Victoria worms, flies and lice update - June 2018

Hamilton: Andrew Whale, Livestock Logic (a.whale@livestocklogic.com.au)

Livestock Logic Recommendations

  • Worm egg counts are generally remaining quite stable for western Victoria.
  • We are seeing a massive difference in egg count results depending on the timing of summer treatments and monitoring over the summer. Drenching after mid-January has had a great impact on minimising pasture contamination levels.
  • Regardless of the pressure until now, we always see a spike in egg counts from now until the end of spring.
  • Continue to monitor weaners and lambs every 2–3 weeks and mature sheep every 4–5 weeks throughout the winter and early spring.

Winter has arrived in the south west with some much cooler weather over the past few weeks, although the conditions for the June lambers have been mostly pretty mild. Pasture growth rates have been very good on the back of a great autumn break and we have had the opportunity to take plenty of feed into the winter, unlike most other livestock areas in Australia.

Recent egg counts are showing that the worm pressure to date is not too bad. This is pleasing as after huge egg counts in November and December last year I was concerned there would be a residual population of worms/larvae that would cause considerable challenge this past autumn. There is no doubt that we will see increased challenge the deeper into winter we get, but to date, worm egg counts have been very stable. Many weaners are only now getting to moderate worm levels that suggest their first drench since the autumn break is approaching. There have been cases of considerable worm burdens, but these have mostly been where summer worm management has been less than ideal.

We are seeing a strong relationship between the timing of summer drenches and current egg counts. Those that drenched early in the summer and failed to monitor or drench in January generally have much higher worm levels in their sheep. In comparison, those that were aware of high egg counts in January and successfully minimised pasture contamination over the 3–4 dry months we experienced are reaping the rewards.

The chart below shows the current worm challenge compared to that over the previous 2 years.


This chart shows that the challenge to date this year is not as bad as last year, but regardless, there is strong evidence that the worm challenge will only increase over coming months as worm levels increase on pasture. So continue to monitor weaners and lambs every 2–3 weeks and mature sheep every 4–5 weeks throughout the winter and early spring.