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Black Scour Worm Alert for Tasmania

Paul Nilon - Nilon Farm Health, Tasmania

Last month we discussed the high risk of black scour worm.  And so it proved to be.  August delivered 200mm of rain to many areas in the North and there were several cases of severe parasitism due to black scour.  In two cases the sheep were drenched about 25 days previously.  PMs revealed upper small intestines that looked like they had been scrubbed with a wire brush and White King (White King for the Black Scour:  maybe I should be in advertising!).  Under the microscope mucosal scrapings looked like a spaghetti pot.  

Diligent clients escaped the issue.  Two clients intending to forego the pre-lamb drench changed their minds when egg counts in the run-up to shearing sky rocketed.  A few others opted for a long-acting drench.  Most will muddle through with a short acting drench. However, you should reassess the need for a lamb marking drench.  If the ewes are scouring and milking poorly, get some WECs done.  If the ewes need drenching, the lambs may also, particularly if lambing is protracted.   With some warm weather and rapid pasture growth the worm challenge should drop off.  However, heavily parasitised ewes may continue to milk poorly, in which case consider early weaning (12 weeks after the start of lambing).

This advice applies mostly to Merino producers in the north of the State.  Most XB flocks are looking robust.  Areas south of Campbell Town are nicely moist, but not sodden, and the worm challenge is commensurately diminished.

On a happy note one of a few "Smart Graze" clients reported his 2013 results yesterday.  For the year he has given his weaners two summer drenches, a drench onto the smart graze paddocks in late April, and nothing through the winter.  Smart graze works.  I urge subscribers to study Lewis Kahn's WB contribution on grazing management.  Even small measures can make a huge difference at critical times.