Victoria worms, flies and lice update - January 2016

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

Livestock Logic Recommendations

• All producers should have administered the 1^st summer drench if required, by now (hopefully based on worm egg counts)
• Time your worm egg counts right this summer

Conditions remain dry in the south west of Victoria. There has been no significant rain so far this January and water is becoming a major issue for producers in the district.

By February all producers should have made a decision on summer drenching of their livestock. Either they would have drenched, or based on low worm egg counts decided not to drench (if you have not drenched without confirming a low egg count then I strongly suggest you check their worm status immediately). The timing of follow-up worm egg counts is important as it does vary with the season, in a dry year pasture contamination levels are greatly reduced compared to those in a wet year.

The following are guidelines for follow-up worm egg counts for producers in the south west of Victoria that have not received significant rain.

If your sheep received a summer drench, conduct a follow-up worm egg count after these periods:

• Lambs – 6 weeks
• Hoggets – 8 weeks
• Mature ewes – 10 weeks (earlier if lambs and hoggets counts are higher than expected)

If your sheep did NOT receive a summer drench because they had low worm test results, conduct a follow-up worm egg count after these periods:

• Lambs – 4 weeks
• Hoggets – 6 weeks
• Mature ewes – 6 weeks (earlier if lambs and hoggets counts are higher than expected)

Figure 1. Months of year Vs % of mature sheep that Livestock Logic recommended drenching

What this means for us in 2016

Provided it stays dry in the January­–March period, and with good worm management over this summer we can reduce the effects of worms for the 2016 winter. The key to this will be monitoring, and eliminating the worm populations from sheep with egg counts of 150+ epg. While the data above would suggest that requirements for the second summer drench will be limited this year, animals must be monitored 6–­8 weeks (6 for weaners, 8 for mature sheep) post 1^st summer drench, in February this year, to know that pastures are not becoming contaminated in the late summer/autumn period.