by Mark Oswald, President, Ravalli County Fish and Wildlife Association
The Ravalli County Fish and Wildlife Association (RCFWA) is genuinely concerned about the health and numbers of our bighorn sheep and mountain goats. The health and numbers of our herds determine the number of hunting permits issued, but more importantly, the survival of these herds.
Yes, we lose animals to predators, and vehicle strikes account for some. You no doubt have seen the new signs on US Highway 93 “Watch for Bighorn sheep”. Hopefully, these have prevented some vehicle mortalities (look for more signage on the Skalkaho Highway soon), but most concerning is the loss due to tiny bacteria; Mycoplasma Ovipneumonia, also referred to as M. ovi. Pasteurella and Mannheimia, are also of concern.
Bighorn sheep. Photo by John Dowd.
M. ovi and its many strains (M. ovi strains found in Skalkaho were previously unknown) have contributed to the mortalities of many of these wild animals. Domestic sheep and goats are immune to these pathogens. Bighorn sheep are NOT! The way Bighorn sheep and Mountain goats contract these pneumonias is through physical contact with domestics. A nose-to-nose touch is enough to begin an all-age die-off, partial die-off, and/or chronic lamb mortality. These die-offs can happen within a few days of contact.
Wild sheep are just that; wild and can roam. In fact, they do roam. I have photos of bighorn rams at the bridge of the Westside Cutoff taken last year. Three months ago, I spotted two bighorn ewes crossing US Highway 93, just north of Lolo. Contact with domestic sheep and goats will happen. Steps to prevent this can help (call our local FWP biologists to get advice on preventing these contacts). One local sheep and goat owner erected solid wood fencing to prevent contact from the wild sheep coming to the river fr water and then crossing to “visit” their cousins. Other methods (and less expensive) are possible to keep domestic sheep and goats separate. Seperation is the key to preventative spread of M. ovi and related pneumonia. Currently there are no vaccines.
This past year RCFWA members have witnessed small herds of domestic sheep and goats roaming (grazing) on the national forest, in the Skalkaho drainage, and in the vicinity of Laird Creek. Feral goats have been spotted in the Skalkaho drainage as well.
Last year at about this time of year, a die-off of bighorn rams occurred in the Skalkaho drainage (as reported in local newspapers). Three were collared and the others located by RCFWA volunteers and FWP employees. All were rams and died of pneumonia caused by M. ovi, probably due to contact with a goat. Why are just rams dying? Were they in a weakened state due to rutting stress? Or because they tend to roam more?
Recently, the bighorns in the Missouri Breaks have had substantial losses in numbers causing concern. Is M. ovi responsible? Sometime back about 20 years ago, a substantial number of bighorn sheep had to be culled from the Sula/East Fork herd, due to pneumonia – cause M. ovi. This was the only way to prevent the spread and preserve the remaining herd.
In your outdoor ramblings, if you see sick bighorn sheep coughing, or acting abnormal, with/without nasal discharge, or find dead sheep, please call FWP as soon as possible to notify with time, date and location so any measures necessary can be taken. Sightings of bighorn sheep in the valley floor and outside of the normal bighorn areas should also be reported to help contain outbreaks of these lethal bacterial pneumonias.