BY: SANDRA TAYLOR
A pilot study investigating the potential of a groundbreaking facial eczema (FE) tolerance test is underway with initial results expected early next year.
The purpose of this pilot study, led by AgResearch’s Dr Axel Heiser and funded by Beef + Lamb New Zealand (B+LNZ), is to test the feasibility of a laboratory-based test to determine an animal’s tolerance to the toxin associated with FE.
Heiser says the goal is to find a test for either blood or saliva, that would indicate an animal’s resistance or susceptibility to FE.
This is based on the premise that as well as causing toxicity to the liver, sporidesmin, the toxin produced by the pasture fungus Pithomyces chartarum, is also toxic to other cells in the body, such as those found in blood and saliva.
Heiser and his team have been carrying out a number of experiments with blood cells and now have shown toxicity on blood cells. They are beginning to do the same with cells prepared from saliva, which is a bit more technical, but saliva samples are a lot easier to take, as they are for the CARLA test.
“What we’re trying to see is what sporidesmin does to those cells.”
By carrying out a detailed analysis of treated and untreated cell cultures, they are hoping to find a fingerprint or profile of sporidesmin toxicity.
The discovery of that fingerprint, hopefully by the end of January, would mark the end of phase one of the study.
If phase one is successful and funding can be secured, the next phase would be to look for this fingerprint in animals (sheep, cattle and deer) with FE.
They will also look at herds known to be either resilient or susceptible to FE and compare fingerprints.
Heiser says while nothing is fast in science, he is hoping that by the end of next year they will have a good idea whether a blood or saliva test is going to work.
They will then work with a commercial partner to make a fast high-throughput test that is affordable and accessible to commercial breeders and farmers.
An easy and affordable test would make the testing of females feasible, significantly speeding up the breeding of FE resilient animals.
The need for this type of test was driven by farmers and researchers (the Facial Eczema Working Group) who have been providing industry leadership around this issue for a number of years.
At the other end of the equation, Heiser is working with B+LNZ to develop a research programme looking at why New Zealand has a problem with FE.
While the toxin is found in other parts of the world, it only causes significant production-limiting disease in NZ – and no-one knows why.
“We’ve always focused on the way it behaves in the animal rather than the way it behaves in the pasture, and we may be looking at a simple solution for FE.”
- Beef + Lamb New Zealand
