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Tasmania worms, flies and lice update - June 2017

Tasmania WormBoss Worm Control Programs

Tasmania WormBoss Drench Decision Guides





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

The last month has been quite dry, but most areas have at least some green pick. There were some frosts in late May and into June, but not as many or as severe as the dry weather may have predicated. Nevertheless, everybody is looking for rain to get some sheep feed before heavier frosts really slow things.

The worms are like a Territory forecast: exactly the same as at the last report. Ewes good, merino weaners (all of a sudden, flavour of the month) approaching trigger levels; finishing lambs may also need a drench, particularly if on irrigated perennial pastures or 2nd year short-rotation rye grass. So, with the worm report out of the way let’s move onto some para-parasite topics.

Firstly, I encourage clients to have a finishing date for lambs. This is primarily nutritional advice (i.e. if the lambs are gone you will not compromise nutritional planning for the ewes, rather than worrying about trying to get a late winter price spike while lambs grow at less than 100g/day on depleted pastures). A side-benefit is that having no lambs left is that you may give the finishing paddocks enough of a break (grazing with low worm-status ewes, cattle or spelling) to substantially reduce the parasite burden (compared with sending the last lamb on August 1, and stocking with lambing ewes on August 21).

Secondly, we have seen 3 large Yersinia outbreaks. In all cases the owners had enough worm information (i.e. tight monitoring with worm egg counting WECs) that they did not rush to drench. Post Mortems and speculative treatment of a few animals with antibiotics provided an answer and a treatment. Now, Yersinia is a stress associated disease, and the most common stressors are (observationally) worms followed by wet, cold weather. The next most common stressor is NBI (No Bloody Idea), and these were all examples of NBI. The point of this homily is that if you monitor you will not waste time and drench sheep with Yersinia predisposed by NBI. And please don’t let another person tell me they drenched because they could smell the worms!

Finally, there are rumours of injectable cattle drench use in sheep. While financially expedient, this is not on. Apart from not knowing the ESI (and don’t tell me it is only being used in retained stock – it is easy to sell a few ugly ewes), there is also the issue of recording in QA schemes.