Cattle suffer damage from wolves far beyond predation

This is a significant impact, but ranchers who have been dealing with wolves have reported additional costs and losses when wolves are present. These costs include weight loss, lower pregnancy rates, reduced gain for calves, more sickness, and an increase in management costs.

Oregon studies confirm, wolves have long-lasting negative effects on cattle

Most discussions about the impact of wolves on livestock producers focus on depredation losses, both confirmed and unconfirmed. The rule of thumb is that for every confirmed kill there are probably eight more unconfirmed losses.

This is a significant impact, but ranchers who have been dealing with wolves have reported additional costs and losses when wolves are present. These costs include weight loss, lower pregnancy rates, reduced gain for calves, more sickness, and an increase in management costs.

David Bohnert, beef extension specialist and ruminant nutritionist at Oregon State University (Eastern Oregon Agricultural Research Center, at Burns, OR) and coworkers decided to do studies looking at these issues. After wolf introduction into Wyoming and Idaho, and expanding wolf population into Washington and Oregon, there was a growing perception and anecdotal reports by beef producers that the damages they were seeing went far beyond actual death losses.

“The Oregon Beef Council helped fund some research that Renaldo Cooke and I proposed. John Williams, Wallowa County Extension agent (now retired) was part of this work as well. Our first study used cattle from Idaho that had been exposed to wolves for several years, with numerous verified cases of wolf depredation. In contrast, cattle here at our Research Station at Burns, OR, had never experienced wolves, so we decided to compare the two groups of cattle,” he told WLJ.

“We brought in 50 cows from the Idaho operation and used 50 of our cows, running them together as a common herd. We managed them all the same and ran them through our working facility weekly for two months so they would get used to it. This gave the Idaho cows time to settle in and become comfortable here. We wanted to look at stress effects, so we gave them time to become familiar with our facilities, handling, and people—to remove that potential source of stress,” he explains.

Initially, the cattle were sorted by temperament (flighty or not) and their identity blocked so the data could be analyzed scientifically and statistically.

“We had five groups of 10 cows from each herd. We thus had five groups from the wolf-exposed cows and five groups of the non-wolf-exposed cows. This allowed us to compare two groups (one group from each herd) at a time, to evaluate differences in stress and behavioral responses,” he says.

At that point, the preliminary data was collected, looking at temperament, body temperature, and the levels of cortisol (a stress hormone) in the blood.

“Then we exposed them to a mock wolf encounter. This consisted of a howl box—emitting the sound of wolves howling—cotton swabs soaked with wolf urine placed near the cattle, and we brought in pseudo wolves (German shepherd dogs).”

The dogs were walked past the corral, to create the presence of a large canine.

“We did this for about 20 minutes with each group. Then we brought the cattle to the chute and re-evaluated all of the variables we’d looked at earlier. At that point we saw that the nervousness (temperament score) rose much higher on the cattle that had been exposed to wolves in the past. Blood cortisol levels also went up at a greater rate than in the naïve cattle. Body temperature went up in both groups of cows because we were handling them and moving them around, but it went up much higher in the cows that had previously been exposed to wolves.”

In short, the cattle with wolf experience became visibly stressed and agitated.

The lasting impact of wolves on cattle in pictures

A series of photos documenting the initial Oregon State University wolf experiment. Cattle that had never experienced a wolf attack were curious about the experiment’s “mock wolves” while experienced cattle showed dramatic fear and defensive behavior, as well as dramatically higher levels of stress hormone in their blood.

Researchers at Oregon State University conducted a pair of experiments involving cattle with and without experiences of wolf attacks. Pictured here, wolf-naive cattle are curious about the German Shepherd Dog (mock wolf) walking by their pen during the initial study. They are cautious but show no overt fear, instead keeping ears and eyes up on the new thing in their area. • By Dr. David Bohnert, Oregon State University Extension
By comparison to the wolf-naive cattle (pictured top right), the cattle that had experienced a wolf attack (foreground) bunch up tightly and struggle to get into the center of the small herd when exposed to the mock wolves in the study. This is a clear and dramatic fear response in cattle.    
By Dr. David Bohnert, Oregon State University Extension

You can see the full article at Western Livestock Journal