Last Updated on March 10, 2022
If you look at a newborn foal, you might be amazed at how long their bones are! But to learn how horses grow, we need to look at a horse bone growth chart. This chart tells us the stage at which each bone in a horse’s body matures as a young horse turns into an adult.
How Do Horses Grow?
When a foal is born, it has an immature skeletal system that needs time to grow and develop. At this stage, the bones are already remarkably well developed, which is why a newborn foal can stand and run within hours of birth. However, these bones are not as strong as adult bones and are not able to carry much weight.
For this reason, a newborn foal has a very lightweight body, and as the foal grows the bones will strengthen to support this weight. This is a long, slow process that takes several years.
So, what happens as a bone grows? The way this happens depends on the type of bone. There are two main groups of bones in the horse – flat bones, such as the skull and parts of the pelvis, and long bones, such as those in the limbs.
When we are looking at bone growth in horses, it is normally the long bones that are of most interest, as they are more susceptible to developmental abnormalities. These bones grow from a cartilage template, that gradually turns into bone. At each end of the bone is a growth plate; this is where the bone can extend in length.
When the growth plate closes then the bone can no longer grow in length but may need more time to reach full strength and maturity. For this reason, it is very important to be cautious when exercising young horses. If subjected to too much pressure, the bones may develop abnormally, leading to problems later in life.
What Is A Horse Bone Growth Chart?
A horse bone growth chart tells us at what stage each of the bones in the horses’ skeletal system is fully mature. This means that the growth plate of the bone is fully closed and that it has reached the maximum levels of strength.
The interesting thing about how the bones of a horse mature are that they start from the ground upwards! The bones in the lower limb are almost full-size when the foal is born, and quickly grow and mature. The highest bones, such as those along the spine, take much longer.
It is important that horse owners and trainers are aware of how a horse grows so that we can avoid subjecting them to too much physical stress while they are young. It is not uncommon for horses to be broken to ride at 3 or 4 years old, or even as young as 2 in the case of Thoroughbred racehorses. At this stage, there are many bones in the horses’ skeletal system that are not fully developed and are at a high risk of injury.
The Horse Bone Growth Chart
So, let’s take a look at the skeletal system from the ground upwards, and see at what stage each bone develops:
- Distal phalanx – mature at birth
- Mid & proximal phalanx – 9-12 months
- Metacarpal and metatarsal bones – 18 months
- Carpus – 18-24 months
- Radius, ulna, humerus, and scapula – 3 to 3.5 years
- Tarsus & tibia – 3 to 3.5 years
- Femur – 3-4 years
- Pelvis – 5 years
- Vertebral column – 5.5 to 8 years
It is incredible to see that some horses will not be fully physically mature until they are 8 years of age! By this time, many horses will have been in ridden work for 4 years or more. Some of the ridden exercises we use horses for, such as jumping, roping, or top-level dressage, can put intense pressure on the skeletal system and cause bone developmental abnormalities in a young horse.
If you are working with a young horse, it is important to take into account his physical immaturity, even if he is grown to his full height. The correct diet must also be fed to encourage steady bone development, rather than a period of rapid growth.
Horse Bone Growth Chart Summary
So, as we have learned, a horse bone growth chart shows us the stages at which each of the bones in the skeletal system of a horse becomes fully mature. This process takes several years, as the bones extend in length and become stronger. Subjecting a young horse to intense exercise before the skeletal system is fully mature can lead to lameness problems later in life.
We’d love to hear your thoughts about the horse bone growth chart! Do you have a question about how the skeletal system of a young horse develops? Or perhaps you know of a horse that had a bone growth abnormality? Leave a comment below and we’ll get back to you!
How Do Horses Develop Bones?
Horses bones develop over a very long period of time. This process starts in the womb, when the foetus develops an immature skeletal system. When a foal is born, it has well-developed bones that then grow as the foal matures.
At What Age Do Horses Growth Plates Close?
The growth plates of horses bones all close at different stages of the horses life. Some are already closed at birth, while others will not close for several years.
What Age Do Horses Bones Mature?
The bones on a horse grow quickly, but they take several years to mature. The skeletal system of a horse is not mature until the horse is between five and eight years old.
What Bone On A Horse Never Grows?
When a foal is born, its skeletal system will grow quickly, but some bones have more growing to do than others. One bone which is almost fully formed at birth is the lowermost bone in the horse's limb, the distal phalanx.
This bone, also known as the coffin bone, has closed growth plates when the foal is born, and does not increase in height. However, this important bone does get larger as the foal matures, as new bone is laid down on the margins of the bone.
Kate Chalmers is a qualified veterinary nurse who has specialized in horse care for the vast majority of her career. She has been around horses since she was a child, starting out riding ponies and helping out at the local stables before going on to college to study Horse Care & Management. She has backed and trained many horses during her lifetime and competed in various equestrian sports at different levels.
After Kate qualified as a veterinary nurse, she provided nursing care to the patients of a large equine veterinary hospital for many years. She then went on to teach horse care and veterinary nursing at one of the top colleges in the country. This has led to an in-depth knowledge of the care needs of horses and their various medical ailments, as well as a life-long passion for educating horse owners on how to provide the best possible care for their four-legged friends.
Kate Chalmers BSc (Hons) CVN, Dip AVN (Equine) Dip HE CVN EVN VN A1 PGCE