Elk Hoof Disease: Lots of Data, Few Answers, for Now

A renewed interest in studying elk hoof rot got a true kickoff on Monday as the Washington Department of Fish and Wildlife’s public working group for the disease met in Ridgefield for the first time in nearly two years, the meeting was spurred in part by funding from the state Legislature this past session.

State and university officials, regional wildlife advocates and private citizens apart from the working group sat down at the brand new Washington Department of Fish and Wildlife Region 5 headquarters in Ridgefield where several members of the public voiced concerns over actions regarding the disease.

The meeting served as a review for the working group, which had last met in December 2015, and the data gathered in that time and before regarding local elk populations and the effect of hoof disease on them.

The research was done specifically looking at treponeme-association hoof disease (TAHD), a type of digital dermatitis (hoof infection) caused by a specific type of bacteria. The hallmark “hoof rot” found in local elk populations causes deformities in the hoof, in some stages causing a claw-like appearance. In advanced stages, the disease can leave the afflicted animal with a stump where the hoof would be.

Although the core focus area of the WDFW’s research was in the Cowlitz River Basin where the disease was first reported sporadically in the 1990s, the disease has been found throughout Western Washington, meriting a future change in the working group’s scope, WFDW Region 5 Wildlife Program Manager Sandra Jonker explained.

Outside of that area, Jonker said there were confirmed positive hoof disease cases in Skagit, Mason, Thurston and Whatcom counties in 2016 alone.

The group met following the passage of Senate Bill 5474, which among other stipulations to benefit the elk population charges Washington State University with being a lead for an elk monitoring project. The bill passed through both chambers of the Legislature unanimously. The legislation appropriated $1.5 million to the project.

Specifically, the bill names WSU as the lead “in developing a program to monitor and assess causes of and potential solutions for elk hoof disease,” according to the session law document.

As to why the WDFW is involved, it came down to jurisdiction. The department has authority over the elk population in the state, WDFW Game Division Manager Anis Aoude explained. Thus, both agencies need to work together for the Legislature’s charge to be fulfilled.

WSU College of Veterinary Medicine Information Officer Charlie Powell spoke from the university’s perspective of the project, mentioning that laboratory space for it had already been identified. The institution was in the process of finalizing a job description for the lead research on the project, with advertising for the position hopefully concluding in November before interviews can be held and a candidate can finally be chosen.

The Data

District wildlife biologist Brock Hoenes reviewed some of the ways WDFW has been collecting data on the disease in the past few years. He spoke about the challenge of quantifying how many elk in the population are affected by the disease, something he said is “a very difficult thing to do.”

The department had implemented four primary tools for data collection over the years. Since establishing the option in 2012, online reporting resulted in data on a little more than 1,000 elk, though reports have been in decline. Hoenes said a likely cause could be response fatigue, as hunters reporting year-over-year on the same area may stop if they feel no reason to continue.

One of the work group members, Wahkiakum County Commissioner Daniel Cothern, was more in favor of another answer.

“I can answer some of that; the elk aren’t there, so you have nothing there to observe, and that’s really the issue” Cothern said. He remarked that the elk population in his county is “decimated” likely due to hoof disease.

He questioned what hit the Wahkiakum County populations so hard when populationsfurther to the west and close to the coast populations seemed to be thriving in comparison. He didn’t notice any difference in wildlife management that might be behind the discrepancy.

The department in spring 2015 formed a citizen science effort where volunteers were asked to report what they observed out in the elk habitat. About 223 volunteers observed 283 groups of elk, and from the raw data, 6 to 8 percent of the elk were limping, one of the major indicators of the disease. Upon correcting for reporting errors, Hoenes said that close to half of all groups observed had at least one limping animal.

Aerial surveys observed a comparable amount of groups to the citizen scientists with similar results. Of the groups observed, 42 percent had at least one and 23 percent had at least two limping animals based on the raw data, Hoenes said. 

In the fall of 2016, hunters who successfully harvested an elk in Western Washington were asked whether any animals they harvested had, in their opinion, deformed hooves. Of 2,500 respondents, 15 percent said that they did have an animal with deformed hooves, with those specifically in Southwest Washington having a slightly higher rate of 19 percent.

The next logical question, Hoenes said, was determining how many of the cases were actually hoof disease and not some other ailment. Roughly 500 permit holders were asked to provide hoof samples, which resulted in 52 complete samples being sent to the department.

A little under half of the samples were determined to have the disease, though there were significant discrepancies in reporting, Hoenes said. For the samples, there was a false positive in 4 percent of the cases, though there was also a false negative rate of 48 percent. 

Hoenes said those false negatives were likely due to the nature of the early stages of the disease, which can be harder to detect and are far less obvious than those when part or all of the hoof is missing.

The department also conducted a survival study on more than 100 elk in five game management units (GMUs) in the core area of the Mount St. Helens herd, the herd where the disease first occurred.

Of the 82 elk monitored that had TAHD, the disease was involved in rear hooves in every case, involving just one back leg in three-fourths of the cases. In 12 percent of the cases, the front hooves were diseased.

For all that data collection, Hoenes did not think any one of them was showing true prevalence because of the limitations inherent in the type of reporting.

Testimony

Cothern was not the only member of the working group with firsthand experience of population decline likely due to hoof disease. One of the working group members, Mark Smith, spoke from his own experience in 20 years on his Eco Park Resort property in Toutle, on the effect the decline was having. By his estimate, there were 120 elk on average on his 80-acre property for about 14 of those years.

“Today, it’s at zero. I see no elk from May all the way through to November,” Smith said. He acknowledged that other factors could come into play, but his estimates were that the populations on his property were about 75 percent affected.

“I myself have witnessed 38 dead elk with hoof disease in the last two years in and around the area,” Smith said.

Members of the public gave testimony on their own concerns, including both proponents and opponents of the idea that the use of herbicides in forestry was a cause of the disease. The WDFW’s official stance, as per their web page on the disease’s cause, states that “there is no scientific evidence that herbicides, such as those used by timber companies, cause this disease, and no link has been made between herbicides and hoof disease in any species that we are aware of.”

Some of the public were not so sure. Gene Crocker, a former Toutle postmaster who “spent 68 years in the woods of Cowlitz County,” testified that when foresters started to use herbicides, populations began to decline.

“We’ve got to stop this spray,” Crocker said. “I’m sure it has to do with hoof rot.”

Bruce Barnes, an avid elk hunter and “a person that spent a lot of time on this (SB) 5474 bill,” expressed appreciation that work appeared to be moving, but complained that the rate at which research has been conducted was slow in the eyes of the public.

“My biggest concern is if we took this long on ebola, we’d all already be dead,” Barnes remarked. 

Barnes said the previous weekend at Mount St. Helens he saw only four elk in about 60 miles of coverage on bike and on foot. He said that long seasons, erroneous counts and over-harvesting were leading to the state offering “a poor product” to its permit-paying citizens.

“My hope is that by doing this bill Washington State University is going to take a real objective look at what’s going on here. I mean a real objective look,” Barnes said.

Although to the public the progress might seem slow, the officials said the kind of research needed would take time, and the current momentum is encouraging.

“I’ve been at WSU in the College of Veterinary Medicine for 27 years now. I’ve only seen one other project move faster,” Powell remarked. “That’s when we had mad cow disease in this state in 2003.”