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What you need to know about balancing the calcium to phosphorus ratio in a raw diet?


Switching to a raw diet may seem like a daunting task. There is so much information available and so many things to consider, are they getting enough bones or organ meat, have I missed an important mineral, am I feeding them too many carbs?


All valid concerns, but what if I told you raw feeding doesn’t have to be complicated?

Have a look at our 'Beginner’s guide to raw feeding’ to get you started on the basics. If you’ve already started on your raw journey or if you’re a seasoned pro how much do you know about the calcium to phosphorus balance and its importance for your dog?


If the answer is along the lines of nothing at all or I’ve never really thought about it, read on to find why it’s important and what you need to consider when making up your next raw meal. Don’t worry though it’s not as complicated as you might think.


Calcium


Calcium is an incredibly important mineral with several key roles in the body. Not only is calcium responsible for forming the skeletal structure and the cytoskeleton in each individual cell. It plays a vital role in blood clotting, as well as ensuring proper neuromuscular (the nerves communicating between the brain and muscles), cardiovascular (the heart, lungs and blood vessels), immune and endocrine (glands that produce and regulate hormones) function and maintaining cell membrane stability.


Bones have high levels of calcium.


Phosphorus


Like calcium, the main role of phosphorus is in building strong bones and teeth. However, it also plays an important role in the body’s ability to use carbohydrates and fats as energy, the production of ATP (the molecule responsible or storing and transferring energy in cells) and synthesizing protein to be used to grow, maintain and repair cells and tissue. Phosphorus also plays a key role in kidney function, heartbeat regulation, nerve conduction and muscle contraction.


Bones and muscle meat both have high levels of phosphorus.


What happens I there is too much of one or the other?


There are a number of issues that can arise from having insufficient or excess levels of one or both minerals. Delving into those conditions as a little beyond the scope of this article but if you are interested this 2018 article is great for some further reading.


What is the right balance?


The National Research Council made a recommendation in 2006 a ratio of 1.2/1 calcium/phosphorus for mature dogs. At present there is conflicting data when calculating the needs of puppies. This is because much of the existing research has been done on large or giant breeds with the theory that needs of small to medium dogs could be calculated based on caloric needs.


The accepted ratio for large and giant breed puppies is ~2/1 to 35 weeks then gradually decreasing until fully developed. This 2019 study proved that this ratio is not the same for small to medium dogs, in fact it would significantly overestimate their calcium needs.


The study goes on to suggest that a 1.4/1 ratio should be aimed for in small to medium dogs because of the known negative effects and oversupply can have on growing dogs.



How can I get it right?


The answer is far less complicated than you may think and really comes down to feeding the right percentage of bone to muscle meat. If you follow the general raw feeding guide of 10-15% of bone you will hit the recommended ratio with ease.


Here is a list of some of the common meaty bones and their percentage of bone.



Chicken

· Drumstick – 32%

· Wing – 45%

· Neck – 36%

· Feet – 60%


Turkey

· Drumstick – 20%

· Wing – 33%

· Neck – 45%


Duck

· Feet – 60%

· Neck – 50%


Pork

· Trotters – 30%

· Tail – 30%

· Ribs – 30%


Kangaroo

· Ribs – 60%

· Tail – 45%



Now that we know roughly the percentage of bone how do we convert that to a weight?


Simply weigh the item and multiply by the percentage to get the number of grams of bone.


For example;

If you are feeding your dog 2 chicken feet with a total weight of 50g

50g x 0.6 (60%) = 30g


Generally, the remaining weight will be meat, fat, sinew and ligaments so don’t forget to add the remaining weight to your daily meats and fats number. The exception to this would be if you are feeding heads, ie chicken or duck head. This is because the brain and eyes are considered organs.


How much Calcium and Phosphorus are they getting?


Not all bones have the same levels of calcium and phosphorus.


Let’s use chicken, beef and kangaroo bones as an example


Calcium Phosphorus

Chicken 550mg/g 280mg/g

Beef 194mg/g 103mg/g

Kangaroo 260mg/g 140mg/g


If we were to feed 30g of each we can see the significant difference in how much calcium and phosphorus we are actually feeding.


Calcium Phosphorus

Chicken 16.5g 8.4g

Beef 5.8g 3.1g

Kangaroo 7.8g 4.2g


What is interesting is that even though there is a huge difference in the gram amount among the 3 varieties the calcium/phosphorus ratio in each is very similar.


Chicken 1.9/1

Beef 1.8/1

Kangaroo 1.8/1


Don’t forget we are looking for a 1.2/1 – 1.4/1 ratio but we are going to get a lot more phosphorus, and comparatively very little calcium from our meat and fats which will bring the ratio down to where it needs to be.


So, what does all that mean?


Really, it just means that you need to mix up your bones. If you remember from our raw feeding basics, the average over time is more important than having everything perfect at every meal. If you are constantly feeding chicken bones you’re going to be getting high levels of calcium and could be throwing the ratio off. Likewise, if you always feed beef bones your ratio could end up low.


A variety of sources of meat and bones in the diet will help you to get that ratio to the ideal level.


In an upcoming blog we will look at the ratios we can get from meats and how we can use that to balance out what we are getting from bones. If you are working to the 70% meat, 10-15% bone ratio you should be hitting the calcium.

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