Calcium Phosphorus Ratio in Giant Breed Puppy Food

Years ago when I started raising big dogs myself, I remember being very confused about the Calcium Phosphorus ratio in giant breed puppy food.

What does this ratio mean, and why is it important?

This post will simplify calcium/phosphorus ratios in dog food and with science and information from legitimate sources. Let’s dig in.

What is a Calcium Phosphorus Ratio?

This is the relationship of the amount of calcium and phosphorus (CA/PH) to each other.

For example, if I have 10 grams of calcium and 10 grams of phosphorus, I have a 1 : 1 ratio.

Or if I have 1.1 % calcium and 1.1% phosphorus, that is also a 1 : 1 ratio.

In other words, for every bit of calcium, there is an equal amount of phosphorus.

It is more common to see ratios where there is slightly less phosphorus than calcium, which might look like this:

Calcium 1.1%
Phosphorus .9%
CA/PH ratio = 1.2 : 1

Depending on how much calcium and phosphorus the dog food manufacturer has in the food, this ratio will vary.

I’ve even seen it where there was more phosphorus than calcium!

What is a Good Calcium Phosphorus Ratio for Giant Breed Puppy Food?

Legitimate sources indicate that the ideal ratio for calcium to phosphorus in large and giant breed foods is for both values to closely match, with calcium always being the slightly larger value.

A 1 : 1 ratio of CA to PH is ideal.

If we look towards dog food companies that put millions of dollars into research and feeding trials, we consistently see a CA/PH ratio of around 1.2 : 1.

That is basically as close as it gets, and the research food companies (Purina, Royal Canin, Hill’s, Eukanuba) are very consistent about this.

Unfortunately, however, the science is not yet fully conclusive. Many large breed puppy foods that carry the AAFCO large breed growth statement have calcium/phosphorus ratios as high as 1.8 : 1.

Because the large research dog food companies who have multiple highly qualified nutritionists on staff reliably stick to the lower end (1.2 : 1), we’re going to follow their lead.

It’s important to note that many foods DO exceed what the NRC considers to be a safe upper limit of 4.5g of calcium per 1000kCal. The CA/PH ratio alone is not the only consideration.

For this reason, we believe that the AAFCO large breed growth statement is not enough information alone to choose a safe food for a growing giant breed puppy.

Considerations When Choosing a Large or Giant Breed Puppy Food

By eliminating all foods that fall outside of what we know to be a safe range (1 : 1 or 1.2 : 1), we can narrow our choices down dramatically.

While many giant breed puppies are raised on foods with CA/PH ratios of 1.4 : 1 or even farther apart, there is no reason to choose those foods when we have other options that are closer to the 1 : 1 range.

Here are some other things I personally look for when feeding a giant puppy:

  • Was the food formulated by a qualified nutritionist (somebody with a PhD in Animal Nutrition or a DACVN Veterinary Nutritionist), who is directly employed by the company for that purpose?
  • Has the food undergone AAFCO feeding trials, proving its legitimacy and safety not just on paper, but in real life too?
  • Is the calcium level itself within an acceptable range (ideally around 1.2%, no more than 1.4%)?
  • Does the food have the AAFCO large breed growth statement?

If you are ready to look at brands and choose a food with safe calcium and phosphorus levels for your Borzoi, Great Dane, Mastiff, or Wolfhound puppy, check out our Giant Breed Puppy Food search tool. It has over 600 brands to search and will quickly allow you to narrow it down to the safest and most nutritious options for your pet.

The Giant Breed Puppy Foods Search Tool

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