Rabbit's urine can range anywhere from a milky color, to clear, to a bright reddish/orange color. It's normal.
The milky color can indicate an excess of calcium in their system, orit could just be the difference in the way their body is processing andbalancing what it's eating.
It's best to keep the calcium levels under 1% in their food if you'reseeing a lot of this. Some greens, such as kale and parsley, have ahigh level of calcium in them. If you're giving your little one that,you might cut back some. Also, alfalfa hay or based pellets are knownto be high in calcium. Consider switching over to grass hay or timothyhay.
If the substance is white and thick, like toothpaste, that could be anindication of her passing sludge, which she'll do and get over. There'snot a lot you can do for that either other than go with the grasshay/timothy hay, and go to a lower percentage of calcium in the foodyou're currently giving.
-Carolyn