How much is too much calcium for dogs? A Step-by-Step Guide

How Much Calcium Should a Dog Receive?

Based on the recommendations from The Association of American Feed Control (AAFCO), adult dogs should receive about 1.25 grams of calcium for every 1,000 calories they consume. This number changes slightly based on their overall size and weight but is a safe guideline to use if you’re unsure where to start.

There are several supplements and human foods that are safe for dogs to consume and boost their calcium levels. Many of these foods are the ones we eat when trying to increase the calcium in our own bodies, but you should always confirm that they are a safe choice from your vet. Professionals will be able to guide you accurately and make recommendations that you may not have considered before.

How To Add Calcium To Homemade Foods

Kibble and most commercial pet foods are formulated on a dry matter basis (how much of a nutrient remains when the water weight of the food is removed). This works well for kibble because most kibble is the same … but raw and home cooked diets need to be formulated on a caloric basis because they contain a wide variety of calories from fat. Simply stated, this means “How much calcium is in 1,000 calories of food?”

Now, it would be simple and easy to say “Add 1 teaspoon of calcium supplement to 1 pound of food” … but fat contains twice as many calories per pound as protein and carbohydrate. This means the amount of food your dog eats every day depends on the fat content. So fresh diets need to be analyzed by calories, not dry matter.

With that said, here’s a breakdown of each calcium source and how well it will balance diets with various fat levels. We don’t recommend feeding a diet that’s over 20% fat … this would contain twice as much fat as protein and is not recommended for long-term health. Fat is relatively devoid of vitamins and minerals, so it’s important to feed no more than 20% fat without veterinary guidance. This is especially important for puppies and pregnant dogs because they will not be able to get enough nutrition from their food unless they eat too many calories. Remember, much of your dog’s meal is water weight, so a food that’s 20% fat will only contain about 10% protein. Ideally, you’ll want to feed 10% fat and certainly no more than 15% fat.

When You DON’T Need to Add Calcium to Your Dog’s Food

Never add calcium to commercial diets that are “complete and balanced” – these already contain the right amount of calcium! Adding calcium to a “complete and balanced” diet would be particularly dangerous for large-breed puppies.

However, most homemade diets require added calcium with a few notable exceptions. DO NOT add calcium to a home-prepared diet if:

You feed a raw diet that includes raw meaty bones (RMBs) — parts such as chicken and turkey necks where the bone is fully consumed. Bones are high in calcium and phosphorus; there’s no need to add calcium to a diet that includes at least 25 to 30 percent RMBs.

You use a supplement that is especially designed to complete and balance a homemade diet, such as those made by Balance IT and Just Food For Dogs.

You use a dog food “base mix,” such as those made by The Honest Kitchen and Sojo’s, that you combine with your own added protein source according to the product directions.

When using supplements or base mixes that promise to complete a homemade diet, make certain that the product includes a complete nutritional analysis showing appropriate amounts of calcium. Don’t accept the verbal assurances of the company’s owners or representatives, or those of pet food store employees; if they can’t or won’t provide you with complete nutritional analyses of their products, we would not rely on those products for anything more than an occasional meal.

With very few exceptions (see “When You Don’t Need to Add Calcium,” above), you need to add calcium to your dog’s homemade diet.

Calcium guidelines can be determined in several different ways, including the body weight of the dog, the dry matter percentage of the food, and the calories that the dog needs. Each has its own complications:

Small dogs eat more and have higher nutritional needs for their weight than large dogs do, so you can’t use linear guidelines such as “give x amount per 10 pounds of body weight.” Any time you see linear feeding instructions, it’s a red flag that whoever is giving the instructions does not understand nutrition.

The amount of moisture (water) in food can vary from about 10 percent or less in dry foods (kibble, dehydrated, freeze-dried) to 80 per percent or more in wet foods (canned, fresh, frozen, raw, cooked). You must convert the “as fed” food weight to dry matter (DM) in order to give guidelines based on how much food is fed. Dry matter percentages won’t change much when you convert from “as fed” for dry foods, but are usually three to five times as much as the “as fed” percentage for wet foods. Also, because we feed dogs less of high-fat, calorie-dense foods, adjustments need to be made for foods with more than 4,000 kcal/kg DM.

Calculating nutritional requirements based on the number of calories your dog needs is the simplest method, but comes with some warnings as well. Caloric needs will vary based on your dog’s activity level, metabolism, and more. The right amount to feed will also be affected by how many calories your dog gets from treats, chews, leftovers, and other sources. In particular, inactive dogs who eat less food for their weight than would be expected should get most of their calories from a balanced diet in order to avoid nutritional deficiencies.

The National Research Council (NRC) issued updated nutritional guidelines for dogs in 2006. They recommend feeding adult dogs at least 1 mg of calcium per Calorie (kcal), which is the same as 1 gram (1,000 mg) per 1,000 kcal (Mcal).

The nutritional guidelines published by the Association of American Feed Control Officials (AAFCO), which were finally modified in 2016 to reflect the latest NRC recommendations, increased this to 1.25 mg calcium/kcal (1.25 grams/Mcal).

On a dry matter basis, that’s 4 to 5 grams of calcium per kilogram of food on a dry matter basis, or 0.4 to 0.5 percent DM.

One other factor affects how much calcium your dog needs: phosphorus. There should always be at least as much calcium as phosphorus in the diet, up to twice as much for healthy dogs (or three times as much for dogs with kidney disease).

Most homemade diets that I’ve looked at have between 0.5 and 1.25 mg phosphorus per kcal, so giving 1.25 mg calcium per kcal will provide most dogs with an appropriate amount of calcium and a proper calcium:phosphorus ratio.

You will need to know how many calories your dog is likely to need, based on his ideal weight – not his actual weight. See Table I on the next page for the approximate amounts of calcium to add to homemade diets for dogs of various sizes and various activity levels in order to provide 1.25 mg of calcium per kcal. While nutrient needs don’t vary by activity level, dogs who eat more food need more calcium in order to balance out the amount of phosphorus in the diet.

At minimum, give the lowest amount of calcium shown for your dog’s ideal weight, even if you find that you need to feed fewer calories than shown to keep your dog at a proper, lean weight. If you must feed a lot less to help your dog lose weight or prevent your dog from gaining unwanted weight, it’s time to cut back on the number of calories your dog gets from other sources.

The amount of calcium you give does not need to be exact. It’s fine to give a little less or a little more calcium than shown. Most commercial diets for adult dogs that I’ve looked at have between 2 and 3 mg of calcium per kcal (diets designed for puppies or for “all life stages” will have even more). These diets also have an equivalently higher amount of phosphorus.

If you feed a diet that is part commercial, part homemade, adjust the calcium amounts shown in Table I appropriately. For example, if you feed half homemade, give half the amount of calcium shown.

All of these guidelines are for adult dogs only. Puppies are trickier. NRC and AAFCO agree that puppies need at least 3 mg of calcium per Calorie (three times the amount of calcium that adult dogs need on a caloric basis).

The maximum amount of calcium that puppies should get is 4.5 mg per kcal (4.5 g/Mcal). It’s especially important not to give too much calcium to large-breed puppies during their first six months, as they are the group most likely to develop bone and joint abnormalities when given the wrong amount of calcium and phosphorus.

Puppies also need more phosphorus than adult dogs do. Never add plain calcium to a puppy’s homemade diet. Puppies need bone meal or some other type of supplement that provides both calcium and phosphorus, in order to provide the correct amount and ratio of calcium to phosphorus.

Calcium and dogs | A vital nutrient to know

Calcium is an essential mineral critical to many functions in the puppy, and the intake of the correct amount of calcium is key. Too little calcium could lead to rickets or stress fractures, but too much calcium could result in skeletal malformations and secondary nutrient deficiencies.

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