What is the ideal calcium level in large breed puppy food?
For many years now, Royal Canin has been advised breeders and owners of large breed puppies against the risk of calcium (Ca) excess in the diet of these puppies. But what does “ excess ” really mean ?
Calcium metabolism in puppies
The way a puppy absorps Ca is twofold: actively and passively. Even if he receives a diet excessively rich in Ca, he will always absorb at least 45 to 50 % of it. This Ca excess then promotes the production of an hypocalcaemic hormon, the calcitonin, that stimulates Ca deposit in the bone tissue, and prevents from Ca mobilization from the bones. The problem is: during the growth, there is a high turn-over of the bone tissue; if the physiological exchanges between bone and blood are restrained, the bone structure becomes abnormal, leading to possible distortions.
What are the available data today ?
The quantity of Ca ingested depends on the concentration of Ca in the diet, but also on the energetic consumption. As the rationing is based first on the energetic requirements of the puppy, it sounds logical to calculate first how many grams of Ca are absorbed by a puppy when he consumes the equivalent of 1000 kcal.
Advisable minimum levels
Some dutch studies performed on Great Danes puppies have shown that above 1,5 g Ca / 1000 kcal (or 0,55 % Ca for 3560 kcal), a reduction of the bone mineralization is observed, and fractures may happen spontaneously. Small breed puppies (here small Poodles) are really less demanding, as they tolerate without any problem a diet with 0,33 % Ca on DM only. It is then false to say that large breed puppies has got a Ca requirement inferior towards small breed puppies. What is true about energy is not true concerning calcium.
Advisable maximum levels
The same authors have induced growth delays and many skeleton disorders in Great Danes puppies, by feeding them a diet containing 9,1 g Ca / 1000 kcal. Iams recently sponsored a similar trial and they declare they have observed troubles with diets containing even less Ca: 6,5 g Ca / 1000 kcal or 2,7 % Ca on crude. In this experiment (like in the previous one quoted), puppies were fed ad libitum during 2 periods of 30 mn per day: we can then suppose that their Ca intake was over what it should have been.
What are the practical applications of these studies
>From the experiments described above, it is not possible to deduce a single ideal Ca content, acceptable for all puppies. We can just estimate a safe bracket, between minimum and maximum limits. It is exactly what has done the Association of American Feed Control Officials (AAFCO), whose recommendations are respected by all the petfood manufacturers. Today AAFCO advises for puppy food:
1-2,5 % of Ca / DM (or 0,9-2,2 % on crude), i.e 2,9 to 7,1 g /1000 kcal.
It has been said that a high Ca- product was a low-quality one, because it was the sign it contained too much of meat and bone meals, poorly digestible. This criticism cannot be made towards Maxi Junior: in this product, we must add Ca carbonate to reach the Ca level that is guaranteed.
Our competitors have chosen to adopt a lower Ca level: Hill’s Growth for Large Breed brings 2,6 g Ca / 1000 kcal (0,9 %), and Eukanuba Large Breed only brings 1,9 g Ca / 1000 kcal (0,8 %). With such a low level of Ca, this Eukanuba product is situated in a critical area. Of course, it is possible to make large breed puppies grow up correctly with such a diet, but it is also risky. Ca assimilation might be disturbed by various factors, depending both on the food itself and on the puppy: Ca absorption can be inhibited by phosphore, oxalate, fibers, and the digestive ability is sometimes upset for pathological reasons, stress, parasitism, etc…
It is our job to make our best to inform owners of large breed puppies about the dangers coming from:
1/ hazardous supplementation with mineral and vitaminic preparations
2/ overfeeding during growth, which is an aggravating risk factor for diseases such as hip dysplasia or osteochondrosis.
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