Guinea Pig Passing Blood

Question
Hi I wonder if you could help.  One of my guinea pigs has been squeaking quite a lot over the last few days, when he tries to go to the toilet.

I watched him today when he started squeaking - he pooped but there was some watery looking blood on the sawdust around it, which I presume was in his urine.  Have you any idea what this could be.

Otherwise he is eating well and behaving normally.  Our other guinea pig (his brother!) is well.

Thank you for your help.

Answer
Urinary Tract Infections (UTI)

Urinary tract infections are common in guinea pigs. Their short legs put them low to the ground where they are more likely to pick up bacteria from wet bedding and droppings.

The most noticeable signs of a UTI are:
   - Blood in urine
   - Squeaking while peeing
DIFFERENTIAL DIAGNOSES
(other possible conditions)
   - Pyometra
   - Bladder stones
   - Interstitial Cystitis
  - Arthritis, spinal injury (pain peeing or passing droppings)
WHAT YOUR VET WILL DO
   - Your vet will examine your guinea pig and palpate the lower abdomen.
   - An x-ray (two views) may be taken to rule out bladder stones.
  - Your vet will collect urine or drawn it directly from the bladder using a needle.
  - If there is no visible blood, the urine can be tested for the presence of blood.
   - A urine culture can help determine which antibiotics are most effective.
TREATMENT
UTIs are generally treated with a safe and effective antibiotic like bactrim (trimethoprim sulfa) for two or more weeks. Many guinea pigs require longer treatment to clear up the infection and allow the bladder walls time to heal. Call your vet immediately if bleeding recurs after antibiotics are stopped. If your vet did not take an x-ray and the original signs you observed are still present while on antibiotics, be sure to have an x-ray taken immediately. Up
PREVENTION
Your goal is to keep your guinea pig as dry as possible to prevent infection.

   -Keeping the butt hairs of a long haired cavy trimmed may help.
   -Change bedding more frequently, especially areas that are wet (spot clean).
    -Look into polyester fabrics which reportedly allow the urine     to drain through but stay dry.
   - Some people use a safe plastic grid flooring like Envirotiles (different from wire flooring) to keep the guinea pig from direct contact with urine. Up
CRANBERRY JUICE
If your guinea pig has recurrent UTIs, try offering plain unsweetened diluted cranberry juice. Antibiotics are required to cure a UTI but cranberry juice may interfere with its development, cutting the incidence of UTIs in half.

Use only unsweetened, natural cranberry juice. Syringe feed or place in water bottle. Change bottle containing juice at least daily and preferably twice a day. Plain unsweetened cranberry juice is quite strong and bitter in taste. Dilute with water. Do not use human cranberry drinks sweetened with sugar, apple juice, or other juices.

Check your local health food stores for this product.

http://www.jackiesguineapiggies.com/handfeedingyourguineapig.html
http://en.allexperts.com/q/Guinea-Pigs-1574/medical-3.htm
http://www.oceanspray.com/products/natural_100_cranberry_juice.aspx