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What Causes Pyramiding? - Darrell Senneke
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Deformities, Improper Growth or "Pyramiding"? - Chris Tabaka DVM and Darrell Senneke
I have come to see pyramiding as being the end result of the any one or usually a combination of these six things. In my examples I will use various tortoises, as some are more prone to pyramiding than others. The following is a melding of recent discussions on this subject. This is not intended as the final word on this subject, merely a compilation of personal learning on this matter. We do not know everything about Tortoise nutrition and exactly what causes pyramiding. This is my opinions based upon personal observation.
Pyramiding has been attributed to six things:
Too much protein
Too much food
Low fiber foods
Lack of exercise
Too much protein (plant or animal) is the most well documented cause for pyramiding. There are accounts of wild tortoises that exhibit pyramiding because of high protein foods in their diet. High protein diets are also physically stressful and are believed to damage the kidneys in addition to contributing to the stacked look.
Too much food is a real problem. Especially with Geochelone sulcata, Testudo hermanni and Testudo horsfieldii-the tortoises literally eat themselves into trouble. This is the type of pyramiding that seems to be exhibited by the conical scutes. People, especially in the north, see this a lot regardless of how much calcium they supplement. My feeling is that the body is much better at removing protein from the food than calcium; the calcium passes through and the protein is converted to the keratin that results in the 'stacked' look. In an effort to keep up, the bone becomes porous and sponge-like. Regardless of how low in protein the diet is, too much food may result in pyramiding. In groups of Redfoot and Leopard tortoises where most are perfect I have seen one or two that showed light pyramiding, and usually they are the heaviest eaters.
Inaccessible calcium or low calcium seems to present itself more as a flattened appearance with collapsed vertebral scutes. Tortoises seem to preferentially put the available calcium in the plastron. This is a result of poor food or a steady diet of high oxalate foods. I have seen this in Geochelone radiata, Geochelone pardalis, Testudo hermanni, and, recently, a Testudo horsfieldii. Lack of UVB exposure for vitamin D conversion is another cofactor for this problem.
Low fiber - In my opinion, low fiber foods yield the same results as too much food because they are too digestible. A look at the droppings of grass-fed tortoises shows them to be fibrous and still containing a lot of vegetative integrity. Looking at store produce droppings shows them to be watery. Every Leopard owner I know in the north has trouble with this in the winter when grass (or grass hay) is not available. Interestingly, feeding alfalfa, even though high in protein, seems to not result in much pyramiding, I assume because of the fiber.
Physical activity levels in proper in protein/calcium metabolism are necessary for a sound skeletal frame. If you look at people's pens for their tortoises, even the best setup does not give them as much room as in the wild. It is known that high levels of physical activity lead to more calcium being deposited in bone (human studies). This goes a ways towards explaining the generally smoother shells of tortoises raised mostly outdoors in the South and Southwest as compared to those in the North.
Hydration status has also been suggested as another important cofactor. This is an interesting subject in itself. There have been studies subjecting tortoises to high protein diets while also providing very high hydration states. The jury is out on kidney and liver functions and time will tell on those, but externally there have been cases of very rapid growth with high protein while achieving smooth shells at the same time. The thought is that the very high water throughput is flushing the system sufficiently to avoid pyramiding. As a result of this it is suggested to provide high humidity hide boxes even in arid habitats.
In closing, here's another example: I have a friend who owns an Aldabran tortoise (Geochelone gigantea). It has developed semi-severe pyramiding, yet I know that this animal gets the lowest protein 'best' foods available. I think that the pyramiding in this case is a result of too much food and almost no exercise.
So, in brief, I strongly suggest avoiding protein for animals that are totally herbivorous in nature. But all of these other factors should be taken into account as well. To best avoid pyramiding feed a low protein diet. Watch the volume fed because more is not necessarily better. Use a calcium supplement and provide exposure to UVB light to facilitate absorption. Provide high-fiber foods. Provide a large enclosure, since exercise is a key component in proper metabolism. And provide a water source at all times; tortoises in the wild have access to microclimates that we cannot provide. Even tortoises that would have little contact with water in the wild must have it in captivity.
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