Determining mature height
We asked horse training expert Dr. Jessica Jahiel, whose teaching goal is to develop balanced, willing, forward horses and thoughtful riders. More on Jessica

From: Erin

About six months or so ago, I wrote to you about my shire/TB cross yearling - it was regarding his height/growth.

You told me about that great method for determining height, where you measure from the elbow to mid fetlock and then invert the tape to see how many more inches above the wither my horse would grow.

I did that, and at that time, he was 14.2 at most. The tape gave me about 2-3 inches higher. He is now 2 years old and just barely 15 hands. He is out of a 16.0H shire mare with a TB father who I was told was 16.1H, however, I can not find any more information about my horse's father.

I know that horses can grow until they are age 5-6, but are there any exceptions regarding horses who can and do mature very early? I own an extensive library of books on horses and some say they can grow till they are 5-6 yrs. old, and others say that the TB AND the Shire mature early and that if a shire has a small head as a yearling or foal that it means early maturity for that particular horse, and that it should be discriminated against.

When my horse was gelded, my vet didn't believe me about his age. He thought he was much younger than I told him he was until he looked at his teeth.

Then, he had a very serious injury to his pastern joint as a 10 month old. When I brought him back again to the vet. hospital (1 yr. later, as a 2 yr. old), as they told me to, the doctor asked if he was a yearling!!!!

I guess they think he is small for his age. I know that all horses, despite their breed grow at different rates, but when I do your measurement thing from the elbow to the fetlock, now, at two years old; it measures well below the withers. Could he possibly be done growing and matured early????

I have a QH mare who is only 14..3-15.0 max. I am not a small woman, even when I'm thin, I've got a large frame with big, strong bones, but she can carry me no problem! She's such a strong little mare. I ride her english in jumping (she was not suited for dressage, nor would she even think of doing it) :) classes (small schooling shows), and we do so well as she enjoys every fence. My young gelding was to be my dream horse for dressage and after surgery (arthrodesis of the pastern joint), I was hoping he would turn out to be suitable to my size. I am 5 feet 8 inches tall and ideally (when I was younger I weighed 130lbs). I am now 172 but working out 4x per week for him, but mostly for me!!!

There's probably a lot of information in this letter that you don't need. The real question was just "Have you ever seen or known a horse to mature at 2 yrs. of age?

Thanks for listening and responding.

Answer
Hi Erin! First, your young horse probably WILL be an excellent size for you when he is full-grown. He isn't anywhere near mature yet, and he'll fill out over the next few years. Unless you are ALL leg and he grows up to be a very narrow horse, you will probably find that he fits your leg quite well.

I've never seen a horse mature at 2 years of age. It's just not physically possible. TTT -- Things Take Time. A physically mature two-year-old horse would be like a healthy baby born after a three-month pregnancy! I have seen horses that have been fed too much, too early, in an attempt to make them grow faster, and some of those horses have achieved most of their mature HEIGHT by age 2. Generally, though, this happens at the expense of bone quality and joint soundness, so it's not something to try to achieve deliberately -- and even racehorses, which are often pushed to become as large as possible for the yearling sales, generally gain another inch in height by the time they are six or seven.

I can't really predict where your horse will end up, height-wise, especially given the lack of family history. I CAN tell you that it's perfectly possible to cross a 16.0hh mare and a 16.0hh stallion and get offspring of anywhere between 14.2hh and 17.2hh -- I've seen both results.

Here are some thoughts that may help.

Horses can be made to reach their full height earlier than they would normally, but they can't be made to get TALLER than their genetic programming allows.

Small horses grow proportionately -- 5% of a 14.2hh horse's height is a smaller amount than the same 5% of a 16.0hh horse's height. Your horse is probably growing nicely, according to schedule -- but it's his own genetic schedule he's going to follow, not your plans. :-(

I've always had good luck picking foals out of pastures and predicting which ones would become really tall and which ones wouldn't, and here's my secret: I look at their body balance. If a young foal looks like a tiny version of an adult horse, it's probably going to be a small horse when it's full-grown. If a young foal reaches the age of two without having gone through an awkward, gangly stage, it's probably going to be a small horse when it's full-grown. The gangly and awkward ones that first seem to have huge heads and huge joints, then grow up one end at a time, first croup-high, then high in front, then croup-high again, and that go through a stage during which they look long and bony and uncoordinated -- those are the ones that will probably be tall when they are full-grown. This would tie in with your source that mentioned a small head indicating early maturity -- it doesn't mean that the horse will actually be physically mature earlier, you'll still need to wait for the skeleton to finish developing. But I would interpret that statement as meaning that a foal that develops adult proportions very early is a foal that is going to grow up to be a small horse.

When one of my foals (out of a 15.3hh mare, by a 16.2hh stallion) was born looking like a tiny horse, I knew that she wasn't going to be taller than her mother. By the time she was two, she had never had an awkward DAY, and I knew that she might reach 15. 2hh -- or not. She just made it, but not until she was a full seven years old. She was a crossbred and could just as easily have been taller than either parent at maturity -- but she wasn't programmed that way. And she's a very good mare. :-)

Your horse may well be 15.2hh when he's fully mature. His height won't matter as much as his overall build and his movement and the size of his barrel -- if he moves well and fits your leg, you may have your ideal dressage horse. I hope so. Good luck, and keep me posted!

Sincerely, Jessica

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Copyright © 2000. Jessica Jahiel, Holistic Horsemanship® The preceding letter was reprinted, with Dr. Jahiel's permission, from HORSE-SENSE, Jessica Jahiel's HORSE-SENSE Newsletter online at www.horse-sense.org. More information about Jessica Jahiel, Ph.D., Author, Clinician, and Lecturer is available at www.prairienet.org/jjahiel/. You may email Dr. Jahiel at jjahiel@prairienet.org or call (217) 684-2570

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