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Tasmania worms, flies and lice update - December 2017

Tasmania WormBoss Worm Control Programs

Tasmania WormBoss Drench Decision Guides





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

Season’s greetings from the deep south where the people are strong and the worms still susceptible.

The season has been very dry, although the rain that was supposed to devastate Victoria also dumped a deal here, particularly on the droughted east coast, and in Bothwell and Derwent Valley.

Weaning is well underway and most people should complete it by Christmas.  If not, why not?  Few things are so disheartening as seeing ewes and lambs grazing a reasonable paddock, when it should be used only by the lambs without competition from their mothers. This would be parasitically and nutritionally sensible. 

Because the spring has been so dry and warm, the spring and early summer environmental decontamination should have been reasonably good. This will improve the strategic benefit of the weaning/first summer drench. Monitor ewes and “parked” lambs on perennial pastures, and give a second summer drench at a trigger of 100–150 eggs per gram. This may be as early as early February (parked lambs) or as late as mid-March (ewes), depending on the amount of contamination on the paddock at the time of the first summer drench. 

Summer rain often facilitates black scour worm in lambs soon after weaning.  While a lot of the state was drenched two weeks ago, I doubt there was sufficient larval contamination on pastures to respond and cause a problem. Nevertheless, watch and monitor your weaners closely, particularly the Merinos. The first detoxifying job on Boxing Day should be to check the Merino weaners, and do an egg count if you can.

This picture shows some lambs on a client’s finishing system. I’ve included the picture for a couple of reasons: first, it’s amazing how worm-free clover circles are in comparison to graze or perennial pasture circles. There are many reasons for this but chief among them is that low winter growth makes it unlikely the paddock will be grazed by lambing ewes. In many cases the first grazing is the hay mower or the clover seed harvester. Long-spelled paddocks are clean paddocks.

Secondly, lamb finishers are lamb buyers. Some of these guys buy tens of thousands of lambs, including many from the mainland. This raises many biosecurity issues, but chief amongst them is the possibility of importing a super-resistant worm population. Therefore, ask for a National Sheep Health Statement (SHS) and enquire about the worm resistance status and drench new arrivals onto the place with a multi-active that fits with the Withholding Periods / Export slaughter Intervals (WHP/ESI) for the finishing date. Most importantly, do a 14-day post-drenching count to make sure your drench choice has worked.

Happy Christmas and New Year. If you are on the roads over the holidays make sure you are in a motorcar.