Nutritional Guidelines- Vitamin Doses, Etc.

Doses and guidelines

The following information is designed to help you create a better, more balanced diet for your tortoise. Sources and formulas are given at the bottom.

 Weight1          Length1  Calories2  Fat3  Protein3  Carbs3  Calcium4  Vit. A5  Vit. D5,6  Vit. E5
 grams/ounces  cm/inches  Daily needs- active  grams  grams  grams  milligrams,
min-max		  IU’s,
min-max		  IU’s,
min-max		  IU’s,
min-max
 50gr/2oz  6.4cm/2.5in  6 calories h- 0.3
o-1.5 		 h- 1.2
o-1.5  		 h- 4.5
o-3 		 11-19 mg 2.5 – 5 IU 0.25 – 0.5 IU 0.025 – 0.05 IU
 100gr/4oz  8cm/3.25in  12 calories     h- 0.6
o- 3 		 h- 2.5
o- 3		 h- 9
o- 6		 21-36 mg  5 – 10 IU  0.5 – 1 IU  0.05 – 0.1 IU 
 250gr/8oz  11cm/4.25in  20 calories h- 1
o- 5		 h- 4
o- 5 		 h- 15
o- 10		 36-60 mg  12.5 – 25 IU  1.25 – 2.5 IU  0.125 – 0.25 IU 
 500gr/1lb  14cm/5.5in  32 calories     h- 1.5
o- 8 		 h- 6.5
o- 8 		 h- 24
o- 16		 57-96 mg  25 – 50 IU  2.5 – 5 IU  0.25 – 0.5 IU 
 750gr/1.5lb  16cm/6.25in  48 calories h- 2.5
o- 12		 h- 9.5
o- 12		 h- 36
o- 24 		 87-144 mg  37.5 – 75 IU  3.75 – 7.5 IU  0.375 – 0.75 IU 
 1kg/2lb  17.5cm/7in  64 calories h- 3
o- 16		 h- 13
o- 16		 h- 48
o- 32 		 115-192 mg  50 – 100 IU  5 – 10 IU  0.5 – 1 IU 
 2.5kg/5lb  23.5cm/9.25in  107 calories h- 5.5
o- 27		 h- 21.5
o- 27 		 h- 82
o- 54 		 193-321 mg  125 – 250 IU  12.5 – 25 IU  1.25 – 2.5 IU 
 5kg/11lb  30cm/11.75in  214 calories h- 10
o- 54		 h- 43
o- 54		 h- 162
o- 108		 385-642 mg  250 – 500 IU  25 – 50 IU  2.5 – 5 IU 
 7.5kg.16.5lb  34cm/13.5in  290 calories h- 14.5
o- 73		 h- 60
o- 73		 h- 215
o- 146		 522-870 mg 375 – 750 IU 37.5 – 75 IU 3.75 – 7.5 IU
 10kg/22lb  37.5cm/14.75in  360 calories h- 18
o- 90		 h- 72
o- 90		 h- 270
o- 180		 648-1080 mg  500 – 1000 IU  50 – 100 IU  5 – 10 IU 
 50kg/110lb  64cm/25in  1200 calories h- 60
o- 300		 h- 240
o- 300 		 h- 900
o- 600		 2160-3600 mg  2500 – 5000 IU  250 – 500 IU  25 – 50 IU 
 100kg/220lb  80.5cm/32in  2275 calories h- 120
o- 600		  h- 480
o- 600		  h-1800
o-1200		  4100-6800 mg  5k – 10k  500 – 1000  50 – 100

Formulas and sources

1. Length/Weight:  SCLcm3x0.191=WTgr, or the ‘Straight-line Carapace Length’ in centimeters, cubed, times 0.191 gives you the predicted weight in grams. If the tortoise is lighter than the predicted weight, it is probably dehydrated. You can learn more about the formula on the ‘Healthy Weights‘ page. (Donoghue)

2. Daily Caloric Need:  WTkg0.75x72=KCalories, or, the weight in kilograms, to the 0.75th power, times 72 gives you the estimated daily calorie needs for an active tortoise. This would be reduced for an inactive or not growing tortoise (recovering, aged, winter time torpor, etc.) or increased for a very active tortoise (mating, nesting). (Mader, p.253)

3. Ratio of Calories from Fats, Proteins, and Carbs:  ‘H’ is for ‘herbivorous’, and ‘O’ is for ‘omnivorous’. Omnivorous reptiles should get about 50% of their calories from carbs, and 25% each from fats and proteins. Herbivorous reptiles get 75% from carbs, 20% from proteins, and only 5% from fats. (Mader, p. 255)

4. Calcium:  1.3 to 8mg x Kcal (or, for every Calorie of food, there should be 1.3 to 8mg of calcium). Phosphorous should be between 0.5 to 1 times the calcium dose. (Mader, p. 287)

5. Vitamin A, D, and E Ratios: The basic formula is a ratio of A:D:E of 100:10:1 (Davis)

6. Vitamin D dosage: (Source: Mader, p. 1069) Formula for mammals is 10-20IU/kg of body weight a day. Since reptiles have roughly half the mammal’s metabolism, using 1/2 of that dosage 5-10IU/kg/day seems to work well. Vitamin D toxicity is rare, and most often seems to occur when over 50 times the recommended dosage is given for weeks at a time. The primary symptom of vitamin D overdose is calcification of the soft tissues. Vitamin D toxicity is not an issue when the D is delivered by UVB lighting.

Note: Numbers and dosages have been rounded. I cannot guarantee that the math or application of the formulas is accurate- just the best I can do.

Resources

  • Davis, Sam, “Husbandry and breeding of the Red-footed tortoise, Geochelone carbonaria, at the National Zoological Park, Washington.” International Zoo Yearbook, 19: 50-53. 1979
  • Donoghue, Susan,1997. “Nutritional status of tortoises using morphometrics to assess body condition”. Vivarium Magazine, Volume 8 Number 2
  • Mader, Douglas R., DVM, ed. Reptile Medicine and Surgery. Saunders Elsevier, 2nd Edition 2006. ISBN 072169327X


Edited 8-15-2012


Updated- Mark Adkins (C) 6-8-2012