Northern Rocky Mountain Timber wolves are a sub-species of the grey wolf. They were native to MT, and were wiped out between 1915 and the 1930's.
The Mackenzie Valley Grey wolf is another sub-species of grey wolf. They are NOT native to this area. They are much larger and more aggressive than the Rocky Mtn wolves that were native to this area.
The original goal of the introduction program was 10 breeding pairs in MT, ID and WY. In 2004 there were 835 wolves and 66 breeding pairs. Montana alone had a minimum estimate of over 650 wolves at the end of 2011 according to MT FWP.
"USDA Montana Wildlife Services (WS) confirmed that 74 cattle, 11 sheep, 2 dogs, and 1 horse were killed by wolves in calendar year 2011. Additional losses (both injured and dead livestock) most certainly occurred, but could not be confirmed."
http://fwp.mt.gov/fishAndWildlife/management/wolf/default.html#aboutWolves
Also from the same page
Wolves from Canada began to colonize the Glacier National Park area in 1979, and the first wolf den in the western U.S. in over 50 years was documented there in 1986. The wolf population in northwest Montana grew as a result of natural reproduction and dispersal. By the end of 1994, there were about 48 wolves in and around Glacier National Park.
In a nutshell…don't blame wolves for eating a tiny percentage of your fat, slow feedlot cattle or your girlfriends pursedog.
Furthermore, they don't deserve to be shot on sight or described as vermin. You might want to look into the studies that show that the new wolves of Yellowstone have been instrumental in the restoration of the local ecosystems.
http://www.sciencedaily.com/releases/2003/10/031029064909.htm