Bladder Sludge in Rabbits and Guinea Pigs

Bladder Sludge in Rabbits and Guinea Pigs

Bladder sludge is a fairly common problem seen in both rabbits and guinea pigs. It occurs when excess calcium in the diet or poor bladder emptying leads to thick, chalky urine filled with crystals. Over time, this can irritate the bladder wall, cause pain, and increase the risk of infections or bladder stones.

What is Bladder Sludge? 

  • Normal urine in rabbits and guinea pigs can sometimes look cloudy due to calcium, but healthy animals are usually able to excrete it without issue.

  • With bladder sludge, the urine becomes thick and gritty — like toothpaste — and sits in the bladder instead of being passed easily.

  • This irritates the bladder lining and can progress to urinary tract infections or bladder stones if untreated.

Signs of Bladder Sludge

You may notice your rabbit or guinea pig:

    • Passing thick, white, or gritty urine

    • Straining to urinate or making unusual postures when toileting

    • Wet or dirty fur around the back end

    • Blood-tinged urine

    • Reduced appetite or reluctance to move

    • Signs of pain such as teeth grinding, hunched posture, or hiding

If you see any of these signs, it is time to book a Vet check! 

What Causes Bladder Sludge?

Several factors can contribute:

  • High-calcium diets (e.g. too many alfalfa-based pellets, lucerne hay, or calcium-rich vegetables)

  • Poor water intake (not drinking enough means urine is more concentrated)

  • Lack of exercise (reduced movement can make bladder emptying less efficient)

  • Genetics and individual variation (some pets are more prone than others)

  • Underlying illness reducing bladder function

How to Help Prevent Bladder Sludge

    • Feeding the right diet:

      Base diet on grass hays (like timothy, oaten, meadow, or ryegrass) rather than alfalfa/lucerne.

Offer a variety of low-calcium vegetables (e.g. capsicum, herbs, cucumber, lettuce, carrots in moderation).

Limit high-calcium greens (e.g. kale, spinach, parsley).

Use pellets sparingly — and choose adult formulations, not alfalfa-based.

    • Encouraging hydration:

Provide fresh water at all times, ideally in a bowl (many drink more this way than from bottles).

Offer water-rich vegetables (like cucumber or celery) to boost intake.

    • Promoting exercise:

Give plenty of space and enrichment to encourage movement.

Time outside the hutch/cage helps with bladder emptying.

    • Maintaining hygiene:

Keep housing clean and dry to reduce infection risk.

What will we do here at The Wild Vet? 

At the clinic, we may recommend:

  • Physical exam and review of diet/husbandry

  • X-rays or ultrasound to check for sludge or stones

  • Urine testing to rule out infection

  • Fluid therapy, pain relief, and medications if needed

  • Surgical intervention in severe cases of bladder stones

Contact us today

Bladder sludge is common but preventable in rabbits and guinea pigs. The right diet, hydration, and exercise can greatly reduce risk. If your pet shows signs of urinary issues, early vet care is essential for comfort and long-term health.

 Click here to Book a rabbit or guinea pig health check,  or if you have any questions, give us a call on 1300 WILD VET (1300 945 383)