Dr. Jason McGillivray says that, in the Kamloops, British Columbia area, the problems started in the 2021-22 winter when there was lower feed quality followed by a dry spring.
“During the pregnancy checks of the fall of 2021, we noticed that more cows were going to be calving later, and the following year, more of those cows were calving later still,” Dr. McGillivray says.
In that area, November 2023 brought a big snowstorm, which disrupted ranchers’ extended grazing programs, which normally would go into January.
“In some of the herds, they had to feed earlier with lower quality hay, and those cows were in poor body condition,” he says. The multiple punches of later calving and an early winter followed by drought meant that open rates were up.
In his area, Dr. McGillivray said another contributing factor in some herds was wolf predation through the breeding and grazing season, which put cows under tremendous stress.
In Brooks, Tabor and Lethbridge, Alberta, Dr. Blake Balog says data from his practice indicated that, on average, open rates were about 12 percent for cows and 14 percent for heifers.
“In that mix, we had some pretty high highs and pretty low lows,” he says, adding that shorter breeding seasons had up to 90 percent bred and, on the other end, some groups went to 20 percent open.
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