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Courtesy of Megan Rogers, Sheep Connect NSW

This season will be remembered for many reasons, and the sheep worm story is but one of a long list! (flies, floods, grain harvests that were anything but smooth, plus more!)

The pressure from worms that producers are experiencing in their sheep flocks has in some cases caught many off guard, and where producers were expecting things to be busy managing worms, producers have been surprised by the relentless pressure.

Many are finding that their pastures are so heavily contaminated, that their worm management is severely impacted. This is where close monitoring and careful pasture management show their value. Sheep worms are a costly aspect of any sheep operation. Much of the cost associated with worms comes from production losses, often unseen. Internal parasites are the second highest cost to the Australian sheep industry, with around 20% of the cost to industry borne in prevention, and estimated at a total cost of $450 million nationally.

Controlling internal parasites can be tricky, and seasonal conditions, class of livestock among other things make controlling worms difficult to understand. In a season like this the key things to know are:

  • Monitoring is critical - get the WORM EGG COUNTS (WEC's) done and keep an eye on what's going on in your sheep
  • Use an EFFECTIVE product that contains no less than 2 active constituents
  • Use the CORRECT DOSE - drench to the heaviest in the mob - and divide the mob if you have a wide range of weights - this will avoid over and under dosing
  • Conduct a FOLLOW UP WORM EGG COUNT to check that your treatment has worked effectively - do this 10-14 days after treatment

In a season like this, where an absence of hot dry weather is keeping conditions favourable for ongoing contamination of pastures, which gives rise to animals taking these larvae and eggs in whilst on the pasture, there is a good case for using a long acting product - but these products need to be used judiciously to avoid the development of resistance. (single active drenches as found in injectables place a lot of selection pressure on the worm population for resistance - which is why they need to be used in combination with a PRIMER (given at the same time the LA is administered) and a TAIL CUTTER administered once the numbers of worms in the mob begin to increase (monitoring to get the timing of this right is needed). Be sure to consult your trusted animal health advisor for specific advice regarding the use of long acting products.

Worm control in your sheep operation can seem to be complex (and it often is!), and product choice is one of the main issues that we hear people struggle with. In essence - use a combination of actives, and keep an eye on the witholding period, for both meat and milk, as well as the export slaughter interval - to ensure that you do not impact on sale opportunities.

Sheep Connect NSW has hosted a large number of webinars on worms and their management over the past year, and we have complied the recording links of these into a single document, along with some other very helpful links to the ParaBoss website that will help you this season. You can view it here.

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