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Tasmania worms, flies and lice update - April 2017

Tasmania WormBoss Worm Control Programs

Tasmania WormBoss Drench Decision Guides





Perth: Paul Nilon, Nilon Farm Health (pandonilon@bigpond.com)

Tasmania has remained dry. There were widespread, light falls at the start of April, and again this weekend past (22nd, 23rd). These showers were enough to spark some ryegrass staggers, but little else.

Because it is dry, many producers assume all is hunky-dory. While this is generally the case with adult sheep, many lambs are running high burdens of worms. We are far enough into the autumn that previously “clean” grass circles and other fodder crops are now accumulating contamination, and exposing lambs to risk.

A client asked how a WEC (worm egg count) could go from 150 eggs per gram (epg) to over 1000 epg in the course of a few weeks. Well, easily: it’s possible the first count was skewed. Best to submit at least 20 samples and ask the laboratory to bulk those rather than the traditional 10. If you have doubts about a WEC (i.e., the sheep are doing poorly and/or scouring), do another test. Even if both counts are correct, some paddocks and mobs reach a tipping point where the sheep’s vulnerability and the paddock’s contamination allow rapid rise in burdens.

Some thoughts on barber’s pole worm: this is not a huge problem outside of the north-east coast and Flinders Island. However, there is a collection of places south of Launceston where it is now common, and larval differentiations from irrigation paddocks state-wide show the worm is starting to make a run. Grass circles seem vulnerable while clover circles are relatively robust. As mentioned last month, look for weak sheep with high egg counts (often in the thousands). As the lamb-finishing season comes to an end, consider grazing barber’s pole paddocks with cattle, if that is an option.

The heavy rain last winter means that the lower reaches of the Macquarie and South Esk Rivers may (again) be harbouring fluke. Sheep grazing the marsh paddocks (usually dry ewes) are at risk. Burdens picked up in mid to late summer (we always run behind time in Tasmania) will now be causing damage. Fluke is a differential for weak, anaemic sheep. You can test with a dung sample or by collecting bloods for a Fluke Antigen Test (an ELISA test), which is offered through Charles Sturt Veterinary Laboratory and the NSW DPI State Veterinary Diagnostic Laboratory.