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South Australia worms, flies and lice update - December 2015

SA WormBoss Worm Control Programs

SA WormBoss Drench Decision Guides


Adelaide: Colin Trengove, Sheep Health Lecturer (UA Roseworthy campus) (trengovet@icloud.com)

The heat and lack of moisture continues almost unrelenting since September. El Niño has certainly struck with a vengeance and was unimaginable only three months ago. How quickly weather patterns can change and worms must also be feeling the heat.

Recent monitoring indicates minor worm burdens only sufficient to keep the immune system stimulated. However, this is no time for complacency as weaners and hoggets can still be caught with significant carryover burdens from winter/spring. There is no substitute for regular monitoring as worms often "throw a curve ball"! Nonetheless, those who have been monitoring may have saved on drench this summer as sheep have been in surprisingly good condition and there is little value in drenching sheep in 3+ condition with low worm counts i.e. <<100 eggs per gram (epg).

That said, I know one advisor who managed to do 15 drench trials this spring which is commendable in anyone's books. It is quite an achievement to do that many drench trials in any year and especially a dry one. It is a worthy strategy, but few go to the effort of following it through. We all know that drench resistance is common place, but how many stockowners have a good understanding of what anthelmintics work in their flock? Recent reports of emerging resistance to Zolvix® highlights the need to maintain vigilance against worms and have strategies in place to prolong drench efficacy. Minimizing the use of all chemicals is the first step and especially repeated use. There are no shortcuts to monitoring worm challenge and what chemicals are effective in dealing with this challenge.

Recent cases of scours in young sheep in the mid north, unrelated to worms, and severe Footrot in the Adelaide hills highlight that challenges to animal health are never far away irrespective of recent weather patterns—certainly not what you'd expect given the dry conditions. However, whether the challenge is bacterial or parasitic, costs can escalate quickly and so frequent monitoring with your five (or six) senses as well as faecal sampling can never be over utilized! And of course your friendly animal health expert is never too far away if you need assistance.

May your Christmas be merry and the New Year bring new joy!