For decades, cattle farmers have sent their livestock to graze on the sprawling Shamrock pasture, about 80 kilometres south of Chaplin in southwest Saskatchewan. Shamrock is where Russ Coward, a fourth-generation cattle farmer, has for years raised nearly a quarter of his cattle. It's the same place Mr. Coward's father sent his cattle.
But some time between last Monday and Friday, the cows and calves at Shamrock began to die. It's not known whether the deaths happened all at once or slowly over the course of the four days. But by the time the manager arrived on Friday afternoon, 200 of the approximately 680 cattle in a single field were dead.
The president of Shamrock Grazing Ltd., Glenn Straub, called Mr. Coward, who raced out to the field. He was met with a gruesome scene. "We seen a tragedy," he said. "We simply seen a terrible sight."
Other ranchers soon joined him, about 31 in total who have cows and calves there. "We all had the same feelings – how did this happen? How did this happen?"
Since Friday, provincial authorities as well as the local RCMP have been trying to piece together the mystery. The cause is still being determined, but the prevailing theory is dehydration and salt toxicity.
The area has been subject to drought in recent weeks, said Saskatchewan's chief veterinary officer, Betty Althouse. Officials believe this may have led to evaporation at the water source, resulting in higher concentrations of salt in the water.
"An analogy would be someone shipwrecked in the ocean," Dr. Althouse told reporters this week. "They're thirsty, they're craving water, so they're going to drink the water. But ultimately the salt water will kill them."
Many of the dead cows and calves were found clustered around one "dugout" in particular – the pools of collected rain and runoff where they drink. Investigators at the Western College of Veterinary Medicine in Saskatoon who were called in to assist have collected samples from the dugouts. Results are expected some time this week.
One of the first possibilities investigators considered was blue-green algae poisoning, a bacteria that can occur in dugouts and result in fatalities. But Dr. Althouse said that this usually results in liver damage, which wasn't the case at Shamrock. She said officials also ruled out an infectious disease such as anthrax. In those cases, cows and calves usually exhibit bloating or bleeding.
Instead, the cattle at Shamrock were found with their bellies and eyes sunken in – signs of dehydration. When investigators reached out to pinch their skin, the skin stayed in a tented position rather than returning to its usual shape.
Dr. Althouse added that, until the test results provide a definitive cause, it's "way too soon" to lay blame on any person or group.
Meanwhile, veterinarians and the ranchers have been working together to treat the surviving cows and calves – some with electrolyte and IV solutions. All of them were immediately moved to an adjacent pasture, and in the time since were moved an additional kilometre and a half away.
"It's an ongoing, emotional thing," Shamrock's Mr. Straub said. Mr. Straub himself is a farmer, and has cattle at the pasture – although not in the field in question. But many of the affected ranchers are his long-time friends and neighbours. So far, the estimated total loss to the ranchers, based on average cattle prices, is about $300,000.