DENVER – The number of wild horses that have died at a Bureau of Land Management corral in Cañon City has increased to 106, according to the latest situation report released by the agency Saturday.
Four additional fatalities occurred Saturday at the BLM Wild Horse and Burro Corrals, located on the Colorado Department of Corrections East Canon Complex, where more than one hundred horses have died since April 23, according to the BLM.
Preliminary findings released Thursday pointed to a respiratory outbreak of H3N8 equine influenza, which the BLM says is “not uncommon” in both wild and domesticated horses, as the cause for their deaths.
All the horses that have died so far have come from a group called the “West Douglas horses” – which were rounded up in August 2021 after the Oil Springs Fire burned about 12,000 acres south of Rangely, Colo., last June.
“Post mortem examinations consistently found pneumonia characterized by severe pulmonary edema and hemorrhage,” the April 29 situation report states, adding about 40-60% of the West Douglas horses were showing signs of fever, nasal discharge and coughing, and about 20% of horses in other pens throughout the facility were showing similar symptoms.
The report, prepared by Dr. Albert Kane, with USDA APHIS Veterinary Services in Fort Collins, and Steve Leonard, the WHB State Lead for the Bureau of Land Management in Colorado, also states some West Douglas horses are “either unvaccinated, have only received one shot, or only recently received their booster shots about 10 days before the outbreak.”
Both Kane and Leonard stated in their report that in addition to voluntary quarantine of the entire facility, supportive care for affected animals and biosecurity measures have been put in place.
They warn most of the affected horses cannot be treated without use of hydraulic squeeze chute systems, which risks “further spreading the illness throughout the facility, stressing the animals that could exacerbate any current underlying issues and risk further injury to adults and young foals in the affected pens.”
For that reason, individual animal treatment will be limited, they said.
Preventive medication of water with antibiotics is being considered but has not been implemented at this time, they also wrote, adding that dust mitigation efforts, including wetting down adjacent roads and gravel areas is being done on an ongoing basis.
The bureau said in addition to working with the diagnostic lab veterinarians, it was working with others from the U.S. Department of Agriculture and the Colorado State Veterinarian’s Office to figure out and mitigate the reasons some of the horses are seeing fatal cases.
Among the recommendations issued in the report were added cleaning and disinfecting procedures for trucks and equipment and bringing in a separate loader to handle the carcasses of the dead, and further sampling for more clinical signs of disease.
BLM first reported the incident Tuesday, saying the facility was under a voluntary quarantine due to an "unknown yet highly contagious" disease outbreak.