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Tasmania worms, flies and lice update - March 2016

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

Since the last posting the weather has been fickle, to say the least.  After the big rain of January we’ve had two follow-ups of about 25mm each here in the north, and more or less in other parts.  So, at the very least there is green dust, but the season is on a knife’s edge as there have been plenty of days with hot drying winds.  Our water storages continue to decline so I ask all mainland readers (are there any?) to drop a few megawatts of power into an envelope and post it to our power authority.

For the most part the worms have remained quiet.  Egg counts have been satisfactorily low, and it looks like we should have reasonable worm control into the winter. 

There have been a few exceptions.  Properties finishing lambs on grass under pivots have been hit by their post-Christmas dose of trichs.  In nearly all cases these paddocks were grazed by lambing ewes in the spring.  Without cattle or dry sheep to “spell” them, contamination deposited in mid spring is recycled to dangerous levels post-weaning.  Paddocks harvested for grass seed have enough of a spell to remain safe, even if they have been grazed by lambing ewes earlier.

Some properties in the Fingal Valley had break-downs in weaners on paddocks that before the January rain, were as bare as Kojak’s head (readers under 50 should follow this link).  I’m not sure what happened here: maybe a less than effective weaning drench, and severe nutritional stress meant that a modest worm burden delivered clinical parasitism.

Finally, it’s time for an annual warning:  all that squitters is not worms, but it probably is.  Twice in the last month I’ve been asked for antibiotics to combat coccidiosis.  Can’t possibly be worms, I drenched them a few weeks ago.  Well, a few weeks turned out to be 4 weeks and WECs were north of 800 epg.  In both cases the weaning/first summer drench was less than 100%.  In 25 years in Tas I’ve yet to see a genuine case of coccidiosis in sheep.  We see Yersinia, but mostly in winter.

In contrast, there have been two cases of non-wormy squitters.  We knew this from the time the phone rang because owners had gone to the trouble of getting WECs.  Please get a diagnosis before treating.