Modern Milking machines cannot milk any animals except cows. Its almost impossible to mix milks from differnet animals
So it very well might be that there is Donkey Cheese, but you have to get it very differently than cows milk cheese. The udder sizes are different and the pipes for the cows udders will not fit any other animal.
To get Donkey milk you would need to buy a milking machine that milks donkey udders.