Saskatchewan's Ministry of Agriculture is investigating the death of 200-plus head of cattle and calves at the Shamrock pasture southwest of Moose Jaw.
Preliminary postmortems have been done on some of the animals, while the surviving animals were moved to another pasture.
An investigation involving the department, veterinarians and Animal Protection Services is underway.
Provincial veterinarian Dr. Betty Althouse said they believe the water could be the cause noting results of the water test are expected back today.
"It could be concentrated salts in the water," she said. "It could be sodium chloride, but it could be things like nitrates or sulfates as well. So concentrating chemicals that are already in the water. I guess one of the other things with a high number of deaths and surface water, is blue-green algae, but from the post-mortem results, that seems unlikely."
With the hot weather as evaporation occurs the salts in the water can become very concentrated.
"The animals are thirsty and they drink," said Althouse. "And because of the salt concentration in the body, they actually become dehydrated and thirstier, so they take in more. So the body quickly gets out of balance."
In the meantime, cattlemen are reminded that cattle need be checked regularly, and as often as possible in hot and dry conditions, to ensure the quality and quantity of their livestock water sources.