Did the math - nutrition

[Crowfingers]

Feel free to move this if it should go somewhere else :/

I've been studying animal nutrition and learned a really cool formula from the IWRC manual to figure out how many kcal / day and grams per feeding various animals need, and decided to try it on my snake, and it actually worked! It's a lot of math, but it's here if your interested (the 10-15% is way easier)

The formula: taxonomic constant x (weight in kg)^0.75 x 1.5 x physiological factor = kcal/24 hours
- the taxonomic constant for ectotherms is 10
- I used the 'growth' range of the physiological factor which is 1.5 to 3.0 (it changes if the animal is sedentary/sick/injured/trying to gain or loose wt)
- my snake weighs 345g or 0.345 kg
- he eats whole rats that are between 10g and 50g and the break down for the nutrition of this prey is (prey size and type changes all these factors too):
Dry Matter 30.00%, protein 16.83%, fat 8.25%, calcium 0.62%, phosphorus not given, g/kcal 1.67


Step 1: BMR (basal metabolic requirement) = taxonomic constant x (weight in kg)^0.75
(10)x(0.345 kg)^0.75
(10)x(.4502)
BMR=4.502

Step 2: MMR (maintenance metabolic requirement) = BMRx1.5
(4.502)x(1.5)
MMR= 6.753

Step 3: Kcal/day: Calculate the animal's daily requirements (range) based on physiological factor
MMR x physiological factor
(6.753)x(1.5) (6.753)x(3.0)
=10.1295 kcal/day =20.259 kacl/day

Step 4: Convert kcal/day to g/day
(10.1295 kcal/day) / (1.67 kcal/g) = 6.0656 g/day
(20.259 kcal/day) / (1.67 kcal/g) = 12.1311 g/day

Since I am feeding every 5 days, you multiply the g/day by 5 to get the total grams of rat he needs per feeding.
(6.0656 g/day)x(5)= 30.328g or ~30g
(12.1311 g/day)x(5)= 60.6555g or ~61g

Now this is close to a 9% to 18% of body weight of prey per feeding, rather than the much more common 10-15% of body weight of prey per feeding, but I was surprised at how close it came. This might be where this 'rule' for a growing snake came from...I'm not really a math nerd, I promise.

[Stewart_Reptiles]

So does your method apply for hatchlings as well as adults?



Sent from my SM-G900V using Tapatalk

[Crowfingers]

So does your method apply for hatchlings as well as adults?

It should for hatchlings since they are growing, the first three steps don't change, but for converting to grams per day, you would need to find the Kcal/gram of the prey, and also multiple by however many days you go between feedings. I'm not sure what you feed a hatchling, but the rat nutrition I used is specifically for a Norway (domestic) rat that is between 10 and 50 grams*.

*an adult rat (>50g) will have different nutrition ratios and kcals

Adults, I guess would have a different physiological factor. The closest the book has that MIGHT work for adults is 'physical inactivity' at a range of 0.7 to 0.9 - unless you have active snakes, or are breeding them. All of the other physiological factors given are for specific illnesses/injuries since the book focuses on veterinary/rehabilitation scenarios. You probably don't feed every 5 days, so you'd need to change that factor too.

You can find a lot of the nutrition info on prey items from rodent pro, they have a great chart. http://www.rodentpro.com/qpage_articles_03.asp

[O'Mathghamhna]

Feel free to move this if it should go somewhere else :/

I've been studying animal nutrition and learned a really cool formula from the IWRC manual to figure out how many kcal / day and grams per feeding various animals need, and decided to try it on my snake, and it actually worked! It's a lot of math, but it's here if your interested (the 10-15% is way easier)

The formula: taxonomic constant x (weight in kg)^0.75 x 1.5 x physiological factor = kcal/24 hours
- the taxonomic constant for ectotherms is 10
- I used the 'growth' range of the physiological factor which is 1.5 to 3.0 (it changes if the animal is sedentary/sick/injured/trying to gain or loose wt)
- my snake weighs 345g or 0.345 kg
- he eats whole rats that are between 10g and 50g and the break down for the nutrition of this prey is (prey size and type changes all these factors too):
Dry Matter 30.00%, protein 16.83%, fat 8.25%, calcium 0.62%, phosphorus not given, g/kcal 1.67


Step 1: BMR (basal metabolic requirement) = taxonomic constant x (weight in kg)^0.75
(10)x(0.345 kg)^0.75
(10)x(.4502)
BMR=4.502

Step 2: MMR (maintenance metabolic requirement) = BMRx1.5
(4.502)x(1.5)
MMR= 6.753

Step 3: Kcal/day: Calculate the animal's daily requirements (range) based on physiological factor
MMR x physiological factor
(6.753)x(1.5) (6.753)x(3.0)
=10.1295 kcal/day =20.259 kacl/day

Step 4: Convert kcal/day to g/day
(10.1295 kcal/day) / (1.67 kcal/g) = 6.0656 g/day
(20.259 kcal/day) / (1.67 kcal/g) = 12.1311 g/day

Since I am feeding every 5 days, you multiply the g/day by 5 to get the total grams of rat he needs per feeding.
(6.0656 g/day)x(5)= 30.328g or ~30g
(12.1311 g/day)x(5)= 60.6555g or ~61g

Now this is close to a 9% to 18% of body weight of prey per feeding, rather than the much more common 10-15% of body weight of prey per feeding, but I was surprised at how close it came. This might be where this 'rule' for a growing snake came from...I'm not really a math nerd, I promise.

I like string.

[Crowfingers]

I like string.

LOL, I get bored. research is how I spend my free time...that and cleaning up after pets.

[O'Mathghamhna]

I'm very impressed. It's far more effort than most people are willing to put into diet! We do something similar for wildlife rehab, I'm sure this will help snakes with poor body mass and owners who aren't exactly sure how much to feed!

[Crowfingers]

I'm very impressed. It's far more effort than most people are willing to put into diet! We do something similar for wildlife rehab, I'm sure this will help snakes with poor body mass and owners who aren't exactly sure how much to feed!

Thanks!

[Lizardlicks]

It would be neat to put this all into a little app that allows for option selections then calculates it for you for those of us who are less math inclined!