Thermal cameras are great for detecting mammals, but not so good at recognizing the difference between similar mammals. Thermal sights are expensive because they are designed and built to withstand shock and recoil. You could save money by going with a handheld thermal camera, rather than a thermal weapon sight. Once you confirm the shot is safe (no other mammals behind the target) using a handheld thermal camera, you could take the shot quickly using your existing equipment.
That's what I do during nighttime live fire tests. This is the model I use for range safety.
The model you're looking at has about 1/3 the range of the FLIR because the lens focal length is shorter. The range to detect a man-size object is 450 m for the ATN 320. I'm guessing that the range to recognize a man (tell the difference between two different size and shape men) is only about 113 m. The range to recognize something about half that size (i.e., coyote vs small lamb) is about 56 m.
So, you can tell the difference between a coyote and small livestock out to about 60 yards, which is pretty short. However, you can detect the presence of large livestock out to to about 900 yds. These are very rough range estimates because range is dependent on the size of the target.