Conservation Officer Len Butler said this year, black bears were responsible for 47 to 50 per cent of all predator attacks on cattle in the Cariboo region.
"It's made us wonder why so many black bears have figured out that calving was such a good source of food," he said.
Butler suspects after the light winter and early spring, bears came out their dens earlier their year, and that may have lead to the increase in the number of attacks.
Usually, attacks by coyotes, cougars and wolves are more prevalent, though Butler didn't provide exact figures.
Although black bears can often be spotted grazing on grass on the side of the road, they are omnivores and will attack other mammals for food.
"They definitely are opportunists," he said.
Ranchers are trained to spot which predator killed a calf by looking at the carcass, said Butler.
"Basically, black bears will bite on the back of the shoulder blades. It's more of an aggressive kill," compared to wolves, which will sometimes bite a calf's hindquarters to hamstring it, he said.
Under the B.C. Wildlife Act, ranchers are allowed to kill a bear that is on their property and a menace to domestic animal, but must report it to the conservation service, said Butler.
"Our concern is what that's going to look like in the fall when generally most of our black bear complaints come in to the Conservation Officer Service."