Sask. toxicologist says increasingly popular gopher poison poses risks to pets, livestock

A Saskatoon-based toxicologist is warning animal owners about the dangers of rodenticide.

Vanessa Cowan said the use of zinc phosphide has been growing since the federal government banned strychnine.

“This study found that not only was zinc phosphide effective in killing gophers but also a little less expensive than strychnine. So this has kind of been put forward as the alternatives for Richardson's ground squirrel control.”

Zinc phosphide is described by the Government of Saskatchewan as a “crystalline, dark powder with a garlic-like odour.”

It was first used as a rodenticide in 1911, according to the government website.

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But Cowan said the chemical can be hazardous for pets and other animals, like livestock.

“We have already received calls about animals that have been poisoned by zinc phosphide,” Cowan said.

“In this case, it was horses because one of the formulations for these zinc phosphide products is oats, and horses love oats, so if they're out scattered about, the horses are definitely going to eat them.”

One of the challenges, Cowan said, is that veterinarians do not have a method to test for zinc phosphide poisoning.

“We just don't have an analytical method available. So we can't confirm that is the diagnosis,” she told CTV News.

“Because zinc phosphide is very toxic, just like strychnine, if poisonings do occur to species that aren't supposed to be poisoned, it can be very complicated to treat.”

Cowan said that death can happen in as little as three hours.

“It's all about just following labelled precautions as best as one can. And just following those to the tee and using the product as intended.”

The government website advises the wearing of gloves when dealing with rodents that have been poisoned, uneaten bait, or empty containers.

“Avoid contact with skin, do not breathe in dust or fumes, do not leave in unprotected piles and avoid feed and other foodstuffs to prevent contamination,” the province says.

Cowan said people needed to also be aware of the dangers the chemical can cause to humans.

“If a poisoning does occur, the gas that is produced in the animal's stomach is actually very toxic to you and me. So, for example, if someone's animal gets into it, and you are transporting that animal to the hospital, with your car windows closed, you could be inhaling that toxic gas that they are producing, and it's called phosphine gas.”

For this reason, she said it was important to warn vets if they are working on an animal that may have been poisoned.

“Despite the best intentions of people placing baits and whatnot, things do happen.”