Does Your Rabbit Have White Urine? Don’t Panic! It’s Probably Normal

Have you looked into your rabbit’s litter box lately and noticed something that looks like white urine? You’d think that can’t possibly be normal, but it actually is. It’s just not technically urine, instead it’s excess calcium.

Rabbits have a unique way of dealing with calcium in their diet. Thet absorb calcium at a constant high rate and filter out the excess through kidneys. It leads to the presence of excess calcium carbonate, which has a milky white appearance when it’s excreted.

That being said, you do want to be familiar with the difference between normal calcium excretion and bladder sludge, since the two can look similar. Bladder sludge is when a rabbit excretes a thick paste when they urinate. It’s related to kidney stones and is a sign that some underlying health problems need to be addressed.

So, even though calcium deposits are normal, you’ll want to be able to differentiate it from bladder sludge and bring your rabbit to the vet if you notice the latter.

• Learn more about how to know if your rabbit’s urine is healthy

What is the white “urine?”

That white substance that looks like pee in your rabbit’s enclosure is not urine in the typical sense, but rather calcium deposits. Rabbits metabolize calcium differently than humans and most other mammals. This is due to a unique characteristic of their digestive system which absorbs all the calcium from their diet and excretes anything they don’t need through the kidneys and urinary tract.

Seeing this white “urine” (it’s actually just a form of calcium) is completely normal to see on occasion, especially in rabbits who have a diet with a higher calcium content. 

Young rabbits, for example, are typically on alfalfa-based diets which have a higher calcium content than the timothy hay given to adult rabbits. This is why it’s much more common to see this white ‘urine’ with younger rabbits.

Do frequent calcium deposits mean you should change your rabbit’s diet?

So here’s the next question that I’m sure many of you are wondering, what if your rabbit has a lot of white ‘urine?’ Does it mean that there is too much calcium in your rabbit’s diet?

Frequent white deposits in young rabbits is quite common since they have alfalfa hay in their diet, which has a higher calcium content than timothy hay. Since they are still growing, young rabbits (less than 1 year) need a lot of calcium to keep their bones healthy.

Unfortunately, there is not a clear-cut answer. From the research I’ve done, it seems that there is still a lot we still don’t understand about how this calcium excretion works in rabbits.

Some research suggests that excess calcium can lead to bladder sludge and kidney stones in rabbits, as the calcium sediment builds up in their kidneys. However, in other rabbits they seem to be unrelated or even have the opposite relationship. Others have suggested that it seems to be a lot more based on hereditary and genetics; some rabbits are simply better at processing calcium.

As someone who is not a veterinarian, I do not feel comfortable giving specific advice on this issue. If you are concerned about the amount of calcium your rabbit is excreting (or if you think it might be bladder sludge), I recommend talking to a veterinarian who is familiar with rabbit anatomy. Your vet may recommend that you switch to a different brand of rabbit pellets, or offer your rabbit less calcium-heavy leafy greens.

Bladder Sludge vs. Calcium Deposits

Bladder sludge is a thick paste that your rabbit urinates, it is usually a slight gray color, rather than being fully white, and it is excreted as the rabbit urinates (the calcium deposits are usually separate from typical urinating). When dried, it will have a rough, gray, chalky residue and may even have the consistency of sand.

There will always be a small amount of sediment in a rabbit’s urine, however there should not be a thick paste. That’s an indication that something is not working correctly and your rabbit is at risk for kidney stones or might have a urinary tract infection.

Other symptoms of bladder sludge include:

• Straining to urinate (this may look like they are straining to poop, but it’s almost always straining to urinate instead)
• Incontinence or urinating in places they do not normally (as if they don’t have time to get back to their litter box)
• Frequent urination (your rabbit keeps going back to the litter box to pee a little bit at a time)
• Urine scald (when urine causes inflammation on the skin surrounding their buttocks)
• Decreased appetite and energy

If you notice any of these symptoms, consider temporarily replacing your rabbit’s litter with some paper lining the bottom of the litter tray. This will help you to see more clearly if there is a thick paste or bladder sludge when they urinate. Of course, I also recommend contacting your rabbit’s vet as soon as possible as well.

Sources:

1. Claire Speight, MBVNA. “Urolithiasis (Urinary Sludge and Stones).” Rabbit Welfare Association. https://rabbitwelfare.co.uk/urolithiasis-urinary-sludge-and-stones/ 
2. Kathleen Wilsbach. “Lowering Blood Calcium.” Rabbit.org Foundation. https://rabbit.org/health/lowering-blood-calcium/
3. “Normal urine and “sludge” in rabbits.” MediRabbit. http://www.medirabbit.com/EN/Uro_gen_diseases/generalities/Sludge.htm
4. Susan Brown, DVM. “Bladder Stones and Sludge in Rabbits.” VeterinaryPartner. November 6, 2006. https://veterinarypartner.vin.com/default.aspx?pid=19239&id=6048312