with what I feed my dragon?

Hi, i'm playing a knight and I just polymorphed my warhorse into a mighty silver dragon

But I am worried about one thing, do I have to give him some particular meal? I know that he could just eat corpses around... but once I had a great mastodon, that then starved under my eyes

I fear it could appen again with my dragon...

I went on playing, and saw happily that the D made out well with corpses. I tried also tripe, and it liked it.

I was so worried about him starving, when it has been me that was almost starved on sokoban (I couldn't pray, I had to eat my other pet, a white D, it got me satiated eheh)

anyhow corpses seem to keep well alive a dragon.

I did read that a carrot/apple eaten by a horse is like a food ration eaten by the player (gives same nutrition) . Is this worth also for the others pets, eating a corpse or tripe?

edit: lizard corpes? so small, how could they nourish someone? unless the lizcorpse/foodration is true, they seem useless for nutrition.