Back to State Outlooks

Victoria worms, flies and lice update - July 2016

VIC WormBoss Worm Control Programs

VIC WormBoss Drench Decision Guides

Hamilton: Andrew Whale, Livestock Logic (

Livestock Logic Key Recommendations


  • Weaners, every 2–3 weeks throughout winter
  • Adult stock, every 3–4 weeks
  • Pre-lambing ewes,
    • Immediately, if not done for a month, and
    • recheck 3 weeks before the start of lambing

There has been some wonderful rainfall in south west Victoria so far this winter, with good run-off filling dams left mostly empty after two dry summers. It is wet, but it is winter, so we cannot complain. Apart from 2–3 days of horrific weather in mid-July, it has been reasonably good for lambing.

The combination of low worm levels in stock due to the dry spring/summer, low carry over dry feed in paddocks, and good pasture growth in May and June, have resulted in healthy stock better able to manage worm infestations. Many mobs lambed down in early winter without the need for drenching as worm egg counts at pre-lambing, and at lamb marking in already lambed mobs, were low.

Disease investigations identified worms and associated secondary bacterial infections as the primary cause of deaths of weaners. This scenario is expected to continue throughout winter and emphasises the need for frequent and consistent monitoring of worm burdens, particularly of light-condition Merino weaners.

In the graph below, the numbers of weaners drenched from January to July this year was remarkably low reflecting the dryness of the season, but the number predicted to require drenching in August is expected to rise sharply. 

Figure 1. Percentage of weaner sheep drenched (January-July 2016). 
Source: Livestock Logic Laboratory.

In summary: Stay vigilant with worms this winter and importantly, monitor light weaners fortnightly, all other weaners every 2–3 weeks, and mature stock at least monthly, until feed and environmental conditions improve in the spring.

For July 2016 state outlooks, please follow the links below:
Back to State Outlooks