Depends on what kind you have? I have several, a pet thermometer which is rectal only- a horse thermometer which is larger, has a ring on the end a string on it and a clip so you can attach it to the horse's tail (so you don't accidentally lose it) Basically a rectal thermometer will work. They also have the pet thermometers that go in the ear, but they are spendy-
well actually I meant would there be a differance in the reading of one verses another or a differance in the temperature, like plus or minus, I think that's what I am trying to say