One of the barriers to feeding dogs raw food is the misleading notion that balancing and creating canine diets is an exact science that must be performed in the laboratory. This couldn’t be further from the truth! Raw feeding has a few guidelines that must be followed and the most important one is balancing the minerals calcium and phosphorus in the diet.
Meat is very high in phosphorus. The main function of phosphorus is in the formation of bones and teeth. It plays an important role in the body’s utilization of carbohydrates and fats and in the synthesis of protein for the growth, maintenance, and repair of cells and tissues. It is also crucial for the production of ATP, a molecule the body uses to store energy. Phosphorus works with the B vitamins. It also assists in the contraction of muscles, in the functioning of kidneys, in maintaining the regularity of the heartbeat, and in nerve conduction.
Bone is high in calcium. In addition to its widely known role in bone structure, calcium is used to help control muscle and nerve function, as well as to manage acid/base balance in the blood stream.
Dogs need a balance between the amount of phosphorus and calcium they get in their daily diets. In dogs, the calcium:phosphorus ratio should be about 1.2 to 1.5:1 although a range of 1:1 to 2.5: 1 is sufficient. That means that dogs should consume a little more calcium than they do phosphorus.
According to the Merck Veterinary Manual, less phosphorus is absorbed at the higher ratios, so an appropriate balance of these two minerals is necessary. Also, insufficient supplies of calcium or excess phosphorus decrease calcium absorption and result in irritability, hyperesthesia, and loss of muscle tone with temporary or permanent paralysis associated with nutritional secondary hyperparathyroidism. Skeletal demineralization, particularly of the pelvis and vertebral bodies, develops with calcium deficiency.
Excess intakes of calcium are more problematic for growing large and giant breed dogs. Too much calcium causes more severe signs of osteochondrosis and decreased skeletal remodeling in young, rapidly growing large breed dogs than in dogs fed diets with lower dietary calcium.
Balancing The Calcium:Phosphorus Ratio
It might seem daunting for dog owners to calculate the calcium:phosphorus ratio in a home prepared raw diet but it’s really not that complicated. Bones are a safe source of dietary calcium and if dogs consume enough of them, the diet will be balanced without a lot of difficult calculation.
Chemist Mogen Eliasen explains. “In the food we feed, we might have a deficiency of calcium. Let’s say that the food contains only half the calcium it should (50 milligrams instead of 100 milligrams), but is okay as far as phosphorous goes. We are thus out of balance – our 1:1 ratio is only 0.5:1 – which is critical.
“But, let’s say that we now feed 10 grams of raw bone. This will give us a total supplement of 1,000 milligrams of Calcium and 1,000 milligrams of Phosphorous. Add to this what we feed through the other sources of food. This brings the Calcium intake up to a total of 1,050 milligrams, and the Phosphorous to a total of 1,100 milligrams.
“Our overall balance is now no longer 0.5:1, but (1050/1100):1 = 0.95:1. We are only 5% “off”. But 5% is within the natural variation anyway, so it won’t matter… (Also: most standard chemical analyses do not give a more precise result anyway: +/-5% is pretty accurate for such an analysis…)
“If you feed 100 grams of bone instead, you will see the ratio go to 0.995:1 - less than 0.5% off the mark.”
Overall, balancing calcium and phosphorus isn’t all that difficult, as long as dogs receive plenty of bone. In general, any bone content over 10% is plenty although you shouldn’t exceed 25% because dogs need other nutrients too.
Bone Content In Raw Foods
When sourcing bones for your dog’s diet, it’s a good idea to know the approximate amount of bone in commonly sourced foods. Here is a quick guide to help you keep your dog’s bone content in the right range; between 10% and 25%.
Whole chicken (not including the head and feet): 25% bone
Leg quarter: 30%
Split breast: 20%
Whole turkey: 21%
Whole rabbit (fur and all): 10%
Whole (dressed): 25-30%
The bone content values in this list are an approximate but that’s really all you need to provide your dog with a safe and healthy raw diet. Avoid grocery store meats as they can be treated with bleach or enhanced with salt. You should also feed bones that are appropriate for the size of your dog. Avoid pieces that could present a choking hazard .