I am guessing it was a female American Bison but I am not entirely sure. Her horns were shorter than usual and one was broken. Was it injury or heath problem? It's hard to say.
On the photo above the bison awoke from her sleep and getting ready to take a dirt bath.
Before a dirt bath.
Bathing in dirt.
What you are going to do next? Continue taking a dirt bath or take a nap?
Generally, life is good.