No simple answer in Pimelea simplexin puzzle

Researchers deliver latest Pimelea news at AgForce animal health days


Beef
Pimelea toxin researchers Dr Mary Fletcher and Dr Diane Ouwerkerk have presented their latest findings around western Queensland this week. Picture - Sally Cripps.

Pimelea toxin researchers Dr Mary Fletcher and Dr Diane Ouwerkerk have presented their latest findings around western Queensland this week. Picture - Sally Cripps.

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For western Queensland cattlemen dealing with a spike in Pimelea poisoning in their stock, there is no immediate solution in sight despite some promising advances in research.

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For western Queensland cattlemen dealing with a spike in Pimelea poisoning in their stock, there is no immediate solution in sight despite some promising advances in research.

According to Pimelea toxin researchers Associate Professor Mary Fletcher, from the Centre for Animal Science, Queensland Alliance for Agricultural and Food Innovation, and DAF's Dr Diane Ouwekerk, the poison found in Queensland's main strains might go by the name simplexin but its makeup is anything but simple.

The two women were part of an AgForce animal health forum that visited Blackall and Yaraka earlier this week and was scheduled for Windorah on Wednesday.

While AgForce north west regional manager Vol Norris said plans for the information day had been formulated months ago, the surge in reports of Pimelea poisoning from as far west as Birdsville had made the sessions especially relevant.

According to local Biosecurity Queensland stock inspector Dan Burton, producers were taking some "big hits" with reports of up to 60 head dead in one area where the grower didn't think the toxic plant was growing.

"The conditions for Pimelea and plenty of other poison plants are perfect at the moment - I'm betting I'll get another phone call before the day is out," he said.

Those conditions include autumn rain after a dry summer, sandy country and disturbed ground.

A map showing the distribution of the main Pimelea species in Australia, courtesy of Australia's Virtual Herbarium.

A map showing the distribution of the main Pimelea species in Australia, courtesy of Australia's Virtual Herbarium.

The main management technique at the first sign of poisoning, usually dark diarrhoea, is to remove the stock from the paddock - "if in doubt, get them out" in Mr Burton's words, especially as it was hard to avoid grazing on Pimelea plants when it was growing up through pasture.

It's this conundrum, that the plant is a native that can't be eradicated and that animals can't be totally prevented from grazing on it, that has centred MLA and producer-funded research on finding a way to stop cattle from absorbing the toxin once they've eaten it.

It could mean that probiotics - live bacteria that enable the gut microbiome to produce beneficial compounds for the body to use - might not just be the latest weapon for the human health food community but for the bovine world as well.

Dr Fletcher likened it to the process that now allows cattle to fatten on leucaena, which contains a toxic amino acid, mimosine.

"Biopolymers are being developed for the controlled delivery of low dose Pimelea toxin, to bolster beneficial rumen bacteria without adverse toxin effects, but we're not there yet," she said.

Dr Ouwerkerk said her team was up to fermentation 8 and had identified 18 different species of rumen bacteria.

"As we've both indicated, simplexin is a bugger of a compound," she said. "And it's a dog eat dog world in the rumen. My feeling is, when a weaner goes down, it's partly because their rumen is still developing."

She said the team would be keen to hear from growers with cattle that had been through Pimelea outbreaks and had survived, in order to sample their gut bacteria.

She also indicated they weren't putting all their eggs into the rumen basket, which was why the toxin-absorbing biopolymer strategy was also being looked at.

Among the exciting possibilities being explored were bolus manufacturing with 3D printing, and tests with bentonite, biochar and other absorbents, Dr Fletcher said.

This backed Mr Burton's assertion that ingesting charcoal, via burnt timber, seemed to help affected cattle he'd seen.

"My old man was a stockie at Mitchell so I've picked, packed and cut up Pimelea for years, and I'm still working on it," he said.

The problem is said to cost the cattle industry up to $50m in "bad" years such as 2019 is shaping up to be, and affects a third of Australia's grazing land.

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