Arsenal of worm-busting tools

Smoothies anyone? WormBoss's Deb Maxwell demonstrates how to prepare a fecal sample ahead of a worm egg count.
Smoothies anyone? WormBoss's Deb Maxwell demonstrates how to prepare a fecal sample ahead of a worm egg count.

While Deepwater was referred to as the epicentre of barber’s pole infestations affecting Australian sheep graziers, those at a WormBoss workshop on Wednesday, November 1 were made aware of the arsenal of tools available to them to combat the parasite.

The workshop was held – aptly enough – at Kurrajong, Jude Cox’s property just north of the epicentre, under the guidance of WormBoss operations manager Deb Maxwell.

Ms Maxwell said while none of the measures are a ‘golden bullet’ for eradicating the production-sucking parasite, judicious management of paddock preparation, worm fecal egg counts and drench resistance management can keep worm burdens to a manageable level.

With barber’s pole worm larvae able to survive six months or more in cooler weather (they tend to wriggle their way to death within three months in summer months), Ms Maxwell warned that a long lead time is required to minimise worm burdens on lambing and weaning paddocks. Paying due attention to these two critical periods of the production cycle, however, can set up the farm for success through the year, she said.

“The impact it makes is huge.”

Ms Maxwell said a good start to the production cycle will keep worm egg counts (WECs) lower across the board, helping to build immunity and avoid getting into the yo-yo practice of drenching when egg counts are high to reduce them to near-zero, only to rapidly rise again to a high count and require further drenching.

The recommended practice is to start preparing the lambing paddock when the ram goes in for joining, particularly with a spring lambing, and to prepare the weaning paddock when lambing begins. Preparation means allowing exiting larvae to die and not adding to the paddock’s worm burden during that period, but this doesn’t necessarily mean locking it up.

Choosing rams with lower-than-average worm egg count estimated breeding values can improve the resiliance of a flock against barber's pole worm.

Choosing rams with lower-than-average worm egg count estimated breeding values can improve the resiliance of a flock against barber's pole worm.

The paddock can be cropped or grazed by other species, and even by sheep (and other barber’s pole-prone animal like goats and alpacas) if they’re protected by an effective drench or if weather conditions are right. Worm eggs die if they don’t hatch within five days, and hatching requires average daily temperatures above 18 degrees and 10-15 millimetres of rain over that period.

A hard graze just before the start of the preparation period will also open up the paddock to more sun exposure and heat, reducing the lifespan of existing larvae.

Ms Maxwell said the Northern Tablelands is ‘gifted’ with four months of the year in which average daily temperatures don’t reach 18 degrees, carving a large slice out of a six-month preparation. Also even ‘wormy’ sheep can graze the paddock during rain-free periods which extend at least five days past their removal, as long as there are no water-logged areas to promote egg hatching.

The effectiveness of available drenches can only be determined by drench resistance testing, Ms Maxwell said, and even then she recommended combining drenches to prolong the effectiveness of each drench group. With Deepwater’s  barbers pole worm history also contributing to its status of having more drench resistance than the rest of Australia, experts were on hand to explain the merits of new combination drenches – Zolvis Plus and Tridectin – in the fight against barbers pole.

Fiona Macarthur described effective ways to incorporate Barbervax vaccine into the sheep production cycle.

Fiona Macarthur described effective ways to incorporate Barbervax vaccine into the sheep production cycle.

Ms Maxwell recommended online sites like RamSelect to identify rams with low WEC estimated breeding values, balancing these values against other breeding priorities. A guide to drench decisions was also provided to workshop participants, along with a recommendation to access extensive sheep parasite  information at WormBoss.com.au.