The Idaho Rangeland Resource Commission recently reported wolf-involved depredation cases set a record high for the fiscal year ended June 30 and are continuing at a strong pace.
By Brad Carlson
Capital Press
Cascade, Idaho, rancher Phil Davis said wolves killed three of his cows in early August. Separately, three other cows were killed nearby.
“We lost three cows to wolves this last week, three days in a row,” said Davis, who for decades has studied Idaho wolf issues and has been outspoken about wolves’ impacts on livestock. The kills were Aug. 2-4 on Davis Cattle Co. property.
USDA Wildlife Services confirmed the three cows were killed by wolves, as well as three other cattle on property close by, Public Affairs Specialist Tanya Espinosa said. In necropsies to determine the cause of death, the agency found bite marks and associated hemorrhaging, she said.
“There was extensive trauma, particularly on the nose and face, on all three cattle, plus other places on the body,” Davis said.
“We are on track this year to lose as many or more cattle than we ever have to depredation,” he said Aug. 7, referring to Davis Cattle. “We are at nine right now. In the typical year it has been five to seven for the whole year.”
He expects the Long Valley, a high-altitude stretch of meadows and mountains from Cascade north through McCall to see more depredations than ever this year.
The Idaho Rangeland Resource Commission recently reported wolf-involved depredation cases set a record high for the fiscal year ended June 30 and are continuing at a strong pace.
Scott Lake, Western Watersheds Project Idaho director, said this reflects Wildlife Services’ new method to confirm livestock deaths. “It is the reporting method and the Wildlife Services outreach efforts, encouraging ranchers to report more livestock deaths as possible depredations even where there is no outward sign of predation.”
In Cascade, Davis runs his cattle on private, irrigated pasture, so livestock kills are in short grass and easier to find than they would be in trees or thick brush, Idaho Rangeland Resource Commission spokesman Steve Stuebner said. In remote trees and brush, it could take weeks or even months to find the carcass of a potentially wolf-killed animal, if it is found at all, he said.
In forest environments, “quite often, bears will consume the carcasses after they are killed by wolves and before ranchers or cowboys can find them,” Davis said.
Canine marks on a hide confirm a wolf killed a cow or calf, he said.
“But sometimes there is so little trauma they are not confirmed,” Davis said. “But I believe they died of myopathy.”
Myopathy is muscle dysfunction or weakness. Davis said it has been a factor in wolf-related deaths, even where on-carcass evidence is minimal or lacking, as the cow later falls some distance from the encounter site.
Lake said Western Watersheds disputes that field investigations can confirm deaths were caused by myopathy related to wolves.
Davis said he has asked Wildlife Services to “encourage their research arm to research myopathy so that confirmations can be more clinical” and less open to subjective interpretation.”
Gordon Murdoch, University of Idaho associate professor of animal physiology, said reliably confirming myopathy as a factor in cattle deaths from wolf attacks will depend on test accuracy, the number of tests taken over time — and across different time periods and situations — and the ability to validate results.
Traumatic myopathy, as opposed to genetic or hereditary myopathy, results from physical injury or a change in pathology, he said. Low oxygen carrying capacity, low hemoglobin levels or an illness are non-injury examples of traumatic myopathy.
“It’s possible we could identify some animals that were captured and killed where one of the underlying causes is myopathy,” Murdoch said. “I wouldn’t want to say it wouldn’t provide useful information, but it’s not going to answer the whole story.”
Livestock producers are losing fit, less-fit and very young animals to predation, he said.
“There might be some animals suffering from myopathy, and they would be susceptible to predation. But there are multiple factors,” Murdoch said. Snow, fences and other barriers hinder even the fittest cattle, “so it’s possible a very fit animal becomes prey to wolves that hunt in packs.”
Exertion can be a factor.
“If you are continually under threat, that can result in exhaustion and make you more susceptible,” Murdoch said.
Whether myopathy or another condition exists, “anything that causes reduced capacity for muscle performance in the animal is going to hinder their ability to escape,” he said. Myriad factors — such as other illnesses, excessive heat and reduced nutrition intake — “can participate in their susceptibility to predation.”
“People don’t realize what’s happening,” Davis said. “This management is not working. We can’t continue to get more and more depredations.”
Stuebner, of the Rangeland Resource Commission, said there have been many more wolf kills of livestock on private land than federal and state wildlife managers expected when they first placed wolves in central Idaho under Endangered Species Act provisions in 1995 and ’96.
Wildlife Services’ recent findings are similar, Espinosa said Aug. 7. The agency since May 31 confirmed 27 wolf depredations in the Cascade and Donnelly areas, the vast majority of which were on private property, she said.
Necropsies are important in determining the cause of death because wolf behavior differs, Espinosa said. Wildlife Services in the last few years has noticed some wolves are attacking and not feeding on animals killed — one reason producers should inform the agency of the death of any livestock so a necropsy can be performed even if obvious signs of wolf predation are not present, she said.
Lenders assume about 2 percent of the herd will be lost each year from any cause, Davis said, so an increase in wolf depredation stands to boost percentage losses to levels that could make the business unsustainable. He and other Idaho ranchers in the past year or so have discussed wolves’ potential to be involved in more cattle deaths than originally anticipated.
“It became obvious there were a lot more depredations in Idaho than were being reported because people didn’t know,” he said. “They would find a dead animal and not assume it could be a wolf” causing the death.
In May 2011, endangered-species status was removed in five Western states, which in turn took over wolf management. Idaho manages them as big-game animals, similar to black bears and mountain lions, with hunting seasons.
From the 35 wolves released in Idaho in the mid-1990s, the state’s population rose to 856 in 2009 before settling to 700 or so early this year.
Online