Possible UTI?

I have a neutered buck about 2 years old. He is eating, drinking, peeing and pooping as normal. We have a vet appointment for Saturday and will certainly go sooner if needed. Currently, he seems fine other than he is getting soaked with urine at times on the top of his tail right at the base. I noticed it by accident when he laid down and extended his tail in the process. If his tail is up you cannot see the urine on his tail. He is getting some on the bottom of his tail at the base, but mostly on top at the base. He is drinking a fair amount. He is paying a bit of attention to his back end, but not much. There is a slight odor from the litterbox like there was when my other bun had a UTI, but it is not as noticable as it was last time, but it is the same smell. I am keeping him as clean as possible with a damp cloth and combing cornstarch into the fur to try to keep him dry. Sometimes he is fairly wet, but most of the time just damp. I am also keeping a close eye for urine scald.

Anyone have any ideas on what might cause him to get urine on top of his tail? I am leaning towards UTI, but have also thought stones possibly, thinking if one is partially lodged in there it might cause his urine stream to go in weird directions. Like I say, he seems totally fine otherwise. He is having accidents outside of the cage, but minimally inside the cage. We do have extra dogs in the house since Wednesday, so this is likely related to that, although both buns are quite familiar with the two dogs. More marking going on, however, by the buns.

Has anyone seen this before?

A UTI is certainly a possibility. Bladder sludge/stones are also another common cause. Other less common things that can cause incontinence are arthritis(usually with older buns) and the parasite e. cuniculi.
http://www.bio.miami.edu/hare/urinary.html

The urine on top of the tail may be from the urine dribbling out and leaking down his bottom to his tail when he's squatting. He would be able to reach the bottom part of his tail to clean the urine off his fur, but wouldn't be able to reach the top for cleaning, so that may be why you are finding most of the urine soaked fur there. Only other thing I can think would cause it to get there is if he is spraying to mark, but this would be very uncommon for a neutered buck.

You will also want to keep a really close eye out for flystrike, and check your bun several times a day and try and keep him as dry as possible. I think this is one of the greatest risks involved for rabbits with soiled bottoms in warm weather, and it can occur in a matter of hours.

Best of luck at the vets and hopefully they can determine the cause with out too much trouble.

I am definitely keeping an eye out for fly strike. He is inside, so that reduces the risk, but is definitely something to watch for. He's never sprayed as long as I have had him, and I ruled out sludge since his urine seems totally normal. I guess I will just have to wait and see what the vet comes up with and keep him dry and clean between now and then. He was totally dry this morning, so at least he is not constantly wet. Thanks!