Yeah,  maybe this would not have been a very palatable option for some people (sorry for the pun - I just had to do it).

However, something like this could have been a good option.

A quick search on the internet, and it is easy to find people who raise bison.   I can't believe that someone would not have been interested in raising that calf, and possibly adding different genetics to their own herd. I'd say someone didn't look hard enough for additional options besides putting that calf down.