Queensland worms, flies and lice update - March 2020

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

Many areas of Queensland received good rain in the last month and while the rain has been good for grass and sheep, it has been even better for worm larvae. If you have had rain, it is essential to check for worms in your sheep. The life cycle takes 3 weeks from eggs on pasture to adult worms in the gut of the host. Producers are encouraged to WormTest every 4–6 weeks and look for visible signs of worm infestation in representative mobs every week, better still, twice a week.  http://www.wormboss.com.au/sheep-goats/worms/roundworms/signs-of-worms.php

In the absence of worm challenge due to the prolonged dry weather, immunity of sheep to barber’s pole tends to drop, and, exacerbated by ongoing poor nutrition, leaves sheep more susceptible than usual to the effects of the worm infestation.

When grass is short (<10–15cm) worm larvae become concentrated over the smaller amount of available leaf area increasing the chances of being eaten during grazing. If drenching is required, it’s best to use a ‘combination’ drench particularly if you do not have any useful test data about the resistance levels in worms on your property. WormTest the mob a few days before drenching and again, 10–14 days after drenching, with a zero worm egg count result being ideal. A confronting read about the level of drench resistance in barber’s pole in Queensland can be found on   http://www.wormboss.com.au/sheep-goats/tests-tools/management-tools/drench-resistance/resistance-status-of-drench-groups.php

If you are in the process of restocking, plan to avoid introducing drench resistance worms by strictly adhering to all the quarantine protocols appropriate to your property.  

After rain, check sheep for flystrike every 1–2 days untill the sheep dry out and humidity drops, as temperatures day and night are remaining quite warm. Any treatment applied needs to be supported by preventative management such as crutching and shearing for sustained prevention of strikes.

Be aware that hordes of nuisance flies can cause distress to rams in particular, and the mosquitoes and biting midges considered the vectors of three-day sickness in cattle are prolific at this time.