Hi, I’m Claudia and my baby bunny boy, castrated, is 8 years old and has been dealing with sludge and bladder stones since he was 6. He had surgery in March 2022 to clean the bladder and since then he’s been taking the Sherwood supplements for urinary tract, he eats 1% of his body weight in pellet food which is Science Selective for Urinary support too. The only fresh green I give him now is fennel and I give him a variety of dry herbs, small amounts per day, like chickweed, plantain, nettle, chamomile, calendula, vine, rosemary, etc. Each day I choose about 3 and I keep changing each day. He always has timothy hay of high quality, not cheap and to drink more water I do a chamomile infusion each night and he’s been drinking about 150ml per day. After surgery he was still gaining sludge, so we tried liquid magnesium supplement in his water, 0.6ml in 200ml of water and apparently it worked since the sludge practically disappeared but now he has his cholesterol really high and we don’t know what could have done this. Anyway, since you’re answering questions about sludge, do I think he has a good diet and Sherwood supplement or is there something else I can do or change?
I wouldn’t worry about cholesterol levels in rabbits. They are not associated with problems. If his sludge has resolved that is great, keep doing what you are doing. Getting the rabbit to take in more fluids, orally or injectably is very helpful. It is also important that they don’t get overweight and they stay active. You need to prevent future sludge from building up. I recommend performing x-rays a few times a year to monitor for sludge recurrence.
Please check the label on the pellets you are feeding. If there is alfalfa in the pellets then I recommend switching to a Timothy based pellet.
Apparently too much vitamin c causes stones in humans. Is this also true for rabbits?
No. It is hard to overdose on vitamin C since excess amounts will get peed out. There are reports of kidney stones in humans from high doses of vitamin C, but it is uncommon. Rabbits can make their own vitamin C, so they do not require supplementation like guinea pigs and humans do. In rabbits stones can be caused by high doses of calcium in the diet, or a problem with their calcium metabolism. Stones can also occur due to infection.
One of my rabbits recently experienced urine sludge. I’ve added photos for reference. I have the following questions:
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- Is urine sludge always a sign of kidney stones?
- Can it lead to kidney failure?
- Besides water, are there any supplements, vitamins, or medication that should be given to prevent the calcium build up?
- How should diet be changed?
- When is medical attention needed?
It is normal for rabbits to have calcium crystals in their urine. Normally they will pee them out. If the rabbit is overweight, inactive, or has arthritis, they may not pee normally, and may retain urine. When they retain urine, the heavier crystals remain in the bladder instead of getting peed out. The crystals build up and become like mud- this is called sludge. Sludge can also occur if there is excessive calcium in the diet or from kidney insufficiency. Most rabbits with bladder sludge do NOT have stones in the bladder or the kidneys.
Stones are also calcium based. They can occur in the bladder or urethra. They can also occur in the kidneys, and the rabbit may pass them as kidney stones. This is painful, and can sometimes cause a permanent blockage of that kidney. Kidney stones are usually an indication of decreased kidney function. Stones in the kidneys or bladder can occur due to a bacterial infection. If there are stones in both kidneys, then the rabbit has very decreased kidney function and their kidneys will eventually fail.
There are no medications that can dissolve calcium based stones. Increased fluid intake can help to prevent the stones from getting worse. There are several supplements that have been discussed to try and decrease stone formation. Potassium citrate works to acidify the bladder in some species (acidic urine decreases calcium stone production). But it is unable to acidify the urine in rabbits. Hydrochlorothiazide is a mild diuretic that is supposed to decrease the calcium levels in the urine. Dissolve KS by Evergreen herbs seems to be helpful. I also like to recommend the urinary supplements by Oxbow and Sherwood. Magnesium has been discussed but there is no data about its effects.
For rabbits with bladder sludge or stones it is recommended to avoid alfalfa based food, kale, and parsley.
Medical attention is needed if the rabbit is painful when urinating, peeing outside the litterbox, has blood in the urine, or stops eating. Looking at your photos I would strongly recommend that your rabbit have x-rays performed.
How to deal with the GI disturbance from the education prescribed for bladder sludge and cystitis?
If the rabbit is on antibiotics for a urinary tract infection, that could cause a GI upset. It is best to avoid antibiotics that cause GI upset. It is ideal for the veterinarian to perform a urine culture to see exactly what the best antibiotic is to use. In some cases of sludge or cystitis vets may recommend Meloxicam. Most rabbits tolerate it well but a few rabbits may have a decreased appetite. Again, anything that causes a decrease in appetite should not be given.
Antibiotics and anti-inflammatories are often insufficient at treating sludge. For treatment of bladder sludge I usually recommend Sq fluids, oral fluids, make the greens watery, avoid alfalfa, kale, parsley, get the rabbit down to a normal weight, increase exercise, and treat with pain relievers if there is any arthritis. Often the rabbit will need to have the sludge flushed out of the bladder. This can be done under mild sedation using a urinary catheter.
Do greens high in calcium cause bladder stones? My rabbit loves kale but I am scared to feed it too often.
If your rabbit does not currently have stones or sludge, then a small amount of kale as part of a healthy diet will not cause problems.
Can bladder sludge/stones cause a rabbit to urinate blood?
Yes stones can cause blood in the urine. But if the rabbit is an un-spayed female then it is more likely that there is a bleeding reproductive tumor. Also, rabbit urine can appear brown, orange or rust colored. That is not blood, that is plant pigments and its normal.
My 11 year old rabbit is going in for bladder stone removal surgery at the beginning of March. Other than preliminary blood work, are there any other precautions to take before she goes in? Also, the receptionist at the vet (an exotics office) asked me to stop all food and water for my rabbit at midnight, the night before the surgery. Is this necessary for this kind of surgery?
A bunny that is 11 years old needs to have full body xrays performed. We need to check for other problems like evidence of heart disease, cancer in the chest, or kidney stones. Pre- op bloodwork will tell us if the kidney values are elevated or if the rabbit is anemic or has an infection. If the rabbit is eating well, is a normal weight and is acting normally then it has a better chance of getting through the anesthesia. The rabbit should also be on intravenous fluids while under anesthesia.
Rabbits should NEVER be fasted before surgery, do not remove food and water. We want rabbits to be eating before and after surgery. At a dog/cat/exotic hospital often the receptionists do not realize that rabbits should not be fasted, so they give out that misinformation. Please make sure that your veterinarian is experienced with performing surgery on rabbits.
What is the difference between bladder sludge and stones? Does one lead to another?
It is normal for rabbits to have calcium crystals in their urine. Normally they will pee them out. If the rabbit is overweight, inactive, or has arthritis, they may not pee normally, and may retain urine. When they retain urine, the heavier crystals remain in the bladder instead of getting peed out. The crystals build up and become like mud- this is called sludge. Sludge can also occur if there is excessive calcium in the diet or from kidney insufficiency. Most rabbits with bladder sludge do NOT also have stones in the bladder or the kidneys.
Stones are also calcium based. They can occur in the bladder or urethra. They can also occur in the kidneys, and the rabbit may pass them as kidney stones. This is painful and can sometimes cause a permanent blockage of that kidney. Kidney stones are usually an indication of decreased kidney function. Stones in the kidneys or bladder can occur due to a bacterial infection. If there are stones in both kidneys, then the rabbit has very decreased kidney function and their kidneys will eventually fail.
What is the first thing I should do when I see white/gritty pee from my rabbit?
An x-ray will tell you if there is sludge in your rabbit’s bladder. Many rabbits will pee out all the calcium crystals, and that’s why their urine appears white and gritty. This is normal. If the rabbit has sludge in the bladder on x-rays, then that is a problem.
What are the risks of untreated bladder sludge and stones?
Untreated bladder sludge or stones will build up and get larger and larger, and become painful. It can also cause irritation of the bladder wall and infection. Rabbits will get more and more sick over time if stones or sludge are not treated. Also, smaller stones can pass into the urethra and get stuck, causing a life-threatening obstruction.
Is surgery the only way to dissolve a bladder stone?
Yes, surgery is the only treatment for bladder stones, unless they are small enough to pee out. Stones are calcium based and cannot be dissolved. But there are treatments that can slow down stone formation.
Are rabbits more prone to sludge/stones as they age?
When rabbits are arthritic and less active, they can build up sludge. Most sludge cases I see are overweight rabbits.
Are there certain breeds of rabbits who are more prone to developing bladder sludge/stones?
No breed predisposition.
I have a question for Dr. Kanfer regarding bunnies molting and getting bald patches. Recently my bunny was molting and suddenly I saw a bald patch on his behind. It was pretty red and I took him to the exotic vet near me who suggested it was due to molting. We grabbed a sample of the skin to look under a microscope and it was negative for fungal infection etc. I was given some antiseptic wipes to use and make sure the wound doesn’t change. A week later, the same patch looks dark purple and the skin is scabby. The bunny is eating fine and active and not scratching or biting the scab. My question is- is this bald patch during molting normal? Is the skin color changing to purple and getting hard/scabby normal? And will hair grow back? I couldn’t find anything about this online so I was curious if Dr. Kanfer can shed some light on this.
Rabbits do not usually get a bald patch when shedding, unless they were overgroomed. Fur mites may be present and not show up on a microscopic exam. If the rabbit has a lot of dandruff that is usually a sign of fur mites. Is the skin truly scabby or does it just look dark? If it looks dark then most likely the hair follicles are regrowing. If the skin is scabby and purple, that could be a serious wound. Improper grooming could cause a skin wound if the skin was torn or cut with a scissor.