Thursday, March 28, 2024

Facial eczema counts in millions

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This season is stacking up to be one of the worst in decades for facial eczema as farmers across the North Island and even parts of the South grapple with high spore counts.
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Long-time AsureQuality facial eczema national co-ordinator Leo Cooney said in 43 years of monitoring spore counts for the disease this summer-autumn is one of the worst he has seen.

“I think this would be the worst since 1999. Prior to that we have records of back in the 1960s when it was quite bad too. 

“But over 43 years the spore counts are not only among the highest but have been this way for the longest period, well over six weeks now.”

Facial eczema required soil temperatures around 19C to enable spores to multiply and even approaching mid-April most regions were still at that level. 

“And we have NIWA predicting autumn will be warmer and drier so the prospects for things changing soon are not looking likely.”

Lower ambient air temperatures were not enough to make conditions safer.

Spore counts in some districts were phenomenally high. 

Morrinsville in Waikato had recorded some counts at almost 1 million but there had also been reports of one monitor site recording 2.5 million per gram in the neighbouring Matamata district.

Bay of Plenty, East Coast, Taranaki and Northland had also all reported high levels.

Vet Brian Lowe of Dargaville Vet Centre said the saving grace for many farmers over this humid period had been good feed levels and plenty of kikuyu grass, which did not sustain facial eczema spores.

“Most farmers are treating with zinc successfully and it appears to be working well with spore counts up to 200,000 which is the top end of what we are getting.”

Morrinsville Anexa FVC veterinarian Hamish Clare had clients with spore counts in the hundreds of thousands and had witnessed multiple clinical cases in recent weeks, including some cow deaths.

“All the farmers I talk to around here say this is the worst it has been for about 18 years. For many, just putting zinc into the water system is not enough and they have to mix it into feed or drench with it for better protection.”

He confirmed some farms between Morrinsville and Matamata had reported spore counts in the millions.

King Country escaped some of the worst spikes experienced further north. 

Anna Martyn of Atkinson and Associates vets at Piopio said the season had experienced lower but consistent spore counts around the 50,000 mark. They were still sufficient to inflict liver damage on stock over a prolonged period of exposure.

“Those numbers can be as bad as having a spike as they have a cumulative effect on livestock and we are starting to see that now,” she said. 

A few properties had reported 150,000-200,000 spikes but had been saved from the worst effects by having relatively high levels of feed right through the summer-autumn period. 

“It has been more widespread this season in terms of its effects across ages and types of stock affected.”

Soil temperatures were also “nowhere near” coming down to a level that would ease the risk still facing farmers.

She cautioned many farmers believed the liver of affected livestock could repair itself but often the damage was too great. 

“And one of our vets doing blood tests has detected high GGT (facial eczema indicator) levels without any clinical signs, so there is a level of subclinical impact there.”

Often the full subclinical impact would not be seen until an animal experienced the stress of calving or lambing, resulting in elevated and apparently unexplained deaths in spring.

Further south in Manawatu the disease had proved problematic one for vets and farmers because unlike farmers further north it was not usually part of the seasonal management.

In Feilding Totally Vets production animal vet Craig Dickson said farmers had been anticipating El Nino weather patterns to deliver a reasonably forgiving summer.

“But we were really dry right up until early March and there had been no facial eczema prevention done in the front end of the season.”

Spore counts in some districts were about 100,000 and had affected all classes of livestock, including alpacas.

He continued to recommend clients recording elevated spore counts treat animals with zinc.

“It will in no way mitigate any damage to the liver already done but it will help prevent any more damage being incurred.”

Even the South Island has not been immune, with districts around Takaka reporting spore counts ranging from 55,000 to 135,000 to early April.

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