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Victoria worms, flies and lice update - December 2014

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

Conditions remain dry in the South West of Victoria. Luckily stock prices remain buoyant giving producer’s confidence in the livestock sector and making purchasing large amounts of fodder a bit easier.

Given that the 2014 spring has been similar to the climatic conditions of spring/summer 2012, I have reviewed Livestock Logic’s worm egg count data from January 2013, which (given current climatic conditions) is likely to reflect what we will see in the early stages of 2015.


Graph 1: Review of worm data from 2013 and 2014

Months of year Vs % of sheep that Livestock Logic recommended drenching

This highlights the differences between a wet spring/summer (‘13/’14) and a failed spring (‘12/’13) in terms of pasture contamination levels and exposure of stock to worms. Focussing on the January to May period we see that with a dry spring and summer period egg counts were very low by January and remained low right through until they started to increase steadily in July, that year we did not get a break until late May. In contrast, this year (2014) egg counts remained high in Jan-March, reduced in April-May but then sharply increased from June onwards.

The key differences in these years were

  • Spring and early summer rainfall
  • Quantity of dry standing carry over feed in summer and autumn

The above led to a huge difference in the amount of worm eggs on pasture at the time of the autumn break and thus stock challenge in winter and spring.

What this means for us in 2015

Provided it stays dry in Jan-March (typical of a winter-dominant rainfall region) with good worm management over summer this year we can reduce the effects of worms for the 2015 winter and spring. The key to this will be monitoring and eliminating the worm population from sheep with egg counts of 150+. While the data above would suggest that second summer drenching requirements will be limited this year, animals must be monitored 6–8 weeks (6 for weaners, 8 for mature sheep) post 1st summer drench, in February this year, to know that pastures are not getting contaminated in the late summer/autumn period.

Benalla: Tricia Veale (triciav7@bigpond.com)

In this area of North Eastern Victoria we have had very low rainfall recently and it is very dry underneath. Some areas however were suddenly targeted by very severe storms and hailstones, which have damaged crops and fruit. The local rainfall for November was 61 mm with 19 mm so far for December. The water level in the rivers and dams has decreased with moderate levels remaining.

Farmers have been very busy with harvesting and most have finished. Some crop yields have been lower than normal due to dry conditions.

Farmers are now checking their animals for flystrike. Flies are very prolific after recent small rains.

Worm egg counts are continuing at moderate levels in this area.

Liver fluke eggs have been located in some animals. So, if you are on a property where fluke are present, then it is a good idea to get a test done for these too.

We note that quite a few local farmers have recently drenched sheep without first testing them to make sure it is required. These farmers are in a very real danger of creating drench resistance problems on their property. It is really important not to give sheep the first summer drench unless they really need it.

When purchasing animals at sales it’s virtually impossible to find out the truth about the drench resistance status of the vendor’s property.

Quite a few farmers have accidentally introduced worms onto their properties because they fail to quarantine drench newly purchased animals straight off the truck with a combination of drench groups.

Also with the rapidly increasing incidence of worms that are becoming resistant to drenches it is vital not to import other peoples’ resistance problems.

Happy Christmas to all! I wish you a very productive and successful 2015!