Cattle producers in drought areas should monitor their herds with extra vigilance this summer to protect against diseases caused by poor feed and reduced water quality.
Dr. Chris Clark, a large animal veterinarian from the University of Saskatchewan’s Western College of Veterinary Medicine, says dry weather and hot summer temperatures can result in unexpected herd losses, especially in areas where producers rely on surface water sources such as sloughs and dugouts.
In parts of southwestern Saskatchewan, for example, the risk of sulfate poisoning could be unusually high this year.
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Drought conditions in the Prairies has led to an decrease in water quality, and producers are being advised to closely monitor water quality for their animals.
Sulfate poisoning usually occurs in the summer when water sources begin to dry up and sulfate levels in the water become elevated.
The risk is often augmented by poor pasture conditions where cattle are more likely to graze on drought-tolerant plants, such as kochia, which are also high in sulfates.
“It’s basically sulfur toxicity,” Clark told producers at a May 1 stock growers workshop held at the college.
“If you have a situation where you have the potential for high sulfate levels in your water and plants like kochia are plentiful because you’re in a drought area, this could push you over the edge.”
Losses caused by sulfate poisoning can occur quickly.
Producers with cattle on pasture might notice a dead animal and attribute the death to a twisted stomach, lightning strike or some other cause.
If sulfate poisoning is the cause, however, losses can mount quickly, killing several cattle before a proper diagnosis is reached.
Clark recommended that cattle producers in high risk areas recognize the potential for losses and conduct a post mortem on unexplained deaths in the pasture.
The disease can be hard to detect because water test results from the same source can vary significantly from month to month, he added.
A water sample taken from a slough might have acceptable sulfate levels in the spring but months later, when water levels fall and minerals in the water become concentrated, the sulfate levels could reach deadly levels.
“If you run into (problems) in the pasture … you need to get your water tested immediately,” Clark said.
Ideally, sulfate levels will be below 1,000 parts per million.
Levels between 1,000 and 4,000 ppm might not be deadly but losses are still possible, especially if pasture conditions are poor and high sulfate plants are plentiful.
“Certainly if the water has sulfate levels over 4,000 ppm, the cattle shouldn’t be drinking it.”
Water samples sent to an accredited testing lab can usually produce results within 24 hours.
Sulfate poisoning causes neurological dysfunction in cattle.
Animals with elevated sulfate levels display symptoms similar to those of classic polio in cattle.
These include problems walking, poor balance, blindness, shaking and stargazing, where an animal lifts its head straight backward and points its nose toward the sky.
Classic polio, which is caused by thiamine or Vitamin B1 deficiency, can often be treated by adding massive amounts of thiamine to feed rations. Cattle with sulfate poisoning will not respond to thiamine supplements.
Clark added classic polio is more common in feedlots and among cattle that are on high grain diets.
In the pasture, cattle showing signs of neurological dysfunction are more likely to be suffering from sulfate or lead poisoning.
Clark urged producers not to be complacent when they discover a pasture death. Producers should never assume that a long-standing water source is safe.
“That’s what can be so frustrating about (sulfate poisoning),” he said.
“You might have been using that same slough or dugout for years and never had a problem, then all of a sudden sulfate levels rise and animals start dropping. If you have sulfate poisoning the answer is pretty simple. You’ve got to find another water source …. It can be a hassle to haul water, but it’s the only solution.”
Anthrax cases have also become more common recently.
Northeastern Saskatchewan had a rash of anthrax cases two years ago, but the disease has also affected herds in Alberta and southwestern Saskatchewan, around Swift Current.
Anthrax cases often arise when a wet spring is followed by a dry summer.
“We can’t predict anthrax with any degree of accuracy but … if you see animals dying for no apparent reason, it’s got to be high on the list of possibilities,” Clark said.
Producers in high alkali and drought prone areas should be particularly vigilant.
