Malheur National Wildlife refuge has been the site of a large number of mule deer cactus bucks for many years. This goes for mule deer on the adjacent Steens Mountain as well. Since at least 1995 at least 2 different herbicides were used experimentally for weed control on Malheur. One of these herbicides, Telar(chlorsulfuron) is known to have a high risk of reducing fertility in terrestrial animals. Another of the herbicides used was Escort(metsulfuron-methyl) metsulfuron-methyl is a sulfonylurea herbicide that is chemically very similar to  Sulfometuron methyl, and works by the same mode of action. Sulfometuron methyl has been shown to cause testicular atrophy like is seen in Hanford Washington mule deer.  These early experiments were conducted by personnel from Monsanto corporation. Spraying herbicides at Malheur continues to this day.

See: Sulfonylureas