Will Falconer, DVM Moderator
Thanks for your thoughtful comment, Eowyn. As to the cat currently facing challenges, I'd be much more focused on his clinical state (how he's feeling and acting, interacting, grooming, not vomiting, having an appetite) than I would on his BUN. That rises even in healthy, non-renal animals eating raw diets, as you likely know.
I rarely chase or push numbers. I look at how my patient is doing, first and foremost. If he was clearly failing on the raw meat diet, sure, try the vegan. Just not because his kidney values were rising.
All the best.