Worm Heat Map – July Edition

Worm egg counts across the northern region remain relatively low heading into winter. The eastern zone averaged 140 epg, with the western zone slightly higher at 168 epg, both within the green category. While western QLD is shown in red, a very small sample size limits interpretation for this region. The Darling Downs region continues to have a low worm challenge, with the average WEC being 126 epg. 

This reflects a subdued winter challenge overall, with dry conditions over summer and early autumn likely limiting larval development. While barber’s pole worm risk is reduced at this time of year, winter-active scour worms remain relevant, particularly in susceptible sheep classes.

Central NSW continues to show the most notable worm challenge nationally. The eastern zone averaged 286 epg, placing it in the yellow category, while the NSW high rainfall zone recorded a significantly higher average of 522 epg.

This indicates that while much of the region is carrying manageable burdens, higher rainfall areas are maintaining elevated infection pressure into winter. In contrast, the western zone remains very low at 15 epg, reflecting minimal challenge.

Ongoing vigilance is warranted in the higher rainfall country, where winter-active species are likely contributing to the burden.

Southern NSW has eased considerably, with both zones now sitting in the green category. The eastern zone averaged 139 epg and the western zone 55 epg, indicating a relatively low overall challenge. This suggests that earlier seasonal pressure has not persisted into winter, although localised variability is still possible depending on paddock history and stock class.

Victoria shows a mixed picture. South West Vic has lifted to 208 epg, moving into the yellow category and indicating a moderate level of winter challenge. By contrast, the Wimmera remains low at 79 epg, reflecting minimal parasite pressure.  The pattern is consistent with winter rainfall regions, where black scour worm and brown stomach worm can contribute to ongoing burdens through the cooler months.

South Australia remains at a relatively low level of worm challenge. The south-east averaged 140 epg, placing it in the green category.  While regional averages are low, the spread of results indicates some mobs are still carrying moderate burdens, reinforcing the need for continued monitoring.

Western Australia continues to show low-moderate challenge, particularly in the winter rainfall zones. The southern region averaged 335 epg, while the central region averaged 122 epg.,.  Although slightly below autumn levels, this indicates ongoing parasite activity through winter, consistent with seasonal expectations in WA systems.

Tasmania data indicates a low challenge (green) for both zones.  In the high rainfall zone, worm challenge has dropped from the moderate challenge seen at the end of autumn.

The June data suggests most regions are entering mid-winter with manageable worm burdens, but with several important watchpoints:

NSW: Higher rainfall remains the key risk area, with elevated WECs persisting
WA and south-west Victoria: continue to show moderate winter challenge
Most other regions: currently low risk, but conditions can change quickly

At this time of year, WormBoss guidance emphasises:

Regular worm tests to confirm burden levels
Close monitoring of young sheep and lambing ewes, which are more susceptible
Awareness that scour worms dominate in winter rainfall environments
Aligning treatment decisions with regional thresholds and seasonal risk

Maintaining monitoring through winter is critical to avoid unexpected build-up heading into spring.