Like most equines, Ruzeth has very blunt teeth, which are unlikely to harm a prey when passing into it. He has a broad tongue and produces copious saliva. His internal flesh is blue.
The stomach is like any other and digests things, and he can't bring stuff back up voluntarily. When something is being unruly, however, he can channel electricity down into them to calm them down.
Everything else proceeds as normal, through the small intestine, the large intestine, and then out.
• Mostly Prey
• Reluctant Pred
• Unwilling Prey
• Digestion
As a zebstrika, he's typically an herbavore and that makes him a target for the more predatory pokemon, especially the larger ones who can deal with his bulky form. He will put up a bit of a fight, but dragon types or other critters probably can get him down.
He's unlikely to predate himself on his own terms...though he has been known to accidentally swallow a pokeball or two due to clumbsyness. Sometimes small pokemon like ratatta can find their way to supplimenting his diet as well. Larger prey is likley the cause of an accident, or perhaps some cajoling by a third party.