< Back to Outlooks Listing

Queensland worms, flies and lice update - April 2020

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

Summer has been a long, drawn-out and tedious affair. Daytime temperatures are still reaching over 30°C in many regions. Until average temperatures drop to below 18°C for a few weeks, barber’s pole will stay a threat—especially if it rains. Currently, the cooler night temperatures are only slowing the speed of egg hatch, not stopping it. As a general rule of thumb, temperatures in Queensland remain warm enough throughout the year to support the barber’s pole cycle. Sufficient moisture is the limiting factor for worm development.

If any rain falls, WormTests conducted on representative mobs 4 weeks later will be the order of the day. A single WormTest result is just a snapshot in time and not the whole picture; it cannot indicate if worms are building, falling or remaining stable. Only a follow-up WormTest 4–6 weeks after the first can warn if a drench is needed. For many mobs, this drench, preferably a short-acting drench, could well coincide with the pre-lamb drench.

Now is the time to start locking up paddocks ear-marked for lambing. Removing sheep for a few months will stop further egg drop onto paddocks, allow paddocks time to recover from grazing and give time for infective larvae to die.

Preparing low-worm risk paddocks for lambing during July to October will take about 4–5 months. On the tablelands, spell paddocks by removing sheep or graze with adult cattle. Adult sheep could continue to be grazed for up to 21 days after an effective drench. This time is in addition to the length of the protection period of the long-acting drench. Short-acting drenches do not offer any prolonged protection against reinfection meaning that sheep can only be grazed for up to 21 days after this type of drench. On the slopes and plains where the weather is drier, preparation time for low-worm risk paddocks is about 3–4 months at this time of the year. Again, spell paddocks, graze with cattle or use them for cropping.

Monitoring for fly burdens should continue, although temperatures are falling, reducing the fly threat.