Queensland worms, flies and lice update - September 2019

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

Sixty-five per cent of Queensland is drought declared, mostly in the area extending south of a line from Townsville on the coast, west to the Northern Territory border and south to the New South Wales border. Bushfires have added another level of strain for many producers.

Finding enough feed and water to support lambing/kidding and lactation will be paramount this spring.

In the south-east around Brisbane, where rain has been patchy, plans to develop low worm paddocks for young stock (lambs/kids) should be well in place. A couple of days of up to 10 mm rain is forecast for later in the week, and as temperatures are well into the zone for egg hatching, barber’s pole will be active. The drier conditions should put a brake on the characteristic rapid development we usually see at this time of the year. Importantly, each property is different, so do worm egg counts 3 weeks after rain or if stock are crowded.

In the northern coastal regions that have received adequate rain, fast paddock rotations to control barber’s pole should be considered coming into summer if rain continues. The idea behind the fast rotations is that once barber’s pole eggs have hatched, development proceeds to the infective larval stage. Under current conditions, infective larvae can be on grass in 4–10 days. Ideally, stock are rotated through paddocks twice a week, but more usually rotations are between 1 to 3 weeks. Scour worms are better equipped to cope with drier conditions than barber’s pole and numbers could also build-up if under irrigation.

Determining drench effectiveness can be tricky in the absence of drench resistance testing. However, if you do worm egg counts, check stock at drenching. This involves taking dung samples for a worm test and culture at drenching then again 10–14 days later. The comparison of ‘before’ and ‘after’ worm egg counts will indicate how well the drenched worked. Ideally, the worm egg count at day 10–14 should be zero. Less than 100 eggs per gram is acceptable but realise that some resistant worms are present.