CAMROSE, Alta. – It may be a few hundred years before bison ranchers struggle out of their warm beds in January to check calving cows, said a northern British Columbia bison researcher.
Unlike cattle, bison rarely calve in the cold months between January and April.
“There is evidence to support that bison rut,” said Bruce Rutley after a two-year research project on the commercial bison industry.
“If they’re going to calve, they calve from April to July that’s associated with fresh pasture,” said Rutley, who recently published the results of the project.
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The Peace Country Bison Association commissioned researchers at Northern Lights College in Dawson Creek in northeastern B.C., to do the report to help increase understanding of bison.
While cattle and sheep can often be fooled into breeding out of their normal season, using fresh grass and high quality feed, the researchers found it was rare for bison to breed out of their traditional July to September season.
By using high quality hay, bison breeding season can be extended.
“We may find we can fool animals with nutrition to breed all year round. It may not be impossible but whether its desirable …,” said Rutley.
Cattle breeding altered
It is believed cattle once had a calving cycle similar to bison, but over the years were selected to breed year round.
There are about 37,000 bison in Canada. About half of those are in the Peace region of northwestern Alberta and northeastern B.C. With an estimated 25 percent growth each year, it’s estimated by 2000 there will be more than 120,000 bison in Canada.
Rutley discovered bison were more likely to conceive on a low quality diet in the fall than on a high quality diet during the calving season from April to May.
“They waited till the rut.”
He also found the animals will not breed 90 to 120 days after calving. This occurs even with late-calving cows and prevents them from conceiving earlier next time to catch up to the rest of the herd. They also will not breed in the spring.
