Eat it sure. Can they survive on it? Cats have to turn their heads to eat grass because they don't have flat incisors like horses or cows. Their canines get in the way. They don't have flat molars either, so grinding grass up is extremely difficult. Every time my cat puked up grass the blades were practically whole. All not good for an ostensible herbivore.
Find me the skeleton of a cat with a ruminant's dentition and you'll convince me. Otherwise, that's a mighty transformation to pack into the Fall. I think it's just easier to limit the effect of the Fall to human death rather than animal death.
Well, He’s got a plan. Could be veggies. Our old english shepherd loved eating the green beans off the vine, too. They like pears. I don’t know, yet. It’s fun to think about though. I wonder if fish are included.
I’m sure it would be mere child’s play for the One True God who wrote the billions upon billions of lines of DNA code to re-write it once again [or once before?] or even just do a reset to the initial good or perfect conditions He declared on the 7th day of creation.
Who are we, mere puny humans, to argue with the Almighty God or declare anything impossible/improbable?!?!