Dear GrapeD Fert: While it is likely that your ferret will survive the 8-12 hour fast, it is not a good idea for any 6-year old to be stresses by a fast of that length due to the possibility of insulinoma in this age group. A fast of 2-4 hours is sufficient for both purposes; the shorter for a blood test, and the longer for surgery. When taking blood we try to avaoid a very recent meal as you may have an elevated level of sugar in the blood right after eatig, and a lot of fat in the plasma, which may throw off the readings a bit (but this can be ajusted for in many labs). We need a little more time before surgery to ensure that all food has left the stomach. The time it takes for food to pass from the stomach through the GI tract is very short in the ferret - much shorter than in the dog and cat - about 4 hours. Anything longer than 4 hours in this species is overkill, and not really good for older ferrets. With kindest regards, Bruce Williams, DVM [Posted in FML 5651]