Urogenital problems in rabbits
If you plan to keep rabbits as pets then there are many good reasons for thinking about having them neutered. Entire male and female rabbits can become aggressive and up to 80% of females may develop cancer of the uterus if they are not neutered.
If you do decide to keep rabbits for the purpose of breeding there are many factors to consider. Rabbits breed easily (literally 'like rabbits'!) and you could potentially have many hundreds of baby rabbits to rehome in a rabbit's lifetime. The number of rabbits being born is far higher than the number of good homes available for them so think carefully as to how you would deal with the unwanted babies.
Urinary tract problems can occur in rabbits and may be due to a build up of calcium stones in the urinary tract. Most animals only absorb sufficient calcium from their diet in their gut. Rabbits however take up calcium at a rate that depends on how much there is in their food (if there is more calcium in their diet they will absorb more). If they have more calcium than they need then the unwanted portion is excreted in the urine and it may be deposited to form solid sludge or stones. If you are worried that your rabbits urine looks abnormal or that your rabbit is having trouble going to the toilet then you should contact your veterinary surgeon for advice.