I am attaching
an article below by Dr. Deb Bennett that you may have read before.
But if you have not it is well worth your time and education.
I will pass along articles that I feel will be helpful and useful
for your own review. Enjoy the article and please pass it on.
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Deb Bennett, Ph.D.
TIMING AND RATE OF SKELETAL MATURATION IN HORSES,
With Comments on Starting Colts and the State of the Industry
One of the
most widely-read and widely-requested pieces of information contained
in our ESI Website has been the following article which we familiarly
refer to as "the Ranger piece." By 2005, with our permission this
article has been re-printed in more than 75 magazines and riding-club
newsletters in countries as far away as South Africa, Scotland,
and New Zealand. Without our permission it has also been posted
on about a gazillion websites and "boards", and, I am sure – one
way or another -- read by many thousands of people.
posted on December 14th, 2001 as part of the old "conformation
analysis" section of our website, it was taken off line in January
of 2004 with the restructuring of the site that we did at that
time. Here we post it again in the belief that you might appreciate
having a downloadable copy, so as to more readily be able to share
it with friends and neighbors whom you think might want or need
to see it.
about "Ranger" arose when an ESI website visitor sent a photo
of her two and a half year-old Tennessee Walker gelding to obtain
my comments. We no longer have the original photo, but an exact
tracing with the analytical marks on it accompanies this article,
along with some other explanatory illustrations which have been
added for this revised re-posting.
I began my
reply to Ranger"s owner with comments on his conformation, but
soon got "sidetracked into the main issue," which is, at bottom,
about how to make the best decision as to when a colt may be started
A General Look at Ranger
thing to note is that as a two and a half year old, Ranger is
a "teenager." He's not mature physically, nor will he be until
he's at least six. Despite a nice development of chest and a fine
long neck, there is that unmistakable lack of length and muscular
fullness to the hindquarters and the little weakness or lack of
arch at the base of the neck that smacks of the gawkiness of subadulthood.
The withers are not as high as they will someday be, either. Note
please however, that I have not said anything about Ranger having
a big head - because he doesn't (compare length of head to length
of neck; a horse's head is not to be considered "large" until
it is longer than the underline of the neck). I like the so-called
"old fashioned" head of the Standardbred, Morgan, Saddlebred,
and Walking Horse. An Arabian head is fine - on an Arabian, but
the Arabian head shape should not be the universal definition
of "good" in heads. Ranger's is an excellent head with sharp bony
definition, a good eye, and a real good expression. There are
also solid reasons, having to do with the proper eruption and
functioning of the teeth, for preferring a straight or slightly
arched head, such as Ranger shows, to certain types of dished
construction, and for preferring a longer face (as measured from
eye to muzzle) to a foreshortened face.
All Horses of All Breeds Mature Skeletally at the Same Rate
Now I want
to discuss the concept of skeletal maturity and deal with that
concept thoroughly. Ranger is not mature, as I said, as a 2 ½
year old. This is not because Ranger is a "slow-maturing" individual
or because he comes from a "slow maturing" breed. There is no
such thing. Let me repeat that: no horse on earth, of any breed,
at any time, is or has ever been mature before the age of six
(plus or minus six months). So, for example, the Quarter Horse
is not an "early maturing" breed - and neither is the Arabian
a "slow maturing" breed. As far as their skeletons go, they are
the same. This information comes, I know, as a shock to many people
who think starting their colt or filly under saddle at age two
is what they ought to be doing. This begs discussion of (1) what
I mean by "mature" and (2) what I mean by "starting".
When is a Horse Skeletally Mature?
everybody has heard of the horse's "growth plates", and commonly
when I ask them, people tell me that the "growth plates" are somewhere
around the horse's knees (actually the ones people mean are located
at the bottom of the radius-ulna bone just above the knee). This
is what gives rise to the saying that, before riding the horse,
it's best to wait "until his knees close" (i.e., until the growth
plates convert from cartilage to bone, fusing the epiphysis or
bone-end to the diaphysis or bone-shaft). What people often don't
realize is that there is a "growth plate" on either end of every
bone behind the skull, and in the case of some bones (like the
pelvis, which has many "corners") there are multiple growth plates.
So do you
then have to wait until all these growth plates convert to bone?
No. But the longer you wait, the safer you'll be. Owners and trainers
need to realize there's a definite, easy-to-remember schedule
of fusion – and then make their decision as to when to ride the
horse based on that rather than on the external appearance of
the horse. For there are some breeds of horse – the Quarter Horse
is the premier among these – which have been bred in such a manner
as to look mature long before they actually are mature. This puts
these horses in jeopardy from people who are either ignorant of
the closure schedule, or more interested in their own schedule
(for futurities or other competition) than they are in the welfare
of the animal.
The Schedule of Growth-Plate Conversion to Bone
of converting the growth plates to bone goes from the bottom of
the animal up. In other words, the lower down toward the hoofs
you look, the earlier the growth plates will have fused; and the
higher up toward the animal's back you look, the later. The growth
plate at the top of the coffin bone (the most distal bone of the
limb) is fused at birth. What that means is that the coffin bones
get no taller after birth (they get much larger around, though,
by another mechanism). That's the first one. In order after that:
pastern - top and bottom between birth and 6 months.
- Long pastern
- top and bottom between 6 months and one year.
bone - top and bottom between 8 months and 1.5 years
- Small bones
of the knee - top and bottom of each, between 1.5 and 2.5 years
of radius-ulna - between 2 and 2.5 years
portion of glenoid notch at top of radius - between 2.5 and
- top and bottom, between 3 and 3.5 years
- glenoid or bottom (weight-bearing) portion – between 3.5 and
- lower portions same as forelimb
- Hock -
this joint is "late" for as low down as it is; growth plates
on the tibial and fibular tarsals don't fuse until the animal
is four (so the hocks are a known "weak point" - even the 18th-century
literature warns against driving young horses in plow or other
deep or sticky footing, or jumping them up into a heavy load,
for danger of spraining their hocks).
- Tibia -
top and bottom, between 3 and 3.5 years
- Femur -
bottom, between 3 and 3.5 years; neck, between 2.5 and 3 years;
major and 3rd trochanters, between 2.5 and 3 years Pelvis -
growth plates on the points of hip, peak of croup (tubera sacrale),
and points of buttock (tuber ischii), between 3 and 4 years.
And what do
you think is last? The vertebral column, of course. A normal horse
has 32 vertebrae between the back of the skull and the root of
the dock, and there are several growth plates on each one, the
most important of which is the one capping the centrum. These
do not fuse until the horse is at least 5 ½ years old (and this
figure applies to a small-sized, scrubby, range-raised mare. The
taller your horse and the longer its neck, the later the last
fusions will occur. And for a male - is this a surprise? - you
add six months. So, for example, a 17-hand Thoroughbred or Saddlebred
or Warmblood gelding may not be fully mature until his 8th year
- something that owners of such individuals have often told me
that they "suspected").
Significance of the Closure Schedule for Injuries to
Back and Neck vs. Limbs
of vertebral "closure" is most significant for two reasons. One:
in no limb are there 32 growth plates! Two: the growth plates
in the limbs are (more or less) oriented perpendicular to the
stress of the load passing through them, while those of the vertebral
chain are oriented parallel to weight placed upon the horse's
back. Bottom line: you can sprain a horse's back (i.e. displace
the vertebral physes - see Figs. 5 and 8) a lot more easily than
you can displace those located in the limbs.
little fact: within the chain of vertebrae, the last to fully
close" are those at the base of the animal's neck (that's why
the long-necked individual may go past 6 years to achieve full
maturity - it's the base of his neck that is still growing). So
you have to be careful - very careful - not to yank the neck around
on your young horse, or get him in any situation where he strains
his neck (i.e., better learn how to get a horse broke to tie before
you ever tie him up, so that there will be no likelihood of him
ever pulling back hard. For more on this, see separate article
in this issue).
Relationship of Skeletal to Sexual Maturity
"maturity" question I always get is this: "so how come if my colt
is not skeletally mature at age 2 he can be used at stud and sire
a foal?" My answer to that is this: sure, sweetie, if that's how
you want to define maturity, then every 14 year old boy is mature.
In other words, the ability to achieve an erection, penetrate
a mare, and ejaculate some semen containing live sperm cells occurs
before skeletal maturity, both in our species and in the horse.
even if you only looked at sperm counts or other standard measures
of sexual maturity that are used for livestock, you would know
that considering a 2 year old a "stallion" is foolish. Male horses
do not achieve the testicular width or weight, quality or quantity
of total ejaculate, or high sperm counts until they're six. Period.
And people used to know this; that's why it's incorrect to refer
to any male horse younger than 4 as a "stallion," whether he's
in service or not.
Peoples' confusion on this question is also why we have such things
as the Stallion Rehabilitation Program at Colorado State University
or the behavior-modification clinic at Cornell - because a two
year old colt is no more able to "take command" on a mental or
psychological level of the whole process of mating - which involves
everything from "properly" being able to ask the mare's permission,
to actually knowing which end of her to jump on, to being able
to do this while some excited and usually frightened humans are
banging him on the nose with a chain - than is a 14 year old boy.
What Does it Mean to "Start" a Young Horse?
Let us now
turn to the second discussion, which is what I mean by "starting"
and the whole history of that. Many people today - at least in
our privileged country - do not realize how hard you can actually
work a mature horse - which is very, very hard. But before you
can do that without significantly damaging the animal, you have
to wait for him to mature, which means - waiting until he is four
to six years old before asking him to carry you on his back.
will happen if you put him to work as a riding horse before that?
Two important things - and probably not what you're thinking of.
What is very unlikely to happen is that you'll damage the growth
plates in his legs. At the worst, there may be some crushing of
the cartilages, but the number of cases of deformed limbs due
to early use is tiny. The cutting-horse futurity people, who are
big into riding horses as young as a year and a half, will tell
you this and they are quite correct. Want to damage legs? There's
a much better way - just overfeed your livestock (you ought to
be able to see a young horse's ribs - not skeletal, but see 'em
- until he's two).
damage to the horse's back from early riding is somewhat easier
to produce than structural damage to his legs. There are some
bloodlines (in Standardbreds, Arabians, and American Saddlebreds)
that are known to inherit weak deep intervertebral ligament sheathing;
these animals are especially prone to the early, sudden onset
of "saddle back'" However, individuals belonging to these bloodlines
are by no means the only ones who may have their back "slip" and
that's because, as mentioned above, the stress of weightbearing
on the back passes parallel to its growth plates as well as parallel
to the intervertebral joints. However, despite the fact that I
have provided a photo of one such case for this posting, I want
to add that the frequency of slipped backs in horses under 6 years
old is also very low.
to worry about? Well...did you ever wish your horse would "round
up" a little better? Collect a little better? Respond to your
leg by raising his back, coiling his loins, and getting his hindquarter
up underneath him a little better? The young horse knows, by feel
and by "instinct", that having a weight on his back puts him in
physical jeopardy. I'm sure that all of you start your youngstock
in the most humane and considerate way that you know how, and
just because of that, I assure you that after a little while,
your horse knows exactly what that saddle is and what that situation
where you go to mount him means. And he loves you, and he is wiser
than you are, so he allows this. But he does not allow it foolishly,
against his deepest nature, which amounts to a command from the
Creator that he must survive; so when your foot goes in that stirrup,
he takes measures to protect himself.
he takes are the same ones you would take in anticipation of a
load coming onto your back: he stiffens or braces the muscles
of his topline, and to help himself do that he may also brace
his legs and hold his breath ("brace" his diaphragm). The earlier
you choose to ride your horse, the more the animal will do this,
and the more often you ride him young, the more you reinforce
the necessity of him responding to you in this way. So please
- don't come crying to me when your six-year-old (that you started
under saddle as a two year old) proves difficult to round up.
Any horse that does not know how to move with his back muscles
in release cannot round up.
if you are one of those who equates "starting" with "riding",
then I guess you better not start your horse until he's four.
That would be the old, traditional, worldwide view: introduce
the horse to equipment (all kinds of equipment and situations)
when he's two, crawl on and off of him at three, saddle him to
begin riding him and teaching him to guide at four, start teaching
him maneuvers or the basics of whatever job he's going to do -
cavalletti or stops or something beyond trailing cattle - at five,
and he's on the payroll at six. The old Spanish way of bitting
reflected this also, because the horse's teeth aren't mature (the
tushes haven't come in, nor all of the permanent cheek teeth either)
until he's six.= This is what I'd do if it were my own horse.
I'm at liberty to do that because I'm not on anybody else's schedule
except my horse's own schedule. I'm not a participant in futurities
or planning to be. Are you? If you are, well, that's your business.
But most horse owners aren't futurity competitors. Please ask
yourself: is there any reason that you have to be riding that
particular horse before he's four?
is a contest for prize money for horses that are two or three
years old. The primary country today where futurities are held
is the United States. If asked to name a famous futurity, most
people here would name "the Snaffle Bit" or "The Lazy E" or a
"World championship" in some breed or other. But the branch of
equine competition in which futurities first began - in the last
half of the 19th century - is racing; and the futurity series
which is now almost the oldest as well as easily the most famous
in the world is the Triple Crown. You see, the Thoroughbred was
invented in the late 17th century by James II of England, who
instigated the world's first performance testing for horses. The
king's object was to induce his subjects to produce a horse that
could carry speed over a distance of ground. To achieve this objective,
he set forth the following rules and invited all the noblemen
and horse breeders to bring any horse they thought could win under
the following conditions:
- The horses
shall run four miles (over undulating terrain, on turf), and
the winner shall be recorded.
- They shall
then rub for half an hour.
- They shall
then run a second heat of four miles, and rub for half an hour.
- They shall
then run a final heat of four miles, and the overall winner
will be the best two of three.
- The horses
shall carry 80 stone apiece (approximately 160 lbs.)
horses that could meet and exceed these requirements is what created
the world's greatest equine athlete - the Thoroughbred.
all the four mile races today? They began to go extinct shortly
after the "futurity" concept was invented, in the late 19th century
- not because racing mature horses four or twelve miles is cruel
(as is sometimes claimed today), but because futurities were invented
as a marketing ploy to give prospective bettors and investors
a peep at what was supposedly coming up from the studs.
horsemen knew that you can't run a two- or three-year-old four
miles; you'd kill him. So they shortened the distance to something
between 7/8ths and 2 miles. Betting interest in these races was
so great - the marketing ploy worked - that they simply outcompeted
the longer "standard" races by becoming the contests that best
fed the tracks. Today, though, this has been forgotten, so that
many perfectly well-intentioned investors simply do not know that
a three year old is not a mature horse and that two year olds
have absolutely no business whatsoever at the racetrack (if all
the two year olds were taken off the track tomorrow, 90% of the
illegal drugs and training techniques would disappear tomorrow,
Of all the
Thoroughbred horses on record that raced as two- or three-year-olds,
and then continued to race until age six or older, only a handful
of them ever posted faster times as youngstock than they did as
six year olds. The horse reaches his physical prime at age six
and (if well managed) maintains that prime until he's about twelve.
In other words - obviously, modern horseracing is not about speed.
Results after each race at the track are not posted in miles per
hour or meters per minute! They don't want the bettor or racing
fan to focus on it. What they care about is astute handicapping
that favors the track ( the unsuccessful $2 bet is what keeps
tracks in business); in short, the focus is not on speed but rather
on contest -- which is merely the appearance of speed.
And the same
may be said for any other division of competition: what organizers,
spectators, commentators and participants care about is contest,
excitement, today's champion against the up-and-coming contender,
whether any horse present is any good compared to universal standards
of quality or not. My point is that YOU - the majority reader
here - are very likely not in that game. My main objective is
to help you get free of imitating your neighbor who may in fact
be trapped in those economics.
one last consideration before I go back to direct discussion of
Ranger's physique. When I say "start" a horse I do not equate
that with riding him. To start a young horse well is one of the
finest tests (and proofs) of superior horsemanship. Anyone who
does not know how to start a horse cannot know how to finish one.
You, the owner, therefore have the following as a minimum list
of enjoyable "things to accomplish" together with your young horse
before he's four years old, when you do start him under saddle:
being touched all over. Comfortable: not put-upon nor merely
tolerating, but really looking forward to it.
includes interior of mouth, muzzle, jowls, ears, sheath/udder,
tail, front and hind feet. Pick 'em up and they should be
how to lead up. No fear; no attempt to flee; no drag in the
feet; knows that it's his job to keep slack in the line all
enough to lead at your shoulder, stop or go when he sees your
body get ready to stop or go; if he spooks, does not jump
toward or onto you, will not enter your space unless he's
specifically invited to do so.
through gate or into stall without charging.
how to tie, may move to the side when spooked but keeps slack
in the line all the time.
how to be ponied.
smooth nonleverage bit in mouth. Lowers head and opens mouth
when asked to take the bit; when unbridled, lowers head and
spits the bit out himself.
work with a drag (tarp, sack half filled with sand, light
tire, or sledge and harness).
drum or sturdy stand with front feet.
longes - comes when called and responds calmly to being driven
forward; relaxed and eager.
driven, leaves without any sign of fleeing; when stopped,
plants hind feet and coils loins; does not depend on back-drag
from your hand to stop him.
with saddle, saddle blanket, and being girthed and accepts
easily, quietly and straight in hand, "one step at a time".
quietly in horse trailer, unloads by stepping backwards from
inside horse trailer without rearing or rushing.
might like to add to this list. Please feel free, just so long
as what you're asking your young horse isn't more than he can
physically do. Getting the horse "100% OK" mentally and emotionally
- those are the big areas in successful early training; most of
the physical and athletic skills can come later, when it is fitting.
people act, when I gave them the above facts and advice about
starting youngstock, like waiting four years was just more than
they could possibly stand. I think they feel this way because
the list of things which they would like to include as necessary
before attempting to ride is very short. Their whole focus is
on riding as why they bought the animal, and they think they have
a right to this. Well, the horse - good friend to mankind that
he is - will soon show them what he thinks they have a right to.
The Bottom Line for Ranger
to say about Ranger? By the time he's fully mature, he'll have
a more muscular neck, which he will want (if he's allowed in the
training process) to arch more at the base but carry lower at
the poll. His back will be a little longer than it now is, the
withers will definitely be higher, and the loins a little broader.
His pelvis will be longer and the musculature covering it will
be much fuller. He has (typical of Walking Horses) already a tremendous
shoulder and a wonderful long arm - he'll have a very long, flowing
forward reach. He has good crisp hocks and is not more crooked
in the hind limb than I think proper for his breed - he's only
slightly more angulated/long in the hind limb than I would ideally
like. He's got adequate "bone" and good-sized, well-shaped hoofs.
back is held a little stiffly and I'm sure the owner knows why
by now. Many folks who own gaited breeds complain that they (TWH,
Pasos, ASB, Rocky Mtn., etc.) have a "tendency" to hard-pace rather
than four-beat gait, and this also comes from the habitual stiffening
of the back. Gaiting (all forms of it) has the same footfall order
and basic mechanism as the ordinary walk. But no horse can walk
in good rhythm with good "reach" and good "nod" unless his back
is free to oscillate both up and down and (especially) from side
to side in time with the motions of his legs. Take away the emotional
worry and mental concern...teach the animal to release the muscles
of his topline and those of the crest of his neck...and all your
concerns with whether he has a good "nod" or why he is maybe pacing
are going to fade right away.
writing in, and please give ol' Ranger a little scratchin' in
his favorite spot for me.