This disease is much less frequent in puppies than in cats, due to certain insalubrious dietary habits of the latter (consumption of too much liver). In dogs, vitamin A overdose is usually due to daily feeding of cod liver oil, which contains about 2000 International Units of vitamin A per gram! Excess vitamin A blocks bone formation and causes shortening of the long bones, as well as bone deformation. These effects are usually irreversible.
Various joint diseases arising in growing puppies are grouped together under the general heading "osteochondroses." These diseases affect mainly large-breed puppies and are marked by hypertrophy of the joint cartilage, causing pain, joint deformities, carpus curvus, etc. Chronic, painful limping causes the joint cartilage to become fissured (the classic case of this is seen in the shoulder of the Labrador
In such cases, the main aggravating factor, other than extreme calcium overdose, is excess food, which causes early excess weight gain. Even a perfectly balanced food can quickly lead to excess weight if too much is given, and the mechanical effects on the still-growing joints and cartilaginous structures will not take long to appear. Such overfeeding may be unintentional on the part of the owner,
if the food is too appetizing and the puppy begs continually (this is consistently true of moist commercial food, and generally true of foods that are too fat), or
when the food's energy content is not properly evaluated. Since highly-digestible high-end dry foods have been put on the market, the traditional model for evaluation, "3.5-3.5-8.5" (3.5 kcal of metabolizable energy per gram of proteins and starch, and 8.5 kcal per gram of fat) has become a "4-4-9" model, since the nutrients are better used by the animal. Such food can cause a 20-kg puppy halfway through the growth stage to deposit 20 to 25 grams per day of useless and harmful body fat.
In such cases, and independently of any surgical treatment that might eventually become necessary, the puppy's feeding program should be revised. First, the type of food should be changed, respecting the nutritional balance defined elsewhere. By far the most effective solution appears to be the use of complete dry foods adapted for breed size. As far as quantity is concerned, a very strict program should be followed, including these steps:
Stick strictly to the portion size prescribed by the veterinarian or suggested by the manufacturer. If the puppy is too large for its age, feed it 75% of this amount for three or four weeks.
Do not feed the puppy anything else.