Be aware worm burdens increase after dry spells followed by rain

Be aware worm burdens increase after dry spells followed by rain
We have finally seen some much-needed rain but the days have remained warm. These are the perfect conditions for worms to flourish. The life cycles of worms rely on adults living in stock and producing eggs that contaminate pasture through manure. These eggs hatch on the grass and develop through three larval stages before being eaten by other stock.
The eggs need temperatures of 8-15oC depending on the type of worm and 10-15mm of rain over 4-10 days to hatch. Some areas of the Waikato have definitely experienced these conditions lately. Up until now, the drought has been useful in destroying many of these eggs and parasite burdens will have been low without irrigation. We expect this to change rapidly with a bit of rain.

The weather is not the only reason autumn is a high risk for worms. With little grass and lots of supplements eaten directly off the ground, stock are grazing the wormy base layer more and more. This means there are more worms, surviving longer and stock are eating more of them. We have all seen the devastating effect high worm burdens can have on weight gains but at the severe end, these can become a welfare issue. We recommend continuing to act now to prevent levels getting this bad.

So what can we do to reduce the impact?

  • Start faecal egg counting in sheep every 4-6 weeks
  • Blood testing in cattle can be a substitute as FEC’s are less reliable
  • Drench based on the results of these
  • Move young stock to ‘clean pasture’ that hasn’t been recently grazed
Please speak to your local Anexa vet if you would like help developing your parasite control programme.




Date Added: Monday, 6th April 2020


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