How to Raise Sulcata Tortoises to Prevent Bladder Stones

How to Raise Sulcata Tortoises to Prevent Bladder Stones
By Assist. Prof. Dr. Sompoth Weerakul (Dr. Kaew)

There are four key points we need to understand regarding this issue:

What type of stones do Sulcata tortoises develop?
How do these stones form?
How can we identify the symptoms?
How can we prevent them through proper husbandry?

Point 1: The Type of Stones
For a long time, it was widely misunderstood that the most common stones in these tortoises were Urate stones, caused by uric acid accumulation from high-protein diets or kidney disease (which typically leads to Gout).

However, research shows that stones in Sulcata tortoises are often unrelated to urates or uric acid. Instead, they are primarily "Calcium Oxalate" stones. Sulcatas are at the highest risk for this type of stone, which can be found in tortoises as young as two months old. While oxalate can also bind with magnesium, sodium, or potassium, Calcium Oxalate remains the most prevalent.

Point 2: How Calcium Oxalate Stones Form
While other tortoises face similar risk factors, Sulcatas are uniquely prone to these stones due to two main factors: Diet and Hydration.

Dietary Risks: Feeding plants high in Oxalic Acid, such as certain vegetables, young leaf buds, sprouts, flowers, or young plants, as well as various fruits.
Hydration Habits: Sulcatas are arid-land tortoises that primarily obtain moisture from their food (preformed water) rather than drinking directly (free water). Low water intake results in a decreased ability to flush out oxalic acid and calcium oxalate crystals, leading to accumulation.
The Formation Process: When a Sulcata regularly consumes high-oxalic acid plants, the acid binds with calcium in the body to form crystals or stones. These can be found in the digestive tract (Gastroenteroliths) or the urinary system (Uroliths), including the kidneys and bladder.

Because the process "steals" calcium from the body, it often leads to a calcium deficiency. The tortoise will then pull calcium from its own bones and shell. In adults, this results in soft shells (especially the plastron or belly shell) and deformities. In juveniles, it leads to stunted growth and incomplete shell development.

Point 3: Symptoms and Detection
As stones grow larger, they press against the abdominal and thoracic cavities, causing difficulty breathing. You may notice the tortoise extending its neck, spreading its legs, or lifting its body to gasp for air—symptoms often mistaken for a respiratory infection.

The most common signs owners report to veterinarians include:

Loss of appetite (Anorexia)
Constipation or straining to defecate/urinate
Lethargy
Stunted growth
Soft or deformed shells (even if the shell was previously hard and healthy)
Point 4: Prevention through Husbandry
Prevention focuses on managing the risk factors mentioned in Point 2.

Dietary Management:

Avoid prolonged feeding of young plants: Young greens have high oxalic acid levels.
Switch to "Mature" plants: Older leaves and mature grasses have lower oxalic acid and higher fiber, which stimulates digestion.
Fiber Supplementation: Use formulated hay powders, such as Timothy Meal (e.g., RANDOLPH), to mix with vegetables. This increases fiber, adds essential vitamins/minerals, and dilutes oxalic acid intake.
Rotation: Offer fresh vegetables only 1–2 days a week, focusing on mature grasses and leaves the rest of the time.
Pelleted Feed: If growth is slow due to a high-fiber diet, high-quality tortoise pellets (mainly grass-based with fiber levels up to 27%) can provide necessary energy and minerals for healthy development (e.g., Tortoise Care, RANDOLPH).
Increasing Hydration:

Misting Food: Spray water directly onto their greens, as they primarily hydrate through eating.
Soaking: Regular soaking allows water intake through the cloaca. The hormone Arginine Vasotocin (AVT) stimulates the cloaca and colon to absorb water through "Aquaporins" in the intestinal wall. This is excellent for both prevention and therapy, though excessive soaking may occasionally affect the aesthetic texture of the scutes.

Conclusion
This condition is not a "mystery disease"; the science behind it is quite clear. In the next article, I will discuss diagnosis and both medical and surgical treatment options to help veterinarians and keepers understand the best practices for care.