Clark says earlier research on the direct effects (death and injury losses) due to wolf predation on cattle indicates the impacts are underestimated. Some cattle just disappear; a pack of wolves can consume a carcass overnight.

“However, no one had researched indirect effects of wolf presence on rangeland livestock production. These indirect effects may much more greatly impact livestock producers than death and injury losses. Indirect effects of wolves on livestock range-use patterns impact foraging efficiencies, disposition and stress levels,” says Clark.

Those effects could cascade to affect cattle diet quality, nutritional status and disease susceptibility. Wolf presence also may indirectly affect — and reduce — calf weaning weights and cow body condition in the fall, perhaps resulting in increased veterinary care and supply costs, and death loss to disease.

OX Ranch’s Anderson says he weighs and assesses his cows when they’re collared in the spring before turnout; he does the same when they come off the range to move to winter pasture. Collars are then removed.

“We’re seeing cows come home a full body score less than in the past. With a mature cow, each score is about 100 lbs.,” he explains. This translates into extra feed costs to get cattle through winter.

He says the herd’s conception rate has also plummeted. “With our herd health program, mineral and protein supplement, there’s no reason for this other than the wolves. What normally would be a 90%-95% conception rate in our herd has gone as low as 82%,” Anderson reports.

Besides actual kills, additional animals were severely maimed. “We spend a lot of time doctoring these, and end up with a bunch we can’t sell because they’re crippled,” he says.

In one week of summer 2012, he says nine calves had wolf bites. “The calves may live, but we have to doctor them. We believe the pack’s alpha female is using calves to teach the pups how to hunt,” Anderson says. Four young cows in the first-calf heifer group had big abscesses behind the shoulder and/or above the flank area, due to infected wolf bites. The wolves are playing with these animals.

“We’re also seeing changes in the way cattle are using the range. They bunch up more against fences, which the wolves use to corner them,” Anderson says.

Wolf predation usually stimulates a change in cattle use patterns, Clark says. Anxiety over wolves may prompt cows to shift from high-quality foraging areas to low-quality ones. “Cattle may get up on an open hillside where they can see farther, to detect if wolves
are approaching,” he says.

“Cattle under threat bunch up, standing in open areas where they feel safer,” Clark adds. “These areas become dry and dusty from concentrated trampling, which can lead to respiratory disorders — especially in stressed cattle that are more vulnerable to disease,” he says.

If cattle are being bred on the range, all these factors work toward decreasing the number of cows that get bred on time, or come up open in the fall, Clark says. Late calves alter uniformity of the calf crop, which adversely affects the price received, and may also affect the number or quality of heifers a rancher is able to keep; the future productivity of the herd is adversely affected.

There are also changes in cattle temperament. Cows that were calm and easy to handle become difficult. “In one Idaho herd, a wolf followed cattle down to the calving areas, and the cows were very aggressive trying to protect their newborn calves. The rancher couldn’t tag a calf without being attacked by the mother cow,” Clark says.

Anderson says that before wolves arrived, his cattle were easy to work with dogs. “Our cow boss of more than 25 years has good dogs, and the cattle respected them. Now the cattle chase the dogs, and we can’t use them for herding anymore. Without them, it’s extremely difficult to move cattle in this steep, rugged country,” Anderson explains.

The OX Ranch calves in late May through June, and calves are branded at the fall gathering. “The calves are 350-400 lbs. by that time; when they come into the corral, they’ll size you up and take you,” he says. They’re totally focused on defending themselves, attacking a dog or person.

There also are more handling-related injuries to cattle, along with increased frequency of bunching and flight events, Clark says.