Published on 26/01/2022
While fatal in worst case scenarios, it can wreak havoc at sub clinical levels keeping just below even the most vigilant farmers’ radars.
Tauranga-based Adama New Zealand commercial manager Bryce Simpson says with no cure for FE farmers are forced to be proactive. A mixture of herbs in pastures, dosing with zinc prophylactic products, monitoring spore counts, breeding using FE tolerant animals, and careful grazing management are all employed to minimise risk.
Alongside those measures is the use of Adama’s broad spectrum fungicide Chief, which is proven to reduce the escalation of toxic spore numbers.
Caused by the sporidesmin toxin produced by the spores of the fungus Pithomyces chartarum, FE thrives in the warm, moist conditions in the thatch in the lower sward of the pasture. When the spores are ingested the toxin they release causes damage to animals’ livers.
The highest levels of FE tend to be in the mid to upper North Island; Bay of Plenty, Waikato, King Country and Taranaki, with the highest risk period being January through to May.
At temperatures from around 18 to 20 degrees with 90 per cent relative humidity spores can multiply very quickly, but Bryce Simpson says it is wisest not to make risk assumptions based on weather conditions alone.
“A farmer in Whanganui was having real trouble finishing lambs. He was grazing them in a little valley which created a microclimate as the dew tended to linger there. He’d never seen any clinical symptoms of FE. And he couldn’t work out what the issue was. Finally, he was persuaded to spray with Chief and he found that the lambs put on an additional 2-3 kgs each. Once that spore count was brought down, finishing weights were a whole lot better.”
Simpson says in adult stock underlying FE can also be problematic. “Even when FE is sub clinical, it can take up to 18 months for animals to recover their full potential.”
Reduced milk production in dairy herds and reduced fertility in sheep resulting from sub clinical FE have been reported with estimates of up to 25 per cent productivity loss over a lifetime.
To borrow a phrase, Simpson says he always recommends ‘going hard and going early’ with Chief. “It’s best to treat pasture in anticipation of danger. When spore counts start to approach 20,000 per gram of leaf, we’d recommend spraying then.”
Simpson says the spores will still be present, but their rate of multiplication will be significantly slowed, and build-up will be prevented for up to six weeks. He says animals can cope with spore counts of up to 20,000 but beyond that point liver damage will occur. “Once you’re over 100,000 the horse has well and truly bolted.”
When using Chief, he says it is important to ensure coverage of all areas likely to be grazed, including under and through fences, hedges and trees. A surfactant should also be added.
“In early February treat enough pasture for 14 days grazing then treat additional areas as required, timed so stock will be grazing 7-10 days after spraying.” In an emergency, stock can be grazed 24 hours earlier.
Simpson says if heavy rain occurs within three days of treatment, the pasture should be resprayed. During danger periods, stock should be grazed in treated areas only.
Bryce says in addition to efficacy Chief has the benefit of being very cost effective. “It’s a really important tool in helping fight the pathogen.”
New stock of Chief is expected in time for the FE season.
For more detail visit www. adama.com or talk to your local Adama commercial manager.