Alright, Alfalfa disagrees with my stomach and stinks if you burn it ('') but the rabbits like it.
Its a little too high in protein to be a staple food but its blended into rabbit pellets and when mixed with fresh greens its healthy for them.

But usually when a rabbit looses its appitite, its has indigestion or constipation, whic is preferable to wet tail, but it needs hydration and fiber to get things moving again
If the problem happens again you should give it hay or little alpha grass is ok. Rabbits are pretty intollerant of changes in their diet, but are hopeless nibblers as well (as can be obseved in the this house's tomato garden) so there is no telling what made it lose its appitite, but easily remedied

Prblem is, it can be difficult to make a rabbit drink if it doesnt want to...Gatorade is a great rehydrater and appitite stimulator for virtually all mammals. It tastes better than water and it is the only softdrink besides water and sometimes fruit juice that any pets should drink. It has just enough mineral salts to stimulate eating and a low enough fructose and sucrose content to not inhibit the salt absorption. you can instead give a rabbit a little applejuice in the water to boost energy, but over 6% sugar may upset her digestion even more. You can also buy commercial rehydration formula made for human babies or primate babies (saline solution, you may not remember but you mother probably gave it to you when you got the flu as a baby) and it has less suger, but many zoos just use gatorade universally for any mammal