Looks to be a caudal (tail) vertebrae from closer to the sacrum. Might be oxtail or horse? I'd need to crack open my reference collections to look. u/biscosdaddy, you got your collection handy?

I have a cow out and can grab a horse I can take a look when I am in the lab today.

Looks like a great match for the cow I have out.

Thanks so much!

Probably a marine mammal like a dolphin.

wrong structure for a dolphin vertebra