Worm Heat Map – September Edition

With August data presenting the final egg counts for winter, the northern tablelands are showing moderate worm challenge.  Several larval cultures submitted from the region have indicated a high Trichostrongylus challenge, a reminder that, while often forgotten about during the barber’s pole season, this is an important worm that affects sheep liveweight gain and wool growth. A wet winter has certainly contributed to its higher prevalence this year. When infection with this worm is dominant, thresholds for treatment need to be much lower in this region.

On the western slopes, the worm challenge remains much lower. Be prepared for a quick jump in egg counts in the event of September rainfall. Any spring rainfall will allow for barber’s pole worm development.

Worm egg counts remain at similar levels to last month, at the lower end of the range for this region. Thresholds for treatment in this region during winter range from 150 epg for young sheep, rams and pre-lambing ewes, to 250 for other ewes and wethers. Good rainfall in the region continues to keep scour worms active.

The eastern side of this region has seen a slight decline in the average worm egg count compared to  the previous month but remains in the yellow category. The western part of the region has seen a large jump in average WEC, leap frogging to orange. Just over 20% of samples returned very high worm egg counts above 750 epg. At these levels, some lambs will be taking a little longer to get to market.

The average WEC in western Victoria has increased to 411 epg for August, now showing  as orange on the map. Winter rainfall, combined with lambing ewes and weaned lambs, has seen the worm challenge rise. With many pastures still providing lower kg DM/ha than usual, monitor sheep WECs regularly and treat as required.

In other parts of Victoria, while fewer WECs have been conducted, they are showing low levels of worm challenge.

While worm egg counts have jumped in western Victoria, worm challenge in the south-east of the state remains categorised as low,  shown in green.  Although, like last month, 10% of counts are above 250 epg, with a couple of counts above 750 epg.

In Western Australia, the southern region’s worm challenge continues its run (shown as yellow) and is now joined in this category by its northern neighbour, the central region. As predicted, this region has seen its average worm egg count more than double on the back of some winter rainfall. Good news is that sampling in the region continues to grow, so hopefully many farmers have jumped on control options quickly. Spring is a period of tactical drenching to ensure productivity benchmarks are met.