Dealing with Calcium Issues in Guinea Pigs

twin rexImage courtesy of Karine Jans

Karine's twin Rex guinea pigs.

As many among us, I have had calcium issues in piggies and it was a long sad road till we discovered what to do about it. I will tell you the story and the resulting solution, which can help many more pigs with similar problems.

One of my piggies died because her heart was getting too weak to pump blood through the kidneys and the kidneys had to make too much effort to filter pee, so she got severe bladder grit. It got flushed and she died a few days after, because her heart was too weak. Had the vet checked her heart as I asked them to, they would have seen that the flushing was useless, but they didn’t. She was doomed anyway, there are no heart meds here available for piggies in Belgium anyway, when we noticed that her heart was failing and she was near death. We realised we needed a better vet, but that was the best vet practice we could find in the entire country.

Woozy and Whoopy were my twin Rex piggies. They had Urinary Tract Infections on and off, Whoopy had them more severe than Woozy. I kept them relatively UTI free using the necessary precautions: I have extra absorbent fleece pads under their hideys, which get flipped after a day and washed the day after, on a hot cycle with a dollop of disinfectant added to the washing detergent. That’s how the cage liners are washed here too. I weigh them weekly, so that the slightest indication of them feeling ill would show up. Granted, don’t panic over 30g less, as that’s about the weight of one pee less in an adult pig.

I had the pigs on a 0.6% calcium diet, out of precaution. I never fed large amounts of calcium rich vegs to pigs over 6 months old. They need calcium till then, so their bones can grow well, but after that age, any excess is too much. Still, that low calcium diet wasn’t strict enough, apparently.

I put them on cranberry, as that makes the pee more acidic, which holds back bacteria growth in the bladder. I also put them on Chanca Piedra tea, about 1 cc per pig daily, to prevent bladder and kidney stone formation, because the twins both had gritty pee, a prelude to bladder and stones isssues. The pigs loved that tea, they all wanted some daily. After having the tea for 2 months at home, it seemed to “age” in the tea bags and that made the pigs farty. You bet you raise a few eyebrows when you hear a hootin’ tootin’ concerto coming from the pigs cage! I was just looking into Shininton as a replacement, when Whoopy was struck with new issues after being healed from her recent UTI.

We woke up and heard her whine, she refused to eat too. We took her to the vet, who took an x-ray after a lot of nagging from my part to do so. The vet said a huge stone was in her bladder and it would come out on its own. I knew that was impossible and I also doubted the stone, as it didn’t look like one to me. One of my best friends got me an appointment at the University Clinic of Exotic Pets in Utrecht, 3 hours from here, the best place to go to in the entire Dutch area.

So, the next day, we drove to them. My hunch was correct, there was no bladder stone, but a large blood clot in the bladder. There was a small stone and it got lodged in the urethra, the canal from the bladder to outside. There were calcium deposits in the kidneys and the ureters, the canals from the kidneys to the bladder. They successfully removed the bladder stone and blood clot, Whoopy was set to recovery. Yet, 2 days later, urine tests showed she had kidney failure, which was the basis of her issues. This meant that she couldn’t be saved to start with, but that can’t show when a stone gets blocked, as then the urine tests show the same result as kidney failure. Only further deterioration in the tests made it clear that the kidneys were bad. We lost our sweet girl two days after surgery.

Her death wasn’t in vain. The university vet gave us tips, which can help pigs, including Woozy, who has the same genetic kidney issue as her twin sister. It will extend her life drastically and make it better too. The university vet explained that piggies absorb 50% of all calcium in their food, which is a lot more than humans do. Despite that they are genetically close to humans, that’s one of differences between us and them, besides the different appearance.

He said that the cranberry and the herbal remedies were addressing the problem, not the cause. He was right, of course. The vet said to keep the entire diet to a 0.3% level of calcium. Anything high above is not tolerated, not even as a mini piece of treat, ever.

This meant I had to switch t Timothy hay, which is kinda hard to find here in the Dutch area. Luckily, some online stores sell it.

I had to try a pellet-less diet, but that didn’t succeed. Although I reduced it slowly, it was too hard on the bowels in my pigs apparently. Besides that, I was worried about the lack of vitamins, minerals and some proteins that the pigs need, especially vitamin C. Fresh veggies daily should be sufficient for vitamin C daily, but the quality level of our local vegetables worry me and I can’t guarantee that they would suffice. I got a tip on 0.4% calcium pellets, which I use now. That’s acceptable, especially because I mix them with dried veggies and herbs which contain 0.3% calcium or less.

It took some research to see which veggies and fruit contained 0.3% calcium or less, so I made a new shopping list. I have a sunlight bulb, which goes on 20 minutes a day. That’s the maximum, as it helps to form vitamin D in the skin, which also helps to absorb more calcium. Despite that the pigs need some direct sunlight daily, 20 minutes is enough regarding calcium issues.

I have kept the pigs on a strict low calcium diet and it works. I have seen a drastic change in Woozy. She was sweet, but she was my grumpy pig. She loved her sister to bits and her loss didn’t cause any dominance issues, as she was boss over Whoopy. The cage we have is humongous, it’s not that she was relieved to gain extra space anyway. After grieving for her sisters loss, she became a changed pig. She is happy, cheerful, popcorns at least daily, does zoomies, all things I never saw before, so I can only blame the new diet. She obviously feels better because of it.

I will always stick to this diet, so future pigs will benefit from it, as we can’t ever guess who will have issues with calcium or not.

Editor’s Note: Information on Guinea Pig Today should not be put in place of qualified veterinary care. Calcium issues in guinea pigs are complex, there are still many unknowns, and treatments vary across the world due to environment, food production, and genetics. If you feel your guinea pig has issues due to calcium intake, please consult your veterinarian before changing their diet.

If you have a great idea for an article about guinea pigs, please let us know. Guinea Pig Today is a network of guinea pig lovers and we’re always looking for the next great story. View our submissions page for more information on how to submit your idea.

Karine Jans

KJ was born in 1964, being female and Dutch. She's a chemist, IT specialist and a teacher. She did all of those jobs, combined those interest fields as a manager, until 2006, when she became disabled due to having MS. Having that much free time, she devoted most of it to her guinea pigs, making comics about them and writing books.

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23 Responses to “Dealing with Calcium Issues in Guinea Pigs”
  1. Patricia Horan says:

    Loved the article, but it’s frustrating not to know which vegetables and fruits the writer found to be low in calcium! All that research, shouldn’t it be shared with us? Thanks from Houdini, Crazybaby, Twyla, Muttonchops and Frito. And Patricia.

    • Karine Jans says:

      Low calcium vegs and fruits (feed fruit as treat only):
      Sweet Potato
      Green Beans
      Lettuce types (no iceberg)
      Carrots (feed moderate, can cause liver issues)
      Endive, Belgian
      Raisins (seedless)
      Bell peppers
      Melon all types
      Corn, White and the pale husk leaves.

      Hope this helps!

  2. Karine Jans says:

    I also have to add that checking tap water for calcium values is often forgotten. I have a main water tap electromagnetic decalcifier and I get the remaining calcium out with a Brita filter for the pigs.

  3. Excellent article, and what an adorable picture of the two piggies! Such cute little faces.

    I am also very interested in reading more about the low calcium diet. Perhaps the author would be willing to share a few sample meal plans, and/or a list of approved fruits and vegetables? That would be a great follow up article!

  4. It’s a great artoicle and thank you for sharing. Sorry about your girl.
    The trouble with the list is that as you say feed fruit as a treat only, it ends up as:
    Sweet Potato
    Green Beans
    Lettuce types (no iceberg)
    Carrots (feed moderate, can cause liver issues)
    Endive, Belgian

    My boys wont eat sweet potato, parsnips, squash, turnip, asparagus, pumpkin or endive. And the rest dont grow all year round. So, we just have to do what we can. The Ratewatchers Diet gives a little more balance to the menu with more available vegetables, but you may have to dig online to find it. I’d echo the need to filter hardwater too.

    • Karine Jans says:

      The idea of Ratewatchers is that the calcium-phosphorus ratio is balanced. That’s another issue and one I used until this happened to our pigs. That diet contains veggies with a high calcium level too. The way I used to do it was to give very few amounts of calcium high vegs in the past

      I count tomato and bell peppers as a vegs, although technically they are not. Endive is not Belgian endive. One is higher in calcium and the Belgium one is the only one that is OK on a low calcium diet.

      I know the amount of veggies are the limited in a low calcium level. The comment of the university vet department was that in the wild, they just eat very limited choices too, so guilt in that regard is uncalled for. Ours too don’t eat everything on that small list, plus everything is not available here either all year and some items are too expensive. It was a bit of a shock to get used to the new diet, for us, as humans. Turns out that the pigs don’t mind the difference in choice at all.

  5. Cassandra says:

    Thanks for the great article! This is a complicated issue that I am still trying to figure out.

    I’ve found that for some reason romaine lettuce gives my guinea pigs sludgy urine… I’ve talked to a few guinea pig gurus about this, but so far nothing has been found that explains why this is. For now, we just avoid it at our house!

    A moderator on Guinea Pig Cages Forum told me that Oxbow pellets may have something to do with stones: “It’s not that Oxbow has more calcium, it’s that it’s a different calcium compound, and that may be contributing to more stone formation. But it’s a complex issue, and has to do with the whole diet, including salt and other minerals, as well as the pig’s own metabolism. But there are quite a few people now who have noticed fewer problems with sludge and stones after taking their pigs off Oxbow, so you might want to try some [KM’s Hayloft].”

    Just wanted to share!

    • Karine Jans says:


      Oxbow cavy cuisine has a level of 0.35 – 0.85% calcium. The upper level is way too high.

      That was a good question about the romaine and I had to think hard. I love a challenge, lol, so thanks! Luckily I’m also a chemist, so I have an idea what happens. But I might be wrong, of course.

      Romaine lettuce should only have a calcium level less than 0.4%, which is great, so the vegs itself it not the culprit. Farmers spray a lot of sulfuric salts on the land, I know first hand coming from a farmer’s family. They have to be careful with lettuces, as they easily “burn” them, meaning those compounds take the water out of the vegs. The main idea is to make the vegs take in more water with those compounds, so the harvest weighs more, hence more profit. Romaine is a sturdier type of lettuce, so they probably get enough chemicals.

      Now here it gets complicated, so I will try and explain as well as possible. Once in the body, the sulfuric compounds dissolve into two parts: the sulfuric one and the salty one. They sulfuric help to make us gassy, humans too, not only the veg itself does that. It forms a new compound which can be farted out, together with the other gasses that are produced. The salty compound will be going back out of the body in the kidneys. In order to do that, it needs to bond again with another chemical, as most of the sulfur is gone. The best available one is calcium, so it forms the white compound that you see in gritty pee. The fact that romaine contains a lot of water, compared to some other vegs, means that there will probably be enough chemials in it to make a visible result, as all that water with chemicals needs to be peed out. Hope this makes sense.

      I don’t feed romaine myself anymore. It makes the pigs so farty, it could cause bloat. I don’t mind a tootin’ pig, lol, but I had several cases of mushy poos, until I realized it was the romaine that did it. I have several friends with the same issue who stopped giving romaine because of it too.

      Hope this helps!

  6. Chana Meddin says:

    Here at our Sanctuary, we took in a four-year-old little love, half the size of an adult, whose bones were already so de-calcified (due, probably, to starvation) that all he had holding him together was some kind of mottled calcified substance where his bone marrow should have been and only paper-thin We Don’t Know What holding it together until, finally, after noticing his lethargy and pain chewing, I took him in for new x-rays and to the astonishment of both the vet and I, parts of his skeleton were actually MISSING (his jaw) appearing only on the films as BLACK NOTHING where a skeleton should have been. She saw so much decalcification or whatever he had (as his X-rays were that unusual, even to the person who the vet sent them to for a consulation) that she also sadly informed me his condition was indescribably painful although I never heard him moan once. He was “my baby” and often slept with me while I stroked and petted him because I have never had a piggie talk, chew, and eat in his sleep. We recently lost him and the hole his loss leaves feels like the black hole on his x-ray. As a Sanctuary/Hospice, we know ahead of time that heartbreak awaits us but two vets and two different experts who read his X-Rays were both astonished at what they saw. Basically, he “didn’t have a bone in his body!” And, of course, despite this, was the most forgiving, the most eager to love and be loved.
    Has anyone else ever experienced a guinea pig with no “bones” before? Thank you for this article, calcium is not much spoken of, mainly Vitamin C deficiency.

    • Karine Jans says:

      There are a few conditions, which both exist in piggies and in humans, which cause birth defects, so they are born without a jaw: Otocephaly, Pierre Robin Syndrome and Aplasia of the mandibular condyle. They are extremely rare, but can happen and can be lethal.

      I’m so sorry about the little one! There is also a disease called Osteodystrophy which decalcifies bones in piggies, mainly in Satins. Hope this helps.

  7. Karine Jans says:

    There are a few conditions, which both exist in piggies and in humans, which cause birth defects, so they are born without a jaw: Otocephaly, Pierre Robin Syndrome and Aplasia of the mandibular condyle. They are extremely rare, but can happen and can be lethal.

    I’m so sorry about the little one! There is also a disease called Osteodystrophy which decalcifies bones in piggies, mainly in Satins. Hope this helps.

  8. Karine Jans says:

    We are now a year later since the diet changed to low calcium, as described above. It works like a charm!

  9. daphne says:

    What pellets do you use? I’m also from the netherlands. You said: ” I got a tip on 0.4% calcium pellets, which I use now.”
    I’d like to know, please!
    Thank you for the article! My guinea pig has a problem with blatter stones because of calcium.

  10. Karine Jans says:

    Meanwhile, 3 manufacturers who sell pellets in the Dutch area claimed they all had low calcium pellets. Well, it turned out to be untrue. They don’t list the calcium content, but it turns out to be 0.6 – 0.75% if you ask them. So, I’m still offering low calcium dried veggies instead of pellets. It still works fine. I buy mine at, also known as Anined. They offer fresh dried veggies and I never had any issue with them. They also have other low calcium items which can be given as a treat: white oat (blanke haver), pine cone shoots (sparrescheuten), jasmine flowers, all which our pigs love a lot.

  11. Christine says:

    We just took our 18 mos old guinea pig to the animal hospital. They discovered a large stone that she will never be able to pass. She had a UTI and was not eating, and therefore, shutting down. They have stablized her with antibiotics, fluids, etc. and she is now pooping/peeing like she should. We are bringing her home today. We know there will need to be a diet change. What kind of pellet do you use? I’m trying to find a low calcium pellet, but I’m having trouble. I’m also going to try chanca piedra tea. We love her to pieces and are just broken up about this. Any specific information would be grately appreciated. Thank you so very much.

  12. Karine Jans says:

    I was told KMS has a low calcium pellet, but that’s not sold outside the US, unless you are willing to pay the high shipment costs and your local customs has to allow them in the country, which is not the case here.

    Is your piggie getting surgery?

    I use low calcium dried veggies instead of pellets (see list above). I use Timothy hay. We never, ever offer any vegs which aren’t low calcium, not even as a treat. It works like a charm! Woozy has been UTI and stone free for a year now. Hope this helps!

  13. ruby says:

    this is very helpful information for a a begginner like me i have 2 piggies both males,6 weeks old and the other one are 12 weeks,till now i dont have any idea what kind of veggies and fruits that is safe to give to them as their daily basis foods,aside from hays it would be very helpful if you give me a list 🙂 thank you 🙂

  14. nadine faulkner says:

    Hi there: I have read as well that for calcium, it’s not the total amount but the ratio, and that there should be a 2:1 ratio with phosphorous. This would be different from the .3 calcium diet you have. Have you heard of that? Also, what is your .3 diet – what is the food? My gp has the same problem, but his kidneys seem fine. He’s just had surgery for a big stone and a clot. So far so good, we’re on day 5 of recovery. But I had been giving him a 2:1 ratio for calc/phos, but it clearly didn’t seem to work… Can you give me your diet ingredients?

    Here is the website that says it should be 2:1 ratio…

    • Karine Jans says:

      Being a chemist, I know all about the Ca/Ph ratio and that’s the fiirst thing I asked the university professor vet, telling him that as far as I can see, my ratio is fine. He told me that the ratio is much less important than the level of calcium, calcium amount comes first.

      The list of 0.4 max veggies is in the comments here. 0.3 is hard to do, as then there is no balance between variety and vitamin C levels, so I had to switch to 0.4 from the start. I have kept Woozy, the twin sister of Whoopy who died, on this for 1.5 year so far and it works like a charm, including Timothy hay and 0.38 calcium bottled water. I never, ever go above 0.4, not even as a treat, as was ordered by the vet. Woozy has the same disease as her sister. The other pigs benefit from this diet as well and I will never again change it.

  15. Karine Jans says:

    Woozy lived calcium issue free till the day she died. I have not stopped using the low calcium diet after she died, as it worked so well.

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