The owner of a 1400-hectare farm comprised of flat paddocks and medium to steep hill breeding county spoke to Hawke’s Bay Today about how he was resolving the issue, but wanted to remain anonymous due to the stigma and impact on his business.
He said he had tested his sheep for 20 years by conducting faecal egg count tests, but early in 2024 was “blindsided” by results that came back as ‘triple drench resistant’.
A report released earlier this year show he’s not alone. Results for the first seven months of 2024 showed that triple drenches (BZ/Lev/Aba) were failing on 34% of New Zealand sheep farms.
“I had done one three years ago and I was all good.
“This particular one I did in late February, early March, was an absolute disaster in the space of three years it really turned on its head.”
The tests are done by collecting samples from fresh poo and taking it to the vet to be examined.
Drench resistance in worms can cause no weight gain in sheep and increase the likelihood of death. Photo / Michael Craig
Vets told the farmer worm counts of any higher than 200 would affect a lamb’s productivity, but the egg counts for his flock were in the thousands — at its worst an egg count returned a result of 9000.
“It was just a shambles.”
He said the first half of 2024 was “a perfect storm” with a shortage of Zolvix and Startect drenches that could help him.
He said he was now looking at two to three years to pull himself back with a change in grazing management of his sheep and how he buys and sells lambs.
“The big one is not having lambs on the same country all year round.”
He said while that sounded like an easy fix, the contour of his farm meant all the weaned lambs went on the flat country while ewes were put on the hills.
“The steep hill country doesn’t suit lambs ... they are rougher paddocks with a bit of scrub, blackberry, gullies and steep faces, so it’s a lot harder to muster them when they are freshly weaned.”
He said it was also important to monitor stock rotation as this would help mitigate the worms that live in the ground.
“You drench the lambs and put them in an area where you farm and when they come in for the next drench, shift them to another area.”
He said the reason for this was for the ewes with the “susceptible worms” to come in after the lambs and mix the “resistant worms”.
The aim was to breed a worm susceptible to the drench again.
“We are trying to farm worms and in a way, it is the complete opposite of how the previous generation was taught.”
The worms have a lifecycle of 21 days and rely heavily on the right temperature and moisture conditions to grow.
“They will crawl up the grass, are ingested by the sheep and grow into an adult worm in the gut and that’s where the damage is done.”
The farmer said the worms could latch onto the gut lining, and damage was worse in lambs because they had no natural immunity, unlike adult sheep in good condition.
The farmer said the cost to drench his sheep now was high, but he wasn’t against the expense, saying it made him think twice about the use.
He advised anyone questioning their position not to ignore the issue, and to monitor during pre and post-drench and get advice.
“The worst thing you can do is bury your head in the sand and that’s why I brought an advisor on board.”
Beef and Lamb extension manager Mark Harris said the complicated challenge presented to farmers was increasing in noticeability.
He said it was important to understand the parasite’s cycle and adapt to manage it.
Harris said Beef and Lamb was running well-attended workshops across the region for farmers about parasite challenges.
“We have a little saying in our game that farmers learn best off farmers.”
He said drawing on the knowledge and experience of others was useful in understanding how best to create change and find solutions.
“We are finding out more every day, and the parasite is a very smart little bug that is quite adaptable.”
Michaela Gower joined Hawke’s Bay Today in 2023 and is based out of the Hastings newsroom. She covers Dannevirke and Hawke’s Bay news and loves sharing stories about farming and rural communities.
