From my experience the vet owns the x-rays. It is like for most
photographers where they own the negatives.

--
Larry

That's really odd. I've taken x-rays of my own out of the doctor's office to
take to specialists and they just give them to me.
Besides, the vet is not going to need them.
Old x-rays are sometimes recycled for silver content, but that would be a
pretty petty reason to want them back. Other than that, it sounds like a power
struggle on the part of the vet's office. I am horrified that no expression of
sympathy was made to the OP by the vet.
Sherry