Home » Plants & Animals » Young Horses/Foals » The Great Age Debate

The Great Age Debate

© Sally White

Thoroughbred racehorses are asked to carry a jockey at high speed, for long distances, in one of the most strenuous equine sports there is, at the age of two. Yet Lipizzaner stallions in Vienna, who carry out leaps and pirouettes requiring the greatest of suppleness and concentration, are left in their fields until they reach the age of five. Which is right?

The debate over what age to start riding a young horse is a fierce one in the horsey world, and it raises tempers faster than you can say "physically mature". Which is what the whole debate hinges on - for opinions differ widely as to when a horse is sufficiently developed enough to take the weight of a human being.

As your horse grows, his bones and joints get stronger through the fusion of his growth plates - flexible areas which, at birth, are separated by a layer of crushable cartilage and allow the horse's bones to lengthen and grow. There's a widely-held belief that these growth plates only exist in a horse's knee: but in fact, there are growth plates almost everywhere that a horse has joints. They are all weak points, and unable to bear much weight, until they fuse - that is, the cartilage disappears and they join together in one strong unit.

So the horse's strength - his physical maturity - is determined by when this turning point is reached. This happens at differing rates in different areas of the body - and some growth plates in a horse's body have still not fused by the time he is six.

Here's what's happening to your horse's skeletal structure at different times in its life, as outlined by the celebrated vet and conformation specialist, Dr Deb Bennett (who runs the Equestrian Training website):

At the age of 1 year:

the horse's pasterns have fused

At 18 months:

his cannon bones are mature

At 30 months (2.5 yrs):

he now has stronger - but not entirely mature - knees (the small bones have fused), and his fetlock joints are mature

At 3 years:

the weight-bearing area at the base of the knees is fused, as well as his hindleg between hock and stifle

At 3-and-a-half:

the highest part of his foreleg, the humerus, is fused, as are parts of his femur, the area of his hindleg between stifle and hip

At 4 years:

the shoulder is fused, and the hocks and pelvis are now mature

At 5-and-a-half:

the growth plates over the centrum, which allows the spine to flex, become fused