Transient changes in the appearance of her urine are usually not significant. If you see changes that persist over 2-3 days, if the frequency of urination seems to be increasing or if her attitude or appetite are affected then you should let me or your vet know. The color or colors of urine as well as its concentration and smell are determined in large part by the nature of food or other things ingested, as well as her water balance so there are normal changes in appearance that occur from time to time.