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Skeletal Maturity in Horses: Growth Plate Ossification and Age Considerations

Updated: Jan 17


Understanding the process of skeletal maturity in horses is crucial for appropriate management, training and care. Skeletal maturity refers to the point at which a horse’s bones have fully developed and growth plates have ossified. In this, the second part of our blog about young horses, we explore the age at which horses generally reach skeletal maturity and the timeline of growth plate closure in different anatomical regions.

Skeletal maturity in horses signifies the completion of bone growth and the closure of growth plates. It is important to not that skeletal maturity doesn’t necessarily mean the horse has stopped growing in all aspects, as soft tissue and muscle development may continue. The age at which horses reach skeletal maturity varies depending on a number of factors including breed and genetics.

Most horses reach skeletal maturity between the ages of four and six years. However, it is essential to assess individual horses based on their development rather than relying solely on their age.

There is a whole chapter about skeletal maturity in Posture and Performance where, as well as illustrating the age of growth plate ossification, Gillian discusses starting young horses and management suggestions for promoting future health, comfort and performance.

Growth Plate Ossification and Closure

Growth plates are areas of cartilage located near the ends of long bones. They play a crucial role in bone growth and elongation. As a horse matures, these growth plates gradually ossify and close, indicating the end of longitudinal bone growth. The timing of growth plate closure varies between different anatomical regions in the horse’ body.


The growth plates in the distal radius and ulna, which make up the forearm typically close around 9 to 12 months of age.

Cannon Bone

The growth plates in the cannon bones (metacarpals and metatarsals) generally close between 12 and 18 months.

Knee and Hock

These joints, specifically in the proximal metacarpal and tarsal regions, typically close at around 18 to 24 months of age.


The proximal femur and tibia (stifle) usually close between 24 and 30 months.


The growth plates in the vertebrae continue to ossify and close gradually, continuing until the horse is around five to six years old.

Consider each horse as an individual

It’s important that all horses are individuals meaning age ranges for growth plate closures may vary. Environmental factors, nutrition, overall health and training can all have an influence on the timing of growth plate closure.

Understanding the age horses reach skeletal maturity and growth plate maturity helps us to ensure the horse has appropriate management, training and care. However, it is important to evaluate each horse on an individual basis and tailor their management accordingly.

Skeletal Maturity and Exercises for Young Horses is an on-demand webinar that looks at how youngsters, regardless of conformation or type, develop both muscularly and skeletally.

Gillian compares skeletons with both open and closed growth plates and looks at different activities and exercises to help prepare young horses for future ridden work.

Having an understanding of skeletal maturity is key to developing a happy, healthy, posturally strong horse.

There's a fantastic opportunity to learn a lot more on this subject as Growth and Development is the focus for our 2024 conference. This two-day conference (17 -18 February 2024) is the perfect opportunity to immerse yourself in all things equestrian. You will be treated to a packed timetable of presentations from experts who will be discussing the latest scientific information on topics relating to young horses such as starting and training, muscular, neurological and skeletal developmental diseases.

Over the two days, we will also discuss the topic of growth and development relating to personal and professional development, equestrian sports, standards within the equine world, training and competing, and much more. It really is a conference not to be missed!

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