Calcium for Dogs

Calcium is one of the most important nutrients in a dog's development. Together with phosphorus it makes up most of their bone mass, that is, the skeleton, but it is also essential for the nervous system to work properly, as well as the muscular and hormonal systems.

There are plenty of natural foods rich in calcium for dogs, although if your dog eats prepared products such as commercial food, the calcium is probably already added to its composition and no supplement is needed.

Let's look at what normal calcium levels are for a dog, which dogs need more calcium, which foods are most advisable and how to know whether our dog needs calcium or has too much calcium in their diet. Ready?

What Role Does Calcium Play in Dogs?

Although the main function commonly associated with calcium is forming bones, this is only one of the many it has. It has functions ranging from fertilisation to nerve impulses, which is why the mechanisms for regulating calcium are extremely detailed and delicate. What is more, its intake has to be in perfect balance with phosphorus, such that if this balance is broken — whether from a shortfall of one, an excess of the other, or both — it will have consequences for our dog's health.

To measure this balance there is a parameter called the Calcium/Phosphorus ratio, essentially a division between the amount of calcium and the amount of phosphorus, expressed as a fraction. The ideal is 1/1 (one part calcium for every part phosphorus).

It is hugely involved in fertilisation and the spread of intracellular signals. Alongside other ions such as sodium and potassium, it maintains the action potential of neurons, which allows every kind of nerve impulse to be transmitted. Muscle contraction is also aided by this mineral, a function that includes the contraction of the heart.

How Is the Amount of Calcium in the Body Regulated?

Given all the functions we have covered, plus all the ones still to cover, it matters a great deal to know how calcium manages to reach everywhere in the right amount so the body can keep working.

Calcium in the body is found in 2 different compartments:

1. 99% in the bones.
2. 1% in the blood.

These two compartments are not static; calcium moves from one to the other and back again. This means that even once our bones have finished growing they can carry on renewing themselves, and that if there is a temporary shortfall of calcium in the diet, the bones can serve as a reserve to draw on.

The body also has a gland called the parathyroid, which secretes hormones that raise (parathyroid hormone) or lower (calcitonin) blood calcium. Vitamin D is heavily involved in this process. Once activated, it raises blood calcium by drawing it from the bones and increasing its absorption in the gut.

Calcium During a Dog's Growth

Being part of bone mass, it is the mineral that tends to worry people most when it comes to the life stage covering our animal's first year: growth.

There are two fairly widespread beliefs:

1. A great deal of calcium is needed to grow strong bones.
2. The more calcium my animal eats, the more they will grow.

As for the first, good bone condition is linked to growth, which is certainly true. On the other hand, a greater amount of calcium is linked to stronger bones, but this needs qualifying.

As we will see further on, it is true that dogs need more calcium during growth, practically double what they need as adults. The problem is that these are such small amounts compared with the needs for other nutrients that it is very easy to overdo it and cause hypercalcaemia.

As for the second claim, it starts from an entirely mistaken premise: wanting our animal to grow to their absolute maximum. Growth is a process shaped by a great many factors, both genetic and external, and for the animal to have a good quality adult life, it has to happen at an optimal pace. That is, neither too fast nor too slow. To achieve that pace, it matters to follow nutritional recommendations and neither fall short nor overdo it.

How Much Calcium Does a Dog Need to Eat a Day?

Dogs' calcium needs are relatively low: 0.6% calcium daily in the diet is more than enough under normal conditions. During growth these needs rise to 1%, and during nursing and late pregnancy, to between 0.75 and 1.5%.

They do not need to eat calcium every day; even so, if they do so in the right doses, nothing bad happens either. The right question is how much calcium a dog needs in their diet overall, since if they get plenty of calcium one day and none for the next two or three, their calcium levels will stay normal thanks to the mechanisms we have described.

In quantitative terms, a puppy needs to eat an average of three hundred and twenty milligrams of calcium daily per kilo of body weight, or 1% of their diet. So if our puppy weighs ten kilos, they will need an average of three grams a day.

An adult dog, on the other hand, does not need such a large amount since their body is fully developed, so an average of one hundred milligrams daily per kilo of body weight is enough (or 0.6% of their diet).

These are the calcium doses for dogs recommended by veterinary bodies; even so, there can be situations where the dog needs more or less than this. For that, a blood test at a vet clinic will be needed.

Pregnant or nursing bitches (already feeding their pups milk) need extra calcium in their diet. So the daily amount of calcium they need is much higher than that of a normal adult dog.

Which Natural Foods Suitable for Dogs Are Rich in Calcium?

As we have seen, calcium metabolism is extremely complex, and its absorption in the gut is shaped by blood and bone calcium levels. If these are normal, less will be absorbed than if they were low.

What is more, the calcium in foods can come in very varied forms that make its absorption easier or harder. It also matters a great deal that it is in balance with the phosphorus in the diet.

There are plenty of natural foods that contain a large amount of highly assimilable calcium for our dogs. Even the water they drink contains calcium, though not in amounts large enough to count as a supplement.

Let's look at which foods contain the most calcium and are suitable for dogs, though the amount to give depends a great deal on the dog's age, size and weight. Remember that some dogs are not used to eating natural foods, so if you have the option of chopping them up, they will be easier for them to digest.

• Meaty bones
• Plain yoghurt
• Fermented cheese
• Fish
• Eggshell

Meaty bones are the soft bones of certain animals such as chicken, very easy for adult dogs to chew and digest. The best bones for dogs are usually those making up the chicken's ribcage and/or the wings.

Even so, puppies cannot chew them, since their adult teeth are not yet fully developed, so it is advisable to chop up the wing tips for them, which are softer and easier to chew.

Plain yoghurt is also an excellent source of calcium; milk is not good for dogs because it contains lactose, but in yoghurt the lactose has been fermented, so it does not harm them.

The same goes for fermented cheese, which contains no lactose, making it an excellent source of calcium for our dog. Even so, cheese is also very fatty, so we need to be careful with the amount we give them so it does not cause digestive problems.

Fish, beyond containing a large amount of vitamins and minerals, contains a good dose of calcium. Ideal as a natural food supplement, tuna, salmon and sardines specifically: Can my dog eat sardines?

Eggshell also has a large amount of calcium, though we personally do not recommend it. Raw, it can carry salmonella, which is very harmful to our dog. And cooked, we have to chop it up and turn it almost into powder so it agrees with them when eaten. Even so, plenty of dogs do not tolerate eating eggshell, so we recommend using one of the options above instead.

Alternatively, our vet can prescribe calcium tablets for our dog, telling us the right daily dose. This tends to be the simplest option, though obviously it is not a natural one.

Excess or Deficiency of Calcium — How to Spot It?

The truth is that the only reliable way to know whether our dog has a calcium deficiency or excess is through a blood test at a vet clinic, since these are often symptom-free if the imbalance is mild. This is without doubt the most efficient way to keep our dog's calcium levels within normal values.

Even so, we can know, or at least suspect, that our dog has excess calcium from the appearance of the following symptoms:

• More frequent urination. Increased water intake.
• Loss of appetite. Lethargy.
• Vomiting. Constipation.

On the other hand, hypocalcaemia presents with the following symptoms:

• Muscle stiffness. Vomiting.
• Fever. Spasms.
• Loss of appetite. Weakness.

Another suggestive behaviour can be licking surfaces, though this does not happen in every dog. If your dog eats good-quality kibble (dog food, commercial food…), it almost certainly already contains all the calcium your dog needs to avoid problems of this kind.