Facial eczema: Study aims to understand the risk across New Zealand

A facial eczema sample collection kit ready to go.

A new three-year study is under way to understand the risk of facial eczema (FE) across New Zealand, as part of a broader Beef + Lamb New Zealand-led programme called Eliminating Facial Eczema Impacts.

Beef + Lamb NZ principal scientist of animal health research Cara Brosnahan is leading the study.

Eliminating Facial Eczema Impacts is backed by $20.7 million in funding over seven years, with contributions including $9m from Beef + Lamb NZ, $8.3m from the Ministry of Primary Industries through the Sustainable Food and Fibre Fund, and the remainder from 14 partners across the sector.

“The study had 202 participating farms from all over New Zealand in the first year and we hope to build to 350 farms,” Brosnahan said.

“Sixty-six farms are in the South Island, which isn’t traditionally a FE area.”

Pasture spore counts usually start in January, but this study doesn’t want to assume when the spores start appearing or that all years will be the same.

They will be collecting samples of sheep faeces starting in October and continuing through to May.

Sheep poo collection

Each farm samples from a mob of sheep that will be on the farm from October to May and follows them taking 10 faecal samples every two weeks.

Both dairy and meat sheep are in the study.

Methods for collection of fresh samples vary between moving the mob into a paddock corner and waiting for them to poo, or arriving at the paddock early and waking the mob up and collecting their first poo of the day.

“Each farmer has a box including all the kit required to collect 10 individual samples in 10 different pottles so we know multiple animals are used,” Brosnahan said.

“These are couriered to Awanui Veterinary in Palmerston North for analysis.”

Out collecting samples after a good 24 hours of much-needed rain. Photo / Baylee Hodges

Extensive other data from each farm are also collected.

This includes weather data from the MetService virtual climate station, pasture information, paddock aspect and altitude, irrigation, sheep age and sheep breed.

“The samples are tested for faecal FE spore counts and results [are] sent back to the farmers, usually within seven days,” Brosnahan said.

“This year, we arranged a webinar with the farmers in the study to discuss early results and answer any questions.

“The yearly results will be analysed by Ingenum, shared with the study participants and then made publicly available.”

Year-one findings

Beef +Lamb NZ principal animal health research scientist Cara Brosnahan is leading the study.

After one year, fungal spores were found in every region except the west coast of the South Island.

Brosnahan explained Pseudopithomyces species spores looked very similar under the microscope, so it was hard to establish whether it was the type that produced sporidesmin, the mycotoxin that causes facial eczema when ingested, or one that was harmless.

“We are developing a polymerase chain reaction (PCR) test with dnature diagnostics & research ltd to genetically identify which type the spores are.”

Information from the study provides a more accurate picture of the locations of high-risk facial eczema areas in New Zealand so farmers can be better informed about the disease in their region.

Ingenum will also try to use the data to build a predictive model to provide farmers with risk prediction information.

Psuedopithomyces species spores under the microscope. Photo / Diana Lee, Landcare Research

“Establishing the higher-risk areas earlier in the FE season allows farmers to plan their prevention programme before their livestock are exposed to the toxin.”

Pasture management, including moving away from ryegrass (which the fungus favours) in the facial eczema season to other fodder and keeping stock from grazing the high-risk pastures in the fungi season are physical steps that can be taken.

Zinc for prevention is widely used in dairy cattle but not as commonly used in sheep.

Breeding facial eczema-resistant genetics into sheep flocks remains the most sustainable option for farmers, but it takes several seasons to achieve results.

“We are very grateful to see so many farmers physically involved in this study and providing us with samples for this study,” Brosnahan said.

“B+LNZ works to ensure that our research is conducted in collaboration with farmers, researchers, and rural professionals.

“It is crucial to have a farmer perspective throughout the development of farm strategies to FE.”