Accepted Answer

The bright colored urine may indicate he has a liver problem.
When the liver starts breaking down blood cells the bilirubin (a yellow pigment from that) starts showing up in the urine.
If his abdomen is bloated this may also indicate swelling of the liver or spleen (or both) or a leakage of fluid into the abdominal cavity.
You can check and see if your vet has any off hours contact info on their answering machine or service.
You can check here to see if there is an emergency vet in your area you don't know about
http://www.vetlocator.com/hotline.php
If your dog appears dehydrated (see if a pinch of skin over the shoulder blade stays stuck in a tent form or flows back down normally when released), has gums or tongue that look white, blue, gray or yellow tinted where they are normally pink, has a slow color refill if you press on a pink area of gum or tongue, or is becoming lethargic and non responsive to you then I'd get the dog in to see an emergency vet if one is available in your area. If there is no way to do that then you may want to be right there when your vet opens.
I would not suggest using a laxative for the dog at this time.
You can read about the med he is on here
http://www.petplace.com/drug-library/enrofloxacin-baytril/page1.aspx
but it doesn't look like a side effect from that.
The bland food and soup may help him if its just constipation from lack of moisture.
You can try giving some oatmeal or some plain canned pumpkin as the fiber in those can help a dog pass stool.
You can read about how to check for jaundice here
http://www.petplace.com/dogs/jaundice-in-dogs/page1.aspx
And it might be all this is from a prostate infection. You can see how close the anatomy all is in this diagram to see if the prostate is enlarged with infection (causing a change to the urine color) then the rectum might be blocked
http://www.vetmed.wsu.edu/ClientED/anatomy/dog_ug.aspx#lower%20urinary%20and%20genital%20tract
Hope this helps you!

Expert:	NancyH
Pos. Feedback:	99.5 %
Accepts:
Answered:	7/16/2008

Dog Expert:Rescue, Train,Breed,Care

30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics