I have dealt with sludge, suspected bladder stones and osseous choristoma/metaplasia in my guinea pigs -- all problems of "excess calcium". What I've found was that restricting calcium intake didn't help. I eventually came to suspect their problems were due to a lack of sunlight. Even though they have filtered light indoors, they only ever go outside during early morning and late afternoon when the sun is not directly over head. I asked my vet about this, and was told they are crepuscular animals - active at dawn and dusk, and rarely get much sun in their native habitat.
Eventually, I also learnt lack of magnesium also has something to do with calcium not being deposited in the bones where it should, but in soft tissues where it shouldn't.
So here is my take. The problem of "excess calcium" in blood, tissue or urine in guinea pigs eating a relatively normal calcium diet for their age is usually one of calcium not being absorbed into bones (and whereever else it should go), and being wrongly deposited in the soft tissues or excessively excreted through urine. Adequate vitamin D (from sunlight) helps calcium to be absorbed from the diet, and not excessively excreted through urine where they can potentially cause problems in the bladder. Adequate magnesium helps calcium to be deposited into bone, and not randomly deposited into other soft tissues or joints where they can cause osseous choristoma and other problems. I stress this is adequate vitamin D and magnesium for normal calcium levels.
Calcium excess to their dietary needs of course will cause problems, but what I am saying is most cases of "excess calcium" is a lack of other vitamin D and magnesium in relation to normal calcium.
There has already been a thread on magnesium in Cavy Chat: http://www.guinealynx.info/forums/viewtopic.php?t=69198
I also found this on Google Books - Laboratory Animal Medicine
edited by James G. Fox, Lynn C. Anderson, Franklin M. Loew, Fred W. Quimby, page 235:
"Calcium and phosphates in excess increase the requirement of magnesium, which contributes to the problem of metastatic mineralization, described below."
It talks about more minerals involved in calcium balance, that no vet I've yet encountered seems to know about or talk about.
So anyway, here are my thoughts on the "excess calcium" problem so far. I thought I'd start a thread for anyone interested to continue the research.
Anyway, any thoughts on magnesium in this puzzle?
"The probable cause, or one of the causes, of the various abnormalities is a primary magnesium deficiency or diets high in calcium and phosphates and low in magnesium." and "Local tissue low pH may also be involved."
- Cavy Comic
He swears by using a low calcium diet only, as most diets are well balanced regarding phosphor anyway. Many people have a hard time keeping it up, as its very strict. It means low calcium hay, treats, water, vegs and pellets all the time, no exception to the rule.
Here is the entire story:
I have used the diet with success.
He also told me to reduce the sunlight bulb use to 20 minutes a day. Vitamin D actually helps to increase calcium excretion and the concentration of calcium in the bladder gets too high, so it makes it easier to form stones. Pigs in the wild live in high grasses and don't get much sunlight either, especially as they are only active during twilight hours.
As far as magnesium goes: veggies contain a lot of it. So, that should certainly suffice.
I am a chemist myself, specialized in food, so I am not pulling this out of my sleeve: There are other chemicals and factors which have an impact on calcium stone formation, not only phosphor, or the amount of calcium, but stuff like genes, oxalates combined with vitamin C, citrates, phytates, sodium, too much veg protein, purine, genetic predisposition, level of water intake, the actual physicalities of the urinary system differs individually, illnesses, obesity, etc. Here are some links. Humans are genetically close to piggies, so I can refer to these.
http://books.google.be/books?id=LlJy5XJOkSkC&pg=PA119&lpg=PA ... tion&f=false
With regards to vitamin D, I know vitamin D helps the absorption of calcium from the gut, but I'm not sure how excess vitamin D in the absence of excess calcium will increase calcium excretion. Here is a recent study on humans that says vitamin D does not contribute to kidney stones: http://www.sciencedaily.com/releases/2013/10/131017173352.htm
The GL bladder stones page says adequate vitamin D is necessary for "proper absorption of calcium", which coincides with my thought that that lack of vitamin D will also allow calcium to be excreted through the urine. So, a study that concludes with "as vitamin D deficiency is highly prevalent among stone formers" in humans, (but didn't find out much else): http://www.ncbi.nlm.nih.gov/pubmed/23739765
As for magnesium, you said veggies contain a lot of it - could you elaborate?
The links you shared - I haven't read all of it (and cannot access some). I'll take your word that there are a lot of factors in stone formation, which I'm sure is the case. If I understand you correctly - are you saying that normal calcium can also cause bladder/kidney stones as there are other factors involved? But what I'm trying to understand is, how normal calcium itself cause the problems of calcification (including bladder stones) when there is inadequate vitamin D and magnesium, which is somewhat different.
Anyway, I don't have the time to do much more research into this, but magnesium in particular seems to be an overlooked area, and yet there is research into this that dates back to the 70s and 80s.
It seems to have been forgotten? I felt an obligation to bring this up, but I really don't have time to continue googling for references, nor am I saying what I have said is all true and correct. Please, for all those who think there is something to this, and want to look into it, post your finds.
- Supporter in '14
I am starting to wonder if the pellets we are using are too good. How much nutrition do guinea pigs that are not producing several litters in their lifetime need? My vet pointed out that in the wild guinea pigs probably survived on a sparse diet of dried grasses for most of the year. These pigs have a very active life and they produce many litters and probably only live a couple of years.
Our guinea pigs are pampered, given the best food we can get, sit around most of the day in a warm soft cage and don't use up their calcium supply producing offspring. Maybe their bodies just don't need all the concentrated vitamin supplements in the pellets. I have cut way back on the pellets, others have chosen to go without pellets and these pigs do just fine.
- Cavy Comic
Guinea pigs in the wild eat live grass mostly. By grass, don't compare it with the grass in our backyards. There are about 10 000 types, the stuff they eat in the wild is much different.
You can compare a guinea pig's vitamin and mineral needs with humans, take the size difference in account. I spoke to a pellets manufacturer representative once and they said that pellets are well balanced regarding of what pigs need daily and that a decent pellet should even cover an entire dietary need. Looking at them from a chemist point of view, looking at the ingredients and quantities, that seems about right.
Granted, not all pellets are OK, some are too colored with bad colorants (some use natural colorants which are OK), some are too starchy, some contain a bit too much vitamin A, contain too many "sugars", some use bad preservatives, too much salt, etc. By salt, I don't only mean kitchen salt, but also all other mineral salts.