I would take care of business with a knife, drag the animal to the side and ask her if she was ok and go on my way.

We had a situation quite a few years back where as some fellow hit 6 cows on the road as we were going deer hunting. My uncle ended up shooting all 6 cows and the officer had thanked us for it. He said he would have had to write a report with lots of paper work and said this was the simplest way.