Cows whose herd comes under attack by wolves remember the experience and show symptoms similar to post-traumatic stress disorder, Oregon researchers say.
That’s according to a study from Oregon State University and publicized Thursday. Reinaldo Cooke, an associate professor and animal scientist based in Burns, conducted the research, which appeared in the Journal of Animal Science in late March.
When wolves attack a herd of cattle, Cooke said in an interview Thursday, the surviving animals’ life experience is “completely altered” by the event. Animals become jumpier around humans and pets, the cows give birth to smaller calves, and the animals are more likely to get sick.
It doesn’t take much to trigger the memories of the wolf attack. “Those cows are grazing out there, man,” Cooke said, “and they know what wolves can do.”
“Every time they hear wolves howling, even if it’s two miles away, they go through the stress process,” he said. “Every time they do that, they don’t eat, they’re always on alert.”
The fact that a wolf attack would be traumatic to an animal isn’t a novel idea, Cooke acknowledged, but said he now has scientific evidence of its effect.
Cooke’s study was paid for by the Oregon Beef Council, an industry group based in based in Portland that represents ranchers.
Oregon Wild, a nonprofit environmental advocacy and conservation group, criticized the use of PTSD to describe nature. “PTSD is a very serious condition afflicting millions of Americans,” Oregon Wild said in a statement. “It is incredibly disrespectful for it to be used by an industry association to make a point that should be obvious to anyone who has ever seen a nature documentary: prey don’t like predators.”
OSU took 10 cows from a commercial herd in Idaho that survived a wolf attack to Burns for the project. They also gathered 10 Burns-based animals that had never seen a wolf.
The animals were separated into different pens scented with wolf urine. Wolf howls were piped in over a stereo.
Three trained dogs that resemble wolves – two German shepherds and one collie-Alaskan malamute – paced outside the corral during the 20-minute study period.
“The cows from Burns couldn’t care less,” Cooke said in an interview.
In the news release about the study, Cooke said the Oregon cows “showed no signs of agitation and actually approached the dogs.”
“They also didn’t have biological signs of PTSD, according to PTSD-related biomarkers evaluated in their blood or brain tissue,” he continued.
But the Idaho cows did seem effected. Their blood work showed biomarkers indicating extreme stress. None of the Idaho cows had been wounded or attacked by wolves directly.
Cooke said the study’s results are normal, and simply document a fact of life in the wild. “We have to think of the welfare of the cows, the wolves, and the producers,” he said, citing the cattle owners.
“The wolves deserve their space, the cows deserve their space,” Cooke said, “We just need to know what’s going out there.”
The study comes as state wildlife officials are considering some changes to how the threatened canine is managed in Oregon. While the wolf population was stagnant in 2016, in terms of the number of animals counted by state biologists, officials observed a significant increase in the number of wolf attacks on livestock.
Oregon removed wolves from the state’s endangered species list in 2015, but they remain under federal protection in western Oregon. The wolf’s primary activity is still concentrated east of U.S. 97, U.S. 20 and U.S. 395.
