After several hours of birth the colt can follow the mare. But the bones of the baby are not formed yet, they resemble cartilage tissue.

The colt grows; gradually more and more calcium is concentrated in the bones.

The ordinary anatomic textbook says: “Before the bone stops growing in the length (when the animal becomes grown-up), between the epiphysis and diaphysis the gristle layer remains, it’s called metaphyseal cartilage.

From both sides it’s surrounded by subhondral bone plate. After the birth of the animal metaphyseal cartilages dradually acquire diametrical structure, become thinner, and in the end of growing they are replaced by bone stock – the border between the epiphysis and diaphisis disappears.

Subhondral bone plate of metaphyseal cartilage also disappears.

Appearing of centers of ossification and sinostosys depends on biomechanical load that the bone undergoes.

So every bone has its own deadline of ossification and sinostosys, which depends on species, sex, and age, keeping and feeding.

According to this deadlines veterinarian determines the degree of ripeness and the age of young animals”.

Period of synostosis of skeleton, years:

Axial skeleton: 
Skull - 3-4 
Inside all the spines - 5 
Sacral bone - 10

Skeleton of extremity: 
Free extremities - 3- 3,5 
Pelvic girdle -4-4,5 
symphysis -6

- The horse can’t carry out any kind of physical activity till 3-4 years (including lunging);

- The man can ride the horse only for short period starting from 4-4,5;

- The horse can be in full collection only from 6 years.

- Serious physical activity like (ex. School jumps) can be allowed only after 10 years.

Humans who know neither anatomy nor physiology of the horse, tell about “precocious” breeds. They tell that such horses are ready for breaking in earlier then others. But according to them, teeth of such horses should grow earlier if their organism grows earlier.

Anatomy says, that growing of teeth and bones are interrelated. Teeth of “the precocious” breeds grow up at the same time as of “the late precocious”.

This peculiarity helps to define the age of an animal. So it’s obvious, that both terms “precocious” and “late precocious” are thought of by false specialists.

This idea was caught by horse-breeders, as you know, to sell broken in two-year horse is easier then not broken in 4 year horse.

Moreover, bones (and total weight) of precocious breeds grow in length earlier, but ossify at the same time. So bones are not ready for such a hard job, but they have to endure this. One more think we have to remember is joints, they carry out excess weight of the organism. So horses of this kind are to be broken in even later, they are more particular about the conditions of growing and feeding.

If you buy an early broken in horse, you should remember: 
- such horse will always be underdeveloped: genetic peculiarities won’t develop properly (ex. height); 
- If a horse worked at full stretch, it will never show its best qualities (won’t be strong, fast, energetic and etc.). 
- It’s for sure that a horse will become invalid, instead of being healthy and happy, because its joints endured very hard job. 
- From the youth a horse worked at full stretch, so its life becomes shorter.

This problem becomes more evident in equestrian sport. Normally at the age of 10-15 the horse only starts acquiring his best qualities, but in reality sport martyrs become incurable invalids. When at competitions of international level we can see horses of 10-15 years, everything seems to be all right. But only veterinarians and sportsmen know the true value of such starts. Veterinarians cure, give injections, anesthetize, and when nothing helps from the constant limping, they cut nerves in the distant parts of the legs. Such horse doesn’t feel pain, he doesn’t limp any more, but joints become totally destroyed. After the competition a horse-holder spends all night with the horse making baths, lotions, rubbing, massage and etc. All this are made so next day the horse will be able to go out from the stable. Normally horses live 30-40 years, sport horses live till 15-20 at the same time they are invalids. Of course, lots of things kill horses in sport, but breaking in takes the first place in destroying musculoskeletal system.

Usually if you decided on the breaking in question, next one would appear: “If the horse was free till the age of 4, how it will treat the fact to be ridden?” But before one is going to ride the horse, he should train his horse on the ground. Till 4 it’s just general physical and mental development, the collection and school elements follow. Collection is to be the natural position. If a horse isn’t collected, the rider destroys its back. So when you teach your horse to collect, at the same time you prepare its back for the excess weight. When the horse becomes ready to except you on its back, you’ll become essential part of the lesson full of pleasure. If a man is on the right, on the left, in front, behind and then on the back, a horse should treat it as a part of a lesson. When a horse is taught to work on the ground, you’ll need only 5-10 lessons to teach him to carry saddle and excess weight. Then you saddle him and ask to do something that he already knows. And performing well-known exercise a horse will treat it as a continuation of a lesson. It won’t be stressful. Moreover the complication (the rider) of the well-known element only will raise the interest. If a horse under with the rider performs an exercise worse then without him, it means that preliminary training was not good enough. First you teach your horse in hand, then at liberty you make an exercise perfect. Only after first two steps you can ask an element from the saddle. Such training allows making an element in the saddle better. The main thing is that comparing to traditional breaking in a horse doesn’t get physical and physical traumas.

Amazing article!