More on the Subject of Bladder Stones & Diet

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Sef
Supporter in 2019

Post   » Fri Nov 15, 2019 8:29 am


Sherwood and the LA Rescue have been quick to insist that there is no data that points to a connection between the formation of sludge and bladder stones and rabbit/guinea pig diets that are excessively high in calcium. I have seen numerous studies and reports over the years, and wanted to post this one as an example of why the recommendation by most vets is to limit calcium in guinea pigs who are prone to sludge and stones. It's not an arbitrary, non-fact-based recommendation; there is valid science to back it up.

Dr. Dan Johnson is, I believe, the veterinarian who was on the Board at Oxbow at one time. His credentials as an exotics vet and researcher are extensive. His paper entitled, "Rabbit Calcium Metabolism, Bladder Sludge, and Urolithiasis" talks about the way in which rabbits (and guinea pigs) process calcium, and why an overload of calcium in the diet can be problematic. Although he does state that reducing calcium alone is not a cure-all (he cites other factors that can contribute to sludge and stone formation), he makes the point that, based on the unique way in which these animals process calcium, it's prudent to reduce the calcium load for those animals who are prone to producing sludge.

Rabbit Calcium Metabolism, Bladder Sludge and Urolithiasis (Proceedings)


Although this was written a decade ago and is specific to rabbits, the information is still valid and relevant when talking about how calcium is processed in both rabbits and guinea pigs. Interestingly, Johnson also mentions Ca:P ratio, which is something I have questioned over the years:
The unusual calcium metabolism of rabbits makes it essential to maintain a diet that is well-balanced with appropriate calcium concentration, calcium to phosphorus ratio, and vitamin D content. If too little calcium is consumed, secondary hyperparathyroidism and bone resorption may result, while if too much calcium is present, the risk of urolithiasis and bladder sludge is increased.

Maybe we can use this topic to share other scientific data on the subject. I will add that, earlier this year, I invited a representative of Sherwood to post something on GL that explains the 'science' behind their claims that high calcium does not increase the risk of sludge or stones in guinea pigs, but she declined---citing a strong bias on the part of most pet owners against feeding alfalfa.

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Sef
Supporter in 2019

Post   » Fri Nov 15, 2019 9:44 am


This is an interesting study performed by a lab in Vienna back in 2006:

Urolithiasis in Guinea Pigs - Nutritional Aspects

The study sought to look at the effects on urinary pH when feeding a pellet + hay diet vs. fresh vegetables + hay diet:
Veterinarians are often asked for diet plans for rabbits or guinea pigs suffering from urolithiasis. As urine specific gravity and urine pH are parameters which significantly influence the solubility of the different urolith forming minerals, the aim of this trial was to evaluate the impact of various nutrients on these parameters in guinea pig urine…and on stone formation.
The results of this 5-day test on 16 guinea pigs was that feeding fresh feed (salad, apple, carrot) increased urine volume and decreased pH values and specific gravity in urine. The conclusion is stated as follows:
Green[s] contribute to abundant urine production in guinea pigs and as a consequence, to a lower specific gravity. pH values were significantly less alkaline when fresh feed was given compared to the control diet [of pellets and hay]. In conclusion, guinea pigs should be fed hay and fresh feed to minimize the risk of urolith formation...and with the benefit of preventing adipositas [obesity].

This data would seem to contradict the theory that it is beneficial to limit/remove fresh vegetables from the diet.

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Lynx
RESIST

Post   » Fri Nov 15, 2019 10:09 am


I made this a sticky for now. It may be worthwhile to repost it in the Records forum too (without any comments from this one).

I have always been grateful for your pushing me to do a stones page and your contributions to it.
http://www.guinealynx.info/stones.html

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Sef
Supporter in 2019

Post   » Wed Nov 20, 2019 12:02 pm


Here is another interesting article from that same website:
Urinary Diseases of Exotic Pets by Dr. Julia Whittington, DVM

From the author:
Urine is a major route of calcium excretion for rabbits (45-60% compared to <2% in other mammals). An increase in dietary calcium directly corresponds to increases in urinary excretion of calcium...A degree of calciuria is normal in rabbits and guinea pigs, however excess calcium precipitate or decreased fluid output results in thick paste, or sludge.
Small mammals with urolithiasis or hypercalciuria often have a history of limited exercise, making them prone to obesity, and a diet of free-choice pellets and alfalfa hay, which is high in digestible calcium.
Increasing water consumption is arguably the most important factor in preventing hypercalciuria or urolithiasis...Limiting dietary intake of calcium is also important. Feeding pelleted food formulated from grass hay and limiting exposure to alfalfa hay is recommended.

I'll keep digging, but I have yet to find a single resource anywhere that advocates increasing calcium in guinea pigs or rabbits who are prone to sludge or stones (see discussion: viewtopic.php?f=8&t=77760).

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Lynx
RESIST

Post   » Wed Nov 20, 2019 7:32 pm


More helpful information! This pretty clearly follows what we have been recommending for years.

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Sef
Supporter in 2019

Post   » Sat Nov 23, 2019 10:17 pm


I'm adding another relevant article here:
Urinary Tract Disease in Rabbits & Guinea Pigs


Interesting comment with regard to non-acute renal failure in rabbits and presumably guinea pigs, which may point to yet another potential health problem where high dietary calcium is concerned (highlighting mine):
Chronic renal disease and failure has many causes...Noninfectious causes include prolonged hypercalcemia and vitamin D toxicity; excessive dietary calcium levels result in calcium being deposited in kidneys (and aorta)...

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pigjes
Cavy Comic

Post   » Sun Nov 24, 2019 10:12 am


Very interesting finds!!! Thanks!

Bookfan
For the Love of Pigs

Post   » Sun Dec 01, 2019 3:10 pm


I'm coming back to this. Can't read it now.

gwinny_piggies

Post   » Mon Dec 02, 2019 11:34 am


When you say the LA Rescue do you mean this one?https://m.youtube.com/channel/UCnY3dhKVuHUr4yOqpNSpoOw

I remember watching this lady back when I needed help on syringe feeding critical care but I really hope it's not who you're talking about since I know LA is a big place as well..

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Sef
Supporter in 2019

Post   » Mon Dec 02, 2019 11:48 am


This topic was in response to a related discussion on GL, found here:
viewtopic.php?p=2302505#p2302505

Bookfan
For the Love of Pigs

Post   » Sun Dec 15, 2019 10:41 am


"Increasing water consumption is arguably the most important factor"
This is something our vet always pushes for stone/sludge pigs.

Would a pig be ok if you significantly decreased or stopped pellets, making sure they got a vitamin C supplement & lots of hay? Along with some appropriate, low calcium veggies & plenty of water?

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