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Tasmania worm update - August 2013

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

If you fly into Launceston you see nothing but water.  Not from flooding (although the Meander and North Esk have flooded and the mighty South Esk is nicely full), but just from a very wet August and early August.  Water is lying everywhere as our poorly drained duplex clay soils struggle to cope with heaven's bounty.  With the prodigious wet comes black scour worm (Trich. vitrinus).    When you can see more puddles than grass, with the thermometer struggling to get to double figures, be on the lookout for the characteristic tarry scour.  Black scour is a highly pathogenic worm:  it is quite capable of killing all classes of sheep, but it can cause havoc in young stock and late pregnant ewes.  Combine the two vulnerable classes in the form of late pregnant ewe lambs and you may have trouble.

While conditions are good for the Trichs, it should not be the disaster we saw in (from memory) in 2002.  That year the wet summer laid down additional contamination followed by drought conditions so that sheep entered the winter in light condition.  When the big wet came sheep died in spades.  This year we have had low worm burdens with the stock generally healthy.  Most mobs are lambing down on the requisite pasture levels.  The rain has curtailed some supplementary feeding, and mobs have been removed from winter cereals and new pastures, but generally nutrition is satisfactory.  Nevertheless, be wary, and if you see signs, investigate.