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Facial eczema risk

Trying to predict what the facial eczema (FE) season is going to do requires a crystal ball and some star gazing however we do have information from our years of monitoring spores to draw from to help you be prepared.

We consider a high count being anything over 40,000 spores per gram (this affects the liver of some grazing animals straight away) and counts of 20,000sp/gm over several weeks can cause liver damage. The trend for spore growth seems to be moving earlier in the season and when we began monitoring FE spore counts in January 2023 several sites came straight in with high counts.

On the week ending 20 January our monitor site near Newbury Palmerston North recorded 75,000sp/gm and Burnand Road Taumarunui came in at 125,000sp/gm. As we did not count grass samples before this, we are unsure how long levels had been this high. Sites at Kohinui and Kumeroa had spore growth mid January and for this season we will commence our spore counting at the beginning of December in these key areas. These will be our canaries in the mine for any possible early spore activity.

Preventative strategies need to be in place at a count of 20,000 sp/gm. You can introduce zinc by bolus, daily drenching, in the water via inline dispensers, header tanks that reticulate the water supply to troughs, or at the feed pad. Early in the season zinc can be added at low levels to get stock used to the addition and increased as the risk level rises. Where these options are not available, and troughs are the sole water supply, Peta dispensers can be used directly in troughs. Water intake is variable making zinc levels in the animal less reliable.

Pasture spraying is also an option for all farming types. Spray is most effective when applied before spore counts rise as the spray does not remove existing spores. Sprayed areas remain ‘safe’ for six weeks. Spraying does not completely eliminate the risk and is generally considered to reduce the spore numbers by 60% compared to un-sprayed pasture. Pasture that already has high spore counts should not be sprayed as no benefit is gained.

Contact us to subscribe and for information on how to sample your own pasture.