When driving by cows grazing along the highway, it seems like the animal’s highs and lows of life are based on where they’ll get their next meal. But researchers believe that when cows experience particularly stressful situations, like being stalked or attacked by predators, they can suffer from post-traumatic stress disorder.
An Oregon State University study finds that cows that have suffered trauma or stress-related illness experience more difficulties getting pregnant in comparison to cows that haven’t. For much of the population this doesn’t mean much, but for ranchers it means lost profits.
“Cattle that are exposed to wolf depredation will produce less calves, which translates to a reduction in the amount of food produced for human consumption,” says David Bohnert, director and associate professor at OSU’s Eastern Oregon Agriculture Research Center in Burns.
When predators, like wolves, kill or injure cattle, ranchers document these losses. But researchers found that with animals that experience PTSD, ranchers still experience loss: pregnancies go down, calves are smaller and more prone to sickness.
In the last 20 years wolf populations have grown in the West. An OSU economic analysis predicts that in worst case scenarios, ranchers can lose up to $261 per head of cattle due to trauma: lower pregnancy rates, weight loss, increased watch over herds, etc.
John Williams, an extension service agent at OSU and author of the analysis, says people tend to focus on the dead animals, which can be emotionally difficult. But from a economic stand point, the traumatized cows are costing ranchers more. And there doesn’t seem to be a way to reverse PTSD in the cattle.
“Once a traumatic event has occurred the damage is done and will be difficult or impossible to reverse,” Bohnert adds. “(But) there is currently no research of which I am aware that has evaluated this aspect.”