Maxine Lyndal-Murphy, WormBuster Lab, Brisbane, (firstname.lastname@example.org)
38% of submissions to the lab over the last 10 weeks have been in the high range of 1,000 epg or above, despite the dry conditions experienced across the region. So then, why are these counts so high? Partly it’s because of carryover in sheep from the autumn and partly carryover on pasture. In some regions, long dry grass has been protecting a shorter green understory. Conditions such as temperature and high humidity that are suitable for grass growth are also suitable for worm egg hatching and larval migration out of the dung pellet onto pasture.
There is also the distinct possibility that drenches are only removing about 90% of the worm burden. Sheep are usually drenched at about 500–800 epg, depending on the class of sheep, so there's a lot of drenching happening.
Ewes close to lambing or lactating are usually drenched at about 300 epg even if they look great! It's the future wellbeing of this valuable class of animal that is being protected by drenching at this low egg count. It is also to avoid having to drench sheep during the early lactation period and run the risk of mis-mothering.
It's time to put in place a worm management strategy for the Christmas period—if rain falls in the next few weeks sheep may need to be wormed with a product that will work at 98%. Review the Drench Decision Guide for the Summer rainfall/slopes and plains region.
Closed from Friday afternoon 21 December 2012.
Open on Monday 7 January 2013.
Larval cultures will not be set-up in the week commencing Monday 17, December 2012. Samples will still be tested for worm egg counts.