Identifying a lone bone found newar Rowena Crest, Oregon (USA)
My guess is that it's a relatively young cow humerus. The strongly grooved trochleas are more characteristic of a humerus than a femur, which usually just has two condyles. The deep pit is where the olecranon process (your bony elbow) goes. The proximal end is missing, which indicates that the growth plate was not fused, suggesting juvenile.

And I guess cow because cows are very common and have robust bones compared to other artiodactyls.

Here's an image pulled from the web: