Each year, beef producers are injured by overly aggressive cows at calving time. In fact, 23 people were killed by cows over a recent 15-year period in Canada. In the U.S., injury reporting by the Centers for Disease Control and Prevention reports that 14% of fatalities caused by cattle are due to beef cows with calves.

Nonetheless, research in Canada reveals that cattle producers are surprisingly tolerant of aggressive mother cows at calving time, and tend to leave them in the herd for another year. However, those same producers are much more likely to cull a cow that has mis-mothered or abandoned her calf.

These are some of the key findings of a voluntary survey of 168 Canadian cattle producers who collectively own more than 33,600 cattle. The survey was conducted at two major cattle shows and a educational cattle symposium in Saskatoon, Saskatchewan.

The survey found that roughly 6% of cows with a newborn calf will hurt a producer if given the chance. While seemingly a small number of cows, such dangerous cattle appeared on 76% of the farms surveyed. Surprisingly, however, only 13% of the cattle that producers identified as dangerous in the survey were culled for that reason.

Meanwhile, the incidence of mis-mothering reported (1.4%) was much lower than that of dangerous cattle, but mis-mothering was still seen on 56% of farms. Most prevalent in first-calf heifers, 62% of bad mothers were culled.

The survey results suggest producers may be willing to cope with a dangerous cow for a short period after calving, especially if she raises a good calf. Since revenue is derived from the sale of calves, producers are more likely to tolerate a cow that produces a good calf despite the other problems she presents.

However, producers are less forgiving of cows that mis-mother their calf (see graph). Obviously, cows that mis-mother or abandon their calf require more time and labor, which isn’t easily forgotten by producers.

Meanwhile, the dangerous cow may not require more work, other than to remember to stay away from her. It’s also possible that producers put great value in mothering behavior and some may believe that cows that are dangerous at calving time are perhaps more protective of their calf in other situations (such as when confronted with a predator).

Tolerating aggression

Surprisingly, producers are willing to keep a dangerous cow for multiple calvings. More than a third of producers admitted they believe dangerous cattle don’t change, and 22% believe they become more dangerous over subsequent calvings.

Conversely, nearly 30% of producers believe that cattle will mis-mother less in subsequent calvings, and only 7% expected them to mis-mother more often.

Producers cite genetics as the greatest factor contributing to dangerous cows, and admitted they’re potentially selecting for more dangerous cows if they keep such cows’ daughters.

Some of the most shocking results centered on cow-induced injuries and producers’ reactions to being injured. Nearly 37% of producers reported having been intentionally injured by a cow at calving. Of those injured, only 53% culled the offending animal.

Producers often rationalized the cows’ aggression, citing the circumstances or their own culpability. In some cases, the producer decided to not cull the cow because she was a good producer. As researchers, we found it surprising that producers would tolerate a cow that had injured them, despite believing the cow’s disposition was unlikely to improve over time!

We wondered whether producers’ tolerance for dangerous cows was related to  experiences with predation, as predation was a significant problem for some producers. One producer reported having lost up to 85 calves to predation over a five-year period. In fact, 37% of the producers surveyed had experienced predation over the past five years, each losing an average of eight calves.

Perhaps losing calves to predators makes producers more tolerant of dangerous mother cows; or perhaps cows exposed to predators are dangerous at calving. However, based on survey results, we found the number of calves killed by predators wasn’t related to the number of dangerous cattle.

Additional research with the University of Saskatchewan’s herd found that most cows can distinguish between predators and people around calving time, and treat them differently. We found the response to people from cows with newborns wasn’t related to their response to a predator, indicating that cows that are nonaggressive to people shouldn’t be assumed to be less protective when confronted by a predator.

This was seen firsthand by Wayne Ray of Fort Fraser, British Columbia, in summer 2010. Many readers likely have seen the photos circulating on the Internet of Ray’s cows attacking a black bear.

While checking his cattle, Ray noticed a small black bear wandering around near a group of cows. When the bear moved toward a calf, the calf’s mother charged the bear and knocked it down. Two other cows then joined in to stomp and kick the bear with their feet, heads and chests. The bear, bleeding from the nose and mouth, limped into the forest.

Ray insists these cows are extremely calm around people, even with newborns at their side. In fact, Ray keeps extensive records on his cattle and actively culls cattle even slightly aggressive. “We know too many people who have been injured by aggressive or protective cows,” he says.

Research suggests that cattle can be excellent mothers and protective of their calf from a predator without being aggressive toward humans. Producers can select for cattle that are intolerant of predators, but will remain calm around producers who must handle their newborn calf. 

Brooke Aitken earned an MS degree at the Univer-sity of Saskatch-ewan’s Western College of Veterinary Medicine, while Joseph Stookey is a professor of large animal clinical science at the same institution.