bullets

Hello, I'm new here and know nothing about detecting. I would like some advice about detecting a bullet in a dead cow. I am a farmer and want to rule out this possibility with two dead cows I have had lately. It's below 0 here with lots of snow and a day or two going by before things are seen so a bullet lodged in a cow would not necessarily be bleeding or even noticeable until some infection occurs. This isn't simple. Advice please. Thankyou. Mark