (odempseyn@gmail.com)

Some musings: I was riding around this morning inspecting the sheep, sweating from the heat and thinking about worm control (what a trifecta!!!). Even with the heat and the dry weather I decided that I needed to keep a close eye on the worm burdens by regular worm egg counting (WormTests); especially the ewes and lambs I have running on cultivation country at fairly high stocking rates, so that I do not get caught out when worm numbers start to increase, and so I can move quickly when the need is identified.  However the hot weather will be killing off any barber’s pole larvae on pasture at a more rapid rate, but not nearly as fast as it has reduced my enthusiasm for fencing repairs.

I purchased three Merino rams the other day. One had a YWEC (Yearling worm egg count, Module Tool 9.3) of -40%, the other two were -34% and -20%. There were other rams in the sale with better YWEC values (more negative) but they were either dearer than I wanted to pay or I didn’t like their wool or performance in other characteristics. The progeny of these three rams will carry fewer worms than the average and I will have to drench less often as a result. I am glad my stud is offering worm-resistant rams.


Toowoomba: Dr Peter Lynch, veterinarian, Livestock Veterinary Services (peterlynch@shwds.com.au)

The hot and dry weather is continuing to have a significant effect on egg counts in Queensland. I have had zero counts from a number of clients in the far west. At the same time, I have significant worm egg counts out of sheep not far away from here after they were lucky to catch a small storm. To make matters worse, some of these flocks are showing signs of Mectin (macrocyclic lactone) resistance.

(Editor’s note: signs of drench resistance include sheep appearing to be wormy again soon after the drench. Worm eggs would still be present (not zero) on a WormTest if taken 14 days after the drench.)

If you have had rain and have not drenched or done a WormTest, you should do one now. It is quick and easy to collect faecal samples first thing in the morning from a sheep camp. Remember that the pellets must be fresh (preferably still moist) and send them by the quickest method to your local testing laboratory

It is now more important than ever to do a day 14 post-worming drench-test (DrenchCheck) to be sure that the drench you are using is effective. Simply buying the cheapest drench or drench on hand in the local store may not be the best decision.