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Queensland worms, flies and lice update - November 2017

Brisbane: Maxine Murphy, Veterinary Parasitologist (maxine@paraboss.com.au)

Worm Alert!

It’s summer, it’s warm and there have been storms and overcast weather for a number of weeks.

This is the time of the year when barber’s pole infections develop explosively and kill sheep, especially lambs and weaners, and often suddenly. These weather conditions have ensured that almost every worm egg dropped onto pasture by wormy sheep in the last few weeks has hatched and now paddocks are swamped with infective larvae. And the conditions are just as favourable for flies.

Wet, Wet, Wet! Check out the Monthly rainfall totals map for Queensland

Check stock!

Stock, especially young stock, need to be checked weekly until the end of summer. Look for signs of infections such as pale mucous membranes around the eyes (use the FAMACHA© colour cards) and gums, lethargy, reluctance to move if approached, or sudden deaths.  Stock congregated on higher ground and unable to move about in the wet conditions, or crowded by long grass often experience a fast build-up of worms as conditions under foot become highly contaminated.

As well as sheep, goats can also succumb rapidly to worm infestations and should also be closely monitored at this time of the year. Check a number of mobs, for example, one mob in every three (if stock are of the same class, pastured under similar paddock conditions, and with similar drenching histories) to gauge worminess across the flock.

Drench stock!

Any anaemic or lethargic stock should be drenched where they are in the paddock and not put in the ute to be taken home. If stock are marooned on areas of higher land, a long acting drench that continues to work in some cases for up to 100 days, may be warranted to give sustained protection until paddocks dry and stock can be moved.

Drench alert!

There is considerable resistance in barber’s pole to many drench groups so don’t count on any product giving a good kill until you have tested it, post drench. This is peak worm season and it is necessary that any drench used at this time of the year is very effective,  and produces at least 98% kill of the worm burden. Short acting combination drenches such as Startect®, Zolvix® Plus and triple combinations that include a naphthalophos, should be investigated.

A quick way to get an idea of the percentage of worms killed by the drench is to use the “DrenchCheck”, where dung samples for worm counts are taken when a mob is drenched, and then again 14 days later. Comparing the worm egg count and larval culture results before and after drenching gives a reasonable indicator of drench efficiency.  

Fly alert!

Producers should now be checking regularly for flystrike wounds with their telltale smell and dark, damp wool caused by the maggots. Recently marked lambs are at high risk if a preventative treatment was not applied thoroughly at marking. Preventative measures can be put in place now in advance of the expected fly wave.