Since the mid 1990s elk in South Central Washington around Cowlitz county have been experiencing hoof rot. These occurrences are accompanied by copper and selenium deficiencies, along with bacterial infections. More than half of the elk herds have been lost. The cases of elk with hoof rot have increased sharply since 2008, and occur in elk that are on lands that have had timer harvested from them. Many of these timber harvests are sprayed with as many as 13 different pesticides for several years after being cut. Along with hoof rot, many of these elk have deformed and misshapen antlers. After examining photos of some of these elk, Judy Hoy of Montana says that some appear to be suffering from under bites as well.

This has shown up in deer and moose as well, but appears to be more prevalent in elk,probably because of the areas they frequent.

Copper and selenium deficiencies have been seen in many declining wildlife populations across the West. These include moose in UT, bighorn sheep in WY, moose in MN, Deer at Hanford WA, black tail deer in CA, and many other cases across the West.

One of the the herbicides used on these timber harvests is Oust (Sulfometuron Methyl). Sulfometuron Methyl has been shown to produce testicular degeneration and atrophy. Sulfurometuron Methyl is a Sulfonyurea herbicide similar to Metasulfuron-methyl that has been used on the National Bison Refuge in MT and at Malhuer National Wildlife refuge in OR.

The antler deformities could be due to direct disruption of the endocrine system like the hoof rot, or it could be caused by herbicides by a secondary mode via lung worms. Red deer have been shown to develop small “cork screw” antlers when affected with high rates of lung worm. Elk with hoof rot have been seen coughing, and declining bighorn sheep through out the West have suffered from not only selenium and copper deficiencies, but lung worm induced pneumonia as well.  Glyphosate (roundup) has been shown to influence parasite loads and life cycles. This has then been shown to affect both fish and terrestrial animals. In this first case, glyphosate has been shown to affect the life cycle of snails and the parasite worms that use them for part of their life cycle. This leads to a decline in fish species affected by the increase in parasite load brought on by the glyphosate. This particular example was studied in New Zealand. We have seen a similar situation with whirling disease here in the United States, and its occurrence follows the same time frame and cycle of mule deer, bighorn sheep, elk, and moose declines. Another example of this is the way in which glyphosate influences another snail and the parasite that it carries. In this case Glyphosate increases Pseudosuccinea columella Snails, that carry Fasciola hepatica. Fasciola hepatica are liver flukes. Lung worms in ungulates are carried by an intermediate snail host that they ingest.

These hoof deformities have since been found in several locations in Oregon as well. Also in association with timber harvests.

See: Sulfonylureas