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What is the correct ratio of calcium and phosphorus for dogs?

What is the correct ratio of calcium and phosphorus for dogs?

  • 1. Introduction
    • 2. What is the correct ratio of Calcium and Phosphorus for dogs?
    • 3. How to balance a raw diet
    • 4. Is there any healthy kibble for dogs?
      • 5. How to prepare healthy natural dog food
        • Introduction

          In the 30 years of working as a vet, I have learned that repetition is at the core of achieving great health. I sometimes go out and talk to dog lovers undercover on my walks not telling them I am a vet. It is fun because that way they’re more open to share their experiences with their dogs and veterinarians, and I can see more clearly what I need to write about. 

          You may have not thought about it, but most vets, myself included, don’t really know what is going on in the exam rooms. It is because we usually do not need to go and see a veterinarian 🤓. But sometimes I wish I was a fly on the wall, to hear what my colleagues say and why many of you tell me my approach to medicine is different.

          There are two areas that concern me the most, based on my “undercover” discussions with dog lovers: Nutrition and Vaccination. Today, I will focus on nutrition and especially the calcium/phosphorus ratio in food in puppies and adult dogs.

          What is the correct ratio of calcium and phosphorus for dogs?

          It is actually surprising how hard it is to come across clearly stated Ca/P ratio recommendations supported by research. Based on the Merck Veterinary Manual, the Association of American Feed Control Officials (AAFCO) considers the following levels of Calcium and Phosphorus as acceptable:


          Puppies after weaning:

          A wide range of 2-18 g of Calcium per 1000 calories (with the recommended amount of 3 g) and 2.5 g of Phosphorus per 1000 calories.

          Adult Dogs:

          Minimum of 0.5 g of Calcium per 1000 calories (with the recommended amount of 1g) and 0.75 gm of Phosphorus per 1000 calories.

          To make the numbers clearer I have created the following table:

          Ratio of Calcium to Phosphorus

          The Merck Veterinary Manual also states that the amounts of nutrients may need to be modified up or down by 30%, which makes these figures vague. To make this even more confusing for well-intended dog lovers and pet food manufacturers, not every food digests the same way. For example, calories in meat are much more available than calories in fillers, such as cellulose, which is very common.

          Even if dog food contains the recommended amounts and ratios of Calcium and Phosphorus, dry food is much more calorie-dense, which results in overfeeding, fast growth and bone and joint growth issues.

          Naturally, all of this makes the decision about what kibble to choose very difficult for well-meaning and caring dog lovers because there are too many variables and a dog's individual nutrient requirements also need to be considered.

          I have seen many people experience a great deal of anxiety and worry, and I understand why. We veterinarians, along with pet food companies, have made dog nutrition extremely complicated, and the recommendations practically impossible to apply in real life.

          Who knows if this is or is not intentional, but the result is everlasting confusion, endless debates and most of all unnecessary suffering of puppies and adult dogs. 

          For many decades, the education of veterinarians in the field of nutrition has been done under the influence of processed pet food manufacturers who are in the business of selling kibble. For example, the Global Nutrition Committee that has been active at events such as WSAVA (World Small Animal Veterinary Association) conferences educates veterinarians in the field of small animal nutrition. The problem is that this committee is sponsored by 3 large processed pet food manufacturers, which makes it less credible in providing unbiased information.

          Can you ensure the correct ratio of calcium to phosphorus in your dog's food?

          For most dog lovers, it would be extremely difficult, if not impossible, to verify that their dog’s kibble contains the right ratio of Calcium and Phosphorus in connection with ME (metabolizable energy), based on the calorie availability (for example, meat vs. cellulose).

          As I mentioned above, cellulose (wood chips), or other forms of fibre and indigestible diet components, are used to bulk up the volume of food, but they are not a bioavailable energy source. You can also see practical evidence of this by comparing the bowel movement size from dogs on kibble vs. that of those on raw food. Kibble fed dogs produce a much larger volume of feces. The difference is striking!

          This means that while the Ca/P ratio per 1000 calories of food may look good on paper and in the lab, it can be completely off when it comes to bioavailable calcium and phosphorus.  

          What are the implications of all this?

          Having the opportunity to see thousands of dogs in practice, most of the growth-related issues I have seen, including hip dysplasia, cartilage growth disorders, fragmentation (osteochondritis dissecans), and growing pains (panosteitis) affect dogs on kibble.

          Dogs on such foods appear to grow faster, lankier, and weaker, similarly to over-fertilized plants that grow fast and weak. Kibble is much more energy dense. Dogs can consume more calories before they feel satiated, and the bioavailability of nutrients fluctuates heavily based on the ingredients. In other words, kibble fed dogs are “over-fertilized” too.

          Nature has the answer!

          Since I began feeding and recommending raw food in the late 90’s, I rarely see dogs being fed a raw or cooked whole-food diet affected by hip dysplasia, panosteitis or cartilage, joint, and abnormal growth disorders.

          Dogs fed raw or cooked diets that include meat, raw bones, and vegetables along with natural vitamins and other supplements for dogs, grow slower and are stronger. This allows the body to build good structure as well as healthy bones and joints, even in dog breeds that are supposedly predisposed towards these problems.

          Such an approach works consistently well, and I can say – with confidence – that a whole-food raw or cooked diet, including the essential supplements, yields far superior results and dramatically reduces growth abnormalities and bone and joint disease. I have seen this in my patients, and also in my own dogs.

          Instead of focusing on trying to follow the hard to apply Calcium/Phosphorus recommendations, or be misled by organizations sponsored by processed pet food companies, I recommend feeding our dogs a diet that is as close to the natural diet of canines as possible. Such a diet consists of a variety of meat, bones, and vegetables, and includes supplements.

          How to balance a raw diet

          How to balance a raw diet for certain breeds: Is there any difference?

          The simple answer is that there is no difference between food for small or large dogs. When you feed a raw diet, there is no difference between the 36 different species of the canidae family. There is a big difference in the size of wolves, coyotes, dogs, foxes, jackals, dingos, raccoon dogs, and fennecs, however, they have the same dentition, digestive tract, and diet.

          Family Canidae

          Photo Credit:

          ( More info here )

          Wolf cranium

          By William Harris - Own work, CC BY-SA 4.0,

          Is there a difference between a raw diet for puppies and adult dogs?

          In nature, as soon as puppies start accepting solid food, they start eating the same type of food as adults, and this continues all the way into old age. There is not a single example of a mammal eating different food during different stages of their life, with the exception of the early nursing stage.

          The life stage and breed based processed food idea is an invention of pet companies who need to create the impression that it is too difficult to feed a balanced home-based raw or cooked diet, which is not true.

          Humans are capable of feeding children a wholesome diet, and it’s no different for dogs.

          Most problems arise only if

          1. Dogs get kibble which is unnaturally calorie-dense and is made of ingredients dogs would not eat on their own, such as grain, corn, rice, and cellulose, to name a few.
          2. Their food lacks four essential nutrients: Minerals, Vitamins, Probiotics and Omega-3 fatty acids (EFA’s).

          Are dog food supplements necessary?

          I have dedicated the past 15 years towards the development and formulation of natural diet recipes and making them balanced by formulating essential nutritional supplements for dogs.

          I take this process very seriously because I am a dog lover and I understand how much your dog means to you. When I come up with a new formula I first test it on myself, as well as my family and friends, in order to understand its effects and ensure safety. We test on people first to make sure our products are safe for dogs.

          I had the opportunity to see the difference by raising my first pets on kibble in the early 90’s. I then fed my dog Skai a raw diet, without any supplements for the first 7 years of his life, and then added supplements for the remainder. I am now raising my current dog, Pax, who has been on a raw diet along with the FAB4 essentials from the age of 8 weeks.

          My patients and my own dogs have guided me to a place where I can say with confidence that a raw or cooked diet, along with essential supplements, provides solid repeatable results.

          Why is good food no longer enough?

          For the past 100 plus years, intensive agriculture has caused severe soil depletion, which reflects in depleted plants and meat. Such depletion has a severe impact on the health and longevity of our dogs, unless these nutrients are supplemented. This is why dog lovers report such dramatic changes after they introduce the essential nutrients, read more here.

          Younger animals that do not get enough nutrients may be lucky and they may be ok for a while, however, as they age, the differences become more pronounced.

          The Natural Nutrient Cycle

          Broken Nutrient Cycle of Today

          Is there any healthy kibble for dogs? 

          From my experience working with a community of hundreds of thousands of dog lovers from around the world, I am fully aware that the convenience of kibble, and the cost, play a role in why some people choose kibble over raw.

          However, if what I wrote above makes sense to you and you feel ready, I can say with confidence that your dog will live a healthier and longer life on average, and your vet visits will be less frequent.

          Also making either raw or cooked food can be cost-effective, especially if you include the savings on veterinary care.

          I know of no human doctors who would recommend processed food instead of wholesome natural food and I hope that one day the same will become true in veterinary medicine. You and your beloved dog can be a part of this change by sharing this article with your friends.

          How to prepare healthy natural dog food

          For more info on how to prepare healthy natural dog food recipes here are two important links:

            1. A quick 15-minute course about how to feed a Raw and Cooked Diet for Dogs

            2. The Healthy Dog Food Recipe Maker – a free tool to help you create healthy and balanced recipes, including quantity to feed, and what ingredients are good and safe for your dog.
          Watch my Facebook Live on this same topic here: 


          Or if you prefer to listen - check out the podcast!

          © Dr. Peter Dobias, DVM 

          About the author

          Dr. Peter Dobias, DVM is an Integrative veterinarian, nutritionist and creator of natural supplements for dogs and people. Helping you and your dog prevent disease, treat nutritional deficiencies, and enjoy happier, healthier, and longer lives together.

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