Undeveloped rumen and solid food

What happens if a very young calf with a totally or mostly undeveloped rumen eats something like an apple?

If the calf is really young, will the reflex of the esophageal groove be too strong to keep the apple from going directly to the abomasum? If this happens, the abomasum digests protein so what’s going to happen to the apple? Is it just going to pass undigested into the small intestine and cause a blockage?
If the reflex does allow the apple into the undeveloped rumen, the lack of development and gas would keep the apple from fermenting or being ruminated so will it just sit in there until it rots?
I have no trouble understanding the simple stomach but the ruminant stomach just baffles me. Please help me understand this so I can finally stop rereading this damn chapter.