MOOSE JAW — Cattle producers in Saskatchewan are facing higher open rates than usual, and a leading livestock veterinarian says drought, mineral deficiencies, and poor nutritional timing are all likely culprits.
Dr. Nathan Erickson, an associate professor at the Western College of Veterinary Medicine, delivered a detailed talk during the Saskatchewan Stock Growers Association’s 112th AGM in Moose Jaw recently. His presentation, “Timing is Everything: Cows, Grass, and Fertility,” explored how reproductive performance in cow-calf herds can be significantly affected by feed quality, mineral access and stress during peak lactation.
Erickson said a number of producers have reported open rates surpassing 10 per cent — well above the five per cent benchmark veterinarians aim for.
“Ten per cent is kind of in that area where we start saying, ‘We’re at or over 10 per cent — is something going on?’” he said. “Maybe we could look to find a reason why it’s happening and possibly make a change before it becomes a real problem … our goal is to try not to load as many cattle off that trailer as possible, right?”
An “open rate” refers to the percentage of cows that do not become pregnant during the breeding season, often indicating underlying health, nutrition, or management issues in the herd.
Erickson walked attendees through a recent herd investigation in southern Saskatchewan that saw a 26 per cent open rate. He found two key contributing factors: poor body condition during breeding, and copper deficiency linked to high sulphate levels in the water.
“We got thin cows, and we got low copper; there’s our problem. We need to get more groceries (feed or nutrition) to these cows …,” he said.
He emphasized that subtle energy shortfalls during calving and early lactation can delay reproductive recovery. As a result, many cows may not begin cycling until after bulls are turned out, pushing conception into the second or third breeding cycle — or missing it entirely.
“If something happens in that time period where they’re not quite getting enough nutrition to meet those energy demands for lactation, it’s going to take a toll on the reproductive system quite quickly,” he said.
One of Erickson’s most practical pieces of advice: keep track of calving distribution. Simply writing down how many calves are born each day can offer critical insights into breeding success and nutrition issues.
“If you’re doing more than that, great. If you’re not doing anything, if you do one thing, just write down how many calves are born each day during calving season,” he said. “It gives you a lot of powerful information.”
Erickson also flagged copper levels as an ongoing concern in Saskatchewan due to naturally deficient soils and widespread high sulphate water. Blood tests can help, but he noted that liver biopsies give a more accurate picture of stored copper.
“High sulphate water is going to tie up the copper, and the cattle are not going to be able to absorb that copper and store it or even utilize what they’re eating,” he said. “We would have needed to respond to that probably at least two months before turning out the bulls.”
Sulphate concentrations above 1,000 ppm in livestock water sources can interfere with copper absorption and lead to deficiencies affecting cattle health and fertility, as per the Saskatchewan Ministry of Agriculture. Sulphate levels under 500 ppm are generally considered safe, and levels ranging from 500 to 1,000 ppm may start to affect sensitive animals.
His takeaway for producers: be proactive, track herd performance, and adapt feeding strategies early — especially in dry years.
To learn more about the Saskatchewan Stock Growers Association, visit SKStockGrowers.com.
