You brought up really good points. I haven't researched the details of the meat supply chain, but indeed makes sense...
It looks possible to track the lot, but unless some safeguard measure is implemented (an alarm on the tracker or something?), it might be easy to change the product inside the container. A lot of tracking and alarms might be needed.

Also, another good question is what happens when the ox is divided in smaller meat pieces? all pieces will have the same blockchain number? Or they will have a piece of the ox block on its code? And how that transaction would happen?

Still wait and see what happens i guess...