Western Ranchers have to deal with a lot of wildlife interaction in their widespread range operations.  Western livestock tend to suffer more predation than their eastern and more concentrated counterparts closer to civilization.  As a result these Western cows tend to be more protective of their young. 

One Wildlife Society Bulletin documented 851 cases of Black Bear predation on livestock from 1974-1979.  81% of those were on Cattle.  The majority of black bear kills are calves. 

Texas A&M extention makes this statement on their Bear Predation Page:

Predation by black bears on livestock is most common in spring and summer. Limited food sources in early spring and failures of wild berry and nut crops during summer months are probably major contributing factors…

Black bears will attack adult cattle and horses but seem to prefer sheep, goats, calves and pigs. They may break the neck or back of prey with blows from the paws, but normally they kill by biting the neck and shoulders. Claw marks are frequently found on the neck, back and shoulders of these larger animals. Multiple kills of sheep and goats are relatively common, possibly because they are easy prey.

Whether by accident or design, bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals.

One Rancher in British Columbia saw first hand how cattle that have suffered predation loss from bears will become very protective, especially of their calves.   a thirteen photo sequence documented the encounter

A couple of evenings ago, Wayne went out to check the cows and saw a very strange sight and was able to photograph the event. A black bear approached our cow herd which turned out to be a very big mistake on his part.

The blonde and white Simmental cow we know as I-12 went right for him. She is a very good cow, a very attentive mother and about 12 years old. She’s in her prime and knows that bears are bad news.
She and tried her best to mash him into the ground.
ribs out of the deal at the very least.document this summer. It is amazing.

There are a couple of photos where the bear is biting I-12’s leg and clawing her face but she is not giving up. Her stiff tail shows how agitated she is. Wayne said all the cows were bawling, the bear was squealing, the calves were running around with their tails in the air.

A younger cow, R-55, an Angus-Cross cow, age 7, is helping her out as best she can. It is an incredible photo to see
two cows at once trying to crush the bear.

I looked up the calving records of both cows who are so aggressive in these photos and they are both good, calm cows around us and have given us no troubles whatsoever. I’ll have to add in my notes that they have a very distinct dislike of bears.

We’ll be watching I-12 over the next few days to see if she needs treatment for infection. I don’t know how willingly she’ll come to the corrals for treatment, but she might not have a choice.

Finally, the bear decided to vacate the area. We
thought he’d be dead for sure, but there was no sign of him the next day.

We’ll have to keep an eye out for eagles in the
trees or flocks of ravens flying up. We’re sure he’s got some broken

Wayne couldn’t believe his eyes when he
witnessed this ruckus. This is another once-in-a-lifetime
photography event to add to all the others he managed to document this summer.  It is amazing.