While there is no cure for FE, being proactive with preventative measures can help to protect your herd, with zinc recognised as the strongest protection currently available.
The warmth of the summer season heralds the unwelcome prospect of high spore counts in pasture, resulting in increased risk of FE. In such warm and moist conditions, the toxic spores of the fungus Pithomyces chartarum start to grow rapidly amongst the leaf litter where they represent a grave danger for ruminants. Once ingested by the animal, the fungal spores wreak havoc as they move through the blood stream towards the liver creating irreversible damage along their path.
Most New Zealand cows are not getting enough zinc to maximise their defence against the disease because there is a threshold zinc levels need to reach in the blood to achieve protection, Mike says.
"What we found when going around and actually blood testing cows all over the country, is even though the farmer was giving zinc and thought they gave enough of it, something was going wrong between the bag of zinc arriving on farm and the zinc ending up in the cows, and the cows weren't actually getting the dose we would consider to be protective," he says.
"If you're not giving absolutely the right dose, then you're not getting any protection. Even though the zinc dose ramps up and up and up, there's a threshold. At some point, it crosses over and it's protective, but if it's not protective, it's not protective."
- Mike Shallcrass, Senior Veterinary Manager at Fonterra
Looking back at previous seasons when FE has hit New Zealand farmers particularly hard, Mike recalls instances where farmers were caught out because they'd only ever had a couple of clinical cases, so assumed their zinc dosing was right. However, he warns that FE is a "tip of the iceberg" disease, and that even if a farm only has a small number of animals with skin disease, there are likely to be many more sub-clinical cases, which is where the majority of production loss comes from.
"Because there were no overt signs on the outside of the animals, they thought they were FE free, but actually, there was subclinical damage happening. Without checking for liver damage, there's no way to know how bad it really is."
But farmers don't have to wait for clinical signs of FE to present themselves to assess their zinc dosing. Fonterra On Farm R&D Project Manager Paul Jamieson says ZincCheck can do the job for them.
ZincCheck takes a herd-level approach, with a bulk milk test to determine if at least 70% of the herd have enough zinc in the blood to pass across into the milk, Paul says.
"We use 70% because the natural variation we see in the herd means some animals won't be getting that high and some will be higher, but by testing the sample we can determine the level of zinc and then take that back to the research done and it will indicate whether you've got insufficient zinc, sufficient zinc, or if your herd is potentially moving into the toxic levels of zinc."
ZincCheck is only $99 per test and the first one is free for Fonterra suppliers. It's easy to book online and saves the worry of cows suffering subclinical impacts without knowing.
Head to nzfarmsource.co.nz/proactive to find out more and book your ZincCheck.
Learn more about preventing FE on farm by tuning in to our two online live Q&A sessions this February - find out more information and register ➔