Cows that witness wolf attacks suffer PTSD-like symptoms

CORVALLIS, OR (KPTV) -

Cows that survive encounters with wolves may suffer from symptoms similar to post-traumatic stress disorder, according to a new Oregon State University study.

Researchers said they were told by ranchers that such cows are more aggressive, sickly and eat less. The memory of a wolf attack can also lead to decreased pregnancy rates and lighter calves for those animals that do give birth.

To measure the stress of a wolf attack on cows and estimate its lingering effects, researchers simulated a wolf encounter with 100 cows. Half of the cows had never seen a wolf, while the others had been part of a herd that was previously attacked on the range.

Cows were gathered in a pen scented with wolf urine while prerecorded wolf howls played over a stereo. Three trained German Shepherds, which closely resemble wolves, then walked outside the pen.

Researchers found that cortisol, a stress hormone, increased by 30 percent in cows that had previously been exposed to wolves. They bunched up in a corner, formed a protective circle and acted agitated.

http://www.kptv.com/story/24899097/osu-study-cows-that-witness-wolf-attacks-suffer-ptsd-like-symptoms