Washington Friends of Farms & Forests

We Help Washington Grow

Elk Hoof Disease

Elk hoof disease, sometimes known as elk hoof rot, has been a growing concern over the past decade, particularly in Southwestern Washington.  

What is Elk Hoof Disease?

Elk hoof disease causes lame elk because of misshapen or missing hooves.  


Test results of diseased hooves sent to five diagnostic laboratories since 2013 point to infectious treponeme bacteria, which have been linked to digital dermatitis in domestic sheep and cattle. A 16-member technical panel of veterinarians and researchers, formed by the Washington Department of Fish and Wildlife (WDFW) to review test results from affected elk, has supported those findings.

Where Are the Affected Animals?

Below is a map from the Washington State Department of Fish & Wildlife, indicating where elk with hoof disease have been reported.

Is herbicide use by timber companies a factor in elk hoof disease?

According to the Washington Department of Fish and Wildlife, there is no scientific evidence that chemicals can cause this kind of disease in animals, and no link has been made between herbicides and hoof disease in any species that we are aware of. Timber companies use similar herbicide treatments all along the West Coast, yet elk populations in other areas have not exhibited the symptoms associated with hoof disease seen in southwest Washington. 

Ongoing research with exclosures conducted on managed timber land indicates that timber management, including the use of herbicides, increases the variety of quality browse vegetation for elk and deer, and even increases the variety of bird habitat!

Generally, one or two herbicide applications are made during the first few years of a 40 year rotation cycle. Depending on the product being used, a few ounces to a few quarts of herbicide are applied per acre. The herbicide is mixed with water prior to application to ensure even coverage.


Timber is not harvested near streams or in wetlands so these areas are never sprayed. If there is surface water present at the time of an application, existing rules require a buffer zone around it.

The Cycle of Managed Timber and Impacts Wildlife Nutrition

The above cycle illustrates several points:


  • Without herbicide use, vegetation - including noxious weeds such as Scotch Broom - would take over harvested timber sites.  These species would not only out compete the trees, decreasing tree survival rate, but would also out compete native species which are more desirable browse for elk and deer to eat.
  • Thanks to suppression of undesirable vegetation, starting about the second year after harvest and until canopy closure there is excellent browse for elk and deer and even increased number and variety of bird species compared to closed canopy managed timber and old growth forests.
  • As the canopy closes, browse decreases.  By harvesting the trees (usually about 40 years after they were planted) they cycle is renewed and excellent browse for elk and deer once again becomes available.  
  • Without current timber management practices, the amount and nutritional quality of browse for elk and deer would be drastically reduced.
  • Since the amount of timber harvesting on US Forest Service land has been dramatically reduced, elk and deer now congregate on private land, where the best food sources are located.

Key Points

  • Elk hoof disease is caused by a bacteria similar to, or possibly the same as, that found in domestic livestock.
  • Herbicide use does not directly or indirectly cause elk hoof disease.
  • Herbicides are virtually non-toxic to humans and animals.  They work by affecting systems that exist in plants but not animals.
  • Timber management practices, including herbicide use, are essentially the same throughout the West Coast, yet elk hoof disease has only been found in Southwestern Washington.
  • Current timber management practices, including herbicide use, actually increases the quantity and quality of elk and deer browse, as well as bird and other wildlife habitat over the managed timber life cycle.

Additional Info on EHD