You don’t need to consider protein – protein has no effect on developmental orthopedic disease. What you want to look at is calcium per 1,000 kcal. You can use calcium percentages as a guideline but they aren’t super accurate because they don’t account for differences in caloric density – for example if Brand X is 1.3% calcium and contains 500 kcal. per cup and Brand Y is 1.3% calcium as well but contains only 350 kcal. per cup your dog will be consuming much more calcium eating brand Y to fulfill it’s energy needs than it would be eating on brand X. 1.9% calcium is very high – you can rule out a food this high in calcium without even calculating the calcium on a kcal. basis. Generally foods with over 1.2% calcium are going to be too high although I’ve seen a few very calorie-dense foods in the 1.3%-1.4% range that are okay. To calculate grams of calcium per 1,000 kcal. you would multiply 1,000 grams by the percent calcium to obtain grams of calcium per kilogram. You would then divide grams of calcium per kilogram by calories per kilogram to obtain grams of calcium per calorie. You then multiply grams of calcium per calorie by 1,000 to obtain grams of calcium per 1,000 calories – aim for no more than 3.5 g.
I’ll use TOTW’s Southwest Canyon as an example:
1.9% calcium as fed/3,600 kcal./kg.
(1,000 g.)(0.019) = 19 grams calcium per kg.
(19 g. calcium/kg.)/(3,600 kcal./kg.) = 0.00528 g. calcium per kcal.
(0.00528 g. calcium per kcal.)(1,000 kcal.) = 5.28 g. calcium per 1,000 kcal.
This food has over 1 1/2 times as much calcium as a large/giant breed puppy should have.
