From googling, it looks to be a piece from a product called "Wholemeals" made by Mars who makes NB. BUT they don't make wholemeals anymore so I don't know how that would happen??
It's the only dog food I could find shaped like a bone.
Unless kibbles n bits or something like that has bone shapes?
I lied, Mars also makes something called "Small bites and bone" similar to Ole Roy and such:
http://www.petcare.mars.com/
I assume that it is made in the same plant with NB.