Toxoplasmosis can be "devastating" on sheep farms, New Zealand Veterinary Association sheep and beef branch president and vet Alex Meban said. Photo / RNZ, Ruth Kuo
By Farah Hancock of RNZ
Feral cats are responsible for spreading toxoplasmosis, which can cause “abortion storms” on sheep farms. Methods of control, such as annual culls, have come under fire from animal welfare advocates.
Warning: This story describes the killing of animals, including an image of a trapped feral cat.
It was over beers in a woolshed that the decision was made: feral cats would be part of the North Canterbury Hunting Competition.
“We just sort of looked around and went, ‘Yeah, might as well’,” organiser Matt Bailey said.
“Unbeknown to us, it would go off like a powder keg within a matter of days of posting something on social media.”
What the farmers thought was a no-brainer decision to add another pest to the competition shocked cat lovers.
The backlash was immediate and sponsors of the rural fundraising event came under attack on social media.
But, if anything, the outcry from animal rights advocates made the decision to include feral cats even more popular with farmers and sponsors.
“They poked the bear and it’s probably backfired for them because it’s gotten people off their asses and out there hunting,” Bailey said.
Three years on from the woolshed conversation, the cat category remains popular.
This year, contestants entered 326 dead cats for the June weighing-in weekend.
Bailey suspected the real number of feral cats culled was higher.
Farmers ran out of freezer space to store the bodies, he said.
“I knew guys catching 10 a week and they weren’t keeping them.”
This year, there was no backlash from animal rights advocates, which Bailey reckoned was down to increased awareness of the damage feral cats do.
It is one topic where hardcore conservationists and farmers find common ground.
Feral cats decimate native wildlife and pose a disease risk to farm animals and dolphins.
They are found on all types of farms, according to Bailey.
On dairy farms, feral cats are often spotted near milking sheds or haysheds. They are also commonly seen near offal holes, or in Bailey’s case, at lambing time, in paddocks eating afterbirth.
He said he had not heard anyone report an increase in rat numbers after removing cats, adding that if rats do appear, bait stations can be used.
And to critics who argue that trapping, neutering and releasing feral cats is better than culling them, Bailey had a blunt response: “They’re killing our native birds and not shagging them.”
There is no official estimate of how many feral cats there are in New Zealand.
The number of 2.4 million is often cited, but some believe the true number is far higher.
Their number created a disease risk for every farm in the country, New Zealand Veterinary Association sheep and beef branch president and vet Alex Meban said.
Toxoplasmosis is carried through cats and spread through their droppings.
Tens of thousands of oocysts produced by the parasite can be in cat poo, which, when accidentally ingested by sheep via grass, hay or water, can be infectious.
Toxoplasmosis can also be passed to humans through contaminated soil, water or unwashed vegetables, and is particularly dangerous during pregnancy or to people with compromised immune systems, but it also affects dolphins and farm animals, such as sheep.
For farmers, there are no outward signs of the disease until lambing time.
That is when an “abortion storm” can occur, which is when more than 5% of ewes lose lambs.
“It can be devastating,” Meban said.
Last season, one farmer realised he had lost 30% of foetuses during scanning.
“We asked the question about wild cats, the answer was yep, there are lots of wild cats. They hadn’t really considered it to be an issue until scanning time.”
Lamb losses like this can mean the difference between breaking even or not over a year for a farmer.
There is a vaccine for the disease and Meban said it only took one season of heavy lambing loss to convince a farmer to vaccinate their flocks.
The vaccine costs between $3 and $5 and offers lifelong protection.
If lambs were worth $150 each, Meban said, it did not take much for the vaccine to pay for itself.
Vaccination should go hand-in-hand with reducing cat numbers on farms, he said.
A Federated Farmers pest survey last year, which had about 700 responses, found 37% were actively managing feral cats, the organisation’s meat and wool chairman Richard Dawkins said.
The survey showed 2868 cats were culled by farmers over a 12-month period.
Anecdotally, Dawkins said he had heard the number of feral cats was on the rise.
He also pointed to the increased risk of toxoplasmosis and its impacts on native wildlife.
“I have one farmer report to me that on a braided riverbed, they had a cat take out 90% of a fledge of young birds in a colony that was on a river island,” Dawkins said.
The cat ate 60 of the chicks of a black-fronted tern colony.
Farmers have told him live-capture traps are the most effective, but these need to be checked daily, which is a time-consuming exercise for farmers with large blocks.
Cats need to be included in regional council pest management plans, but without extra funding for staffing, “it just becomes words on paper to be honest”, Dawkins said.
Increased public education would help, as would support for desexing domestic cats.
The problem increases around holiday periods, which could be caused by people dumping pets, Dawkins said.
“They’re a pretty lovable animal and people may think they’re releasing them to run free and have a good life, but they may not understand those implications,” he said.
The Animal Justice Party was one of the groups that expressed concern at the inclusion of feral cats in hunting competitions.
Committee member Bridget Thompson said the party saw all animals as sentient and objected to the killing of feral cats.
The line between companion cats, strays living close to communities and feral cats can be tricky for people to discern.
“The problem there is that if people cannot make the distinction, you get self-proclaimed eco-warriors in the cities, thinking that if they go out and kill any cat community or companion, they are doing a good thing.”
Trapping and desexing is also not the preferred option, Thompson said. Instead, she would like a biological solution.
“We would like to see serious science into interrupting the fertility cycle.”
Thompson acknowledged nothing like this existed at present.
Predator fences were also an option until science catches up.
“There’s a range of non-violent alternatives to current methods of population control,” Thompson said.
– RNZ