What are the spores doing? Facial eczema-beat it before it beats you

What are the spores doing? Facial eczema-beat it before it beats you
By Rebecca Smith, Veterinarian, Anexa Vets Morrinsville

The Facial Eczema season is upon us and the best way to stay ahead of the game is to keep an eye on those spore counts. Spore counting on our monitor farms has officially kicked off. To find out what spore counts are doing in your area, visit www.anexa.co.nz/fe and sign up to our weekly email updates. To get a more accurate picture of what the spore counts are doing on your farm, you can collect your own pasture samples and submit them to your clinic for testing.
  • When collecting pasture samples cut the grass with scissors as close to the base of the sward as possible.
  • Collect ten samples from a paddock. These samples should be evenly spaced out, taken across a diagonal of the paddock.
  • At the end of your collection, you should have enough grass to entirely fill a bread bag. Note, a 200g sample is required to run the test.
  • Multiple paddocks should be assessed individually to get an accurate representation of what is happening on your farm.

What are the critical spore count levels?

The toxic dose range for spore counts varies between cows and sheep.
  • Moderate challenge for cattle >30,000 spores/ g of pasture
  • High challenge for cattle > 60,000 spores/ g of pasture
  • Low-moderate challenge for sheep> 40,000 spores/ g of pasture
  • High challenge for sheep > 80,000 spores/ g of pasture
Zinc supplementation should be in place before spore counts reach moderate levels. This is because ongoing exposure to low-moderate spore counts will also result in toxicity over time.

Prevention is better than the cure- what can you do?

Reduce the consumption of spores:

  • Spray pastures with fungicide: this needs to be done before spore counts reach 20,000 spores/g. Fungicide must be sprayed on lush growing pasture. All areas that can be grazed must be sprayed. This can last up to 4-6 weeks if performed correctly.
  • Provide alternative feed sources to grass over the risk period.
  • Avoid grazing paddocks where there is accumulation of dead plant material.
  • Maximise post grazing residuals (avoid hard grazing).

Zinc treatment:

  • Zinc can be dosed in a variety of ways:
    • In the water- easiest but often least accurate (not suitable for sheep or youngstock)
    • In feed – better than water but dosing is dependent on how much each animal eats
    • Oral drench- accurate but the most labour intensive
    • Slow release boluses- accurate and less labour intensive
  • Check that your zinc dosing method is working by getting your vet to check the blood zinc levels from at least 10 members of your herd. This should be done 2-3 weeks after zinc supplementation has been introduced at full rates.
  • Choose your starting date wisely: ideally zinc treatment does not last more than 100 days to reduce the potential for chronic zinc toxicity.
For more information about zinc treatment and recommended dose rates pick up one of our guides from your local clinic or visit www.anexa.co.nz/fe

It is important to use a combination of prevention strategies for a fail-safe protection plan. Talk to your vet about what prevention plan is best for you.


Date Added: Tuesday, 9th February 2021


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