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Three horses dead after Shuswap horse rescue receives shipment of toxic hay

Vets and owners warn to watch for symptoms of nitrate poisoning
Three of the horses in care at Salmon Arm’s BC Horse Angels. Luke, in the middle, died of nitrate poisoning the week of Dec. 18 2022, from tainted hay. Two other horses died during the week as well. (BC Horse Angels/ Facebook)

BC Horse Angels rescue in Salmon Arm suffered the loss of three horses due to a shipment of toxic hay.

Belinda Lyall, founder of BC Horse Angels, said the first horse died on Sunday, Dec. 18.

“It was such a shock, I found her dead in the field out of nowhere,” said Lyall. “It’s your worst nightmare.”

Lyall said she had no idea what had caused the death and went about her day, keeping an eye on the other horses. By that evening, a second horse suddenly become extremely sick, shaking and heaving breaths with discharge pouring from its nose.

A veterinarian wasn’t able to get to the rescue until Sunday evening, and Lyall said they didn’t know what to do, treating the illness as an infection and prescribing an antibiotic. After consulting with another vet, the decision was made to let the young, healthy, two-year-old horse take its chances. The horse died later that evening while the vet was still there. Lyall said both vets were baffled and she was left with no further suggestions.

On Monday, Dec. 19, Lyall came back to work at the rescue and found another horse had gotten sick, though symptoms were not quite as bad as what she’d seen the day before. Lyall was soon visited by another vet who had more experience, she said, and decided to investigate the hay the horses were eating.

The vet decided the horse was suffering from nitrate poisoning but had never treated it before, saying it was rare. After doing research, the vet then drew the horse’s blood and saw it was a very unusual dark colour, which is a telltale sign of nitrate poisoning.

The vet had a vial of the medication to treat nitrate poisoning, methylene blue, in his truck. He had saved it since 1989 because it’s very hard to get but also rarely needed, said Lyall.

The antidote is supposed to be given slowly through an IV drip, but in the cold weather and accounting for the age of the medicine, the vet decided to inject it all in one needle, which Lyall said was a risk they were willing to take.

Within five minutes, the horse was visibly better, no longer shaking or displaying symptoms. After fifteen minutes, the vet drew more blood and the sample was a normal red colour again.

“It was miraculous,” said Lyall. “I stayed and watched him for a few more hours, he was quiet and has seemed fine ever since.”

Nitrate poisoning is caused when too much fertilizer builds up on plants or when plants like hay become stressed and accumulate more nitrates than the plant is able to turn into proteins and amino acids. After two years of extreme heat and droughts, hay plants all over B.C. have been stressed and are at risk for accumulating nitrates.

When excess nitrates are ingested by animals, the bacteria in nitrates breaks down into nitrites, enter the bloodstream and change the capability of the blood to carry oxygen. Animals’ bodies then begin to suffer from oxygen starvation and they can die within hours.

A third horse died later in the week, after Lyall had separated the horses from the poisonous hay. She suspects some got mixed in with other hay bales but she said on Thursday, Dec. 22, that all the horses now seem fine and the hay has been completely replaced.

Lyall said she wants to warn horse owners of the danger of nitrate poisoning and inform vets that it is happening. She said she has received other calls about horses dying and people never having heard of nitrate poisoning since sharing the story on Facebook. As well, she said people are wondering why the methylene blue medication is so hard to get.

Nitrate poisoning can present like pneumonia, Lyall said, and owners should be aware that with colic or shock horses’ gums will turn pale, but with nitrate poisoning the gums will look darker than usual. The onset can be sudden, said Lyall, and she wants to prevent this from happening to anyone else.

The poisonous hay from BC Horse Angels is currently being tested, as well as a blood sample from one of the afflicted horses.

BC Horse Angels is dealing with extensive bills after the vet visits and having to buy new hay to feed the horses unexpectedly. If you would like to donate to help with the rescue’s expenses, send an etransfer or a Paypal payment to

READ MORE: B.C. Horse Angels seek to end practice of horse slaughter

READ MORE: Grant for Shuswap donkey refuge will help reduce cost of veterinary visits


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Rebecca Willson

About the Author: Rebecca Willson

I took my first step into the journalism industry in November 2022 when I moved to Salmon Arm to work for the Observer and Eagle Valley News. I graduated with a journalism degree in December 2021 from MacEwan University in Edmonton.
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