191--point of hip to point of buttock
Lemme have a go at this. Pastern is very good length in comparison to the cannon bone, and the cannon bone is proportionate to the forearm. The shoulder length is correct in being more than 1/3 of the length of the body line. The humerus is good in being more than 50% of the length of the shoulder. The shoulder is a bit on the steep side, correct? And the shoulder angle at 96 degrees is somewhat closed, off of the ideal of 100 degrees. I think the long scapula makes up for this, correct?
The forearm is only 123 compared to the 131 humerus, but I'm not sure how I was supposed to measure the forearm. I used the point of the elbow to the knee. The cannon is okay in proportion to the forearm. The pastern is great in relation to the length of the cannon.
Looking at the rear end, the line from the point of the hip to the point of the buttock is a bit too short in comparison to the length of the body line at 31.9%. Not so much, however, that it impedes upon the amount of thrust the horse has from behind. Femur length at 187 is close to the measurement of the point of hip to buttock (191), so they're equal there. The pelvis length is a bit short and doesn't quite favor the idea of the equilateral triangle, but at 181 it's close enough. Arthur seems to have a powerful rear end.
A horse's back is built like a suspension bridge. Like that suspension bridge when we add weight to the horse's back it "sags"... and like the bridge in order for it not to "break" we need to make sure it has strong anchor points in order to have a strong back.
The first place to look is where the wither blends into the spine. You want to see a clear wither, not too high, not too low, you want it to blend smoothly into the back. Having a high wither often results in getting a "shelf" behind it -which will put some strain on the vertabrae, but also make finding a good saddle fit difficult - if your saddle doesn't fit your horse is going to be far less likely to work properly... and that's when injuries happen.
We're going to draw a line from the top of the wither to the horse's LS joint (just ahead of the croup). This is our back length line.
We're also going to make a short, verticle line at the last rib of the ribcage - and make sure that line intersects with the body line. Then one more line from the top of wither to that small verticle line you just made. This is the ribcage length line.
The length of these lines will be our back length, and our ribcage length.
The length of a horse's back is of less importance to us than the strength of that back - it's very possible to have a long back which is also strong, just as a short back can also be weak.
Now, while length of back isn't "primary" concern for us, we don't want too long of a back, or it will through the balance of the horse out too. Generally, we want a back no more than 50% of the body length in order to maintain that square horse.
The ribcage length is going to help determine the length, therefore strength, of loin. We want to see the ribcage length being 98% or more of the back length.
To go with Loin length... we're going to look at loin girth depth. Loin girth is the area from the loin to the bottom of the horse's flank - the deeper (longer) that space is, the stronger the loin is, because there's more horse there to give it support.
Another thing we're going to look at is the position of the LS joint. This joint is the rear anchor to the horse's back, and we find it by locating the soft, squishy spot on the horse's spine (right on top) just ahead of the point of croup. In a perfect world the LS would be placed ahead of the hips... but a good placement would be even with the hips... and it get weaker the further back we go. The placement of the LS is not only a factor in the strength of the back, but also in the ability the horse has to round out and collect. A horse with an LS placement too far back will never reach levels of "sit" that a horse with one further ahead of the hips will be.
We're going to then put the whole back together as a whole picture of the horse's back. What can you tell me about your horse's back?
Equiniphile - yep... pretty good.
The length of the scapula can offset a steep angle... a little, the humorus being more than half that length is going to help more so. If your boy is gaited, then his shoulder is likely a reflection of the type of movement desired within the breed (I thought you mentioned he was Peruvian or Paso Fino in another thread?)
While "good conformation" is good conformation, there are variances within breeds which desire different movement.
191--ilium length (point of hip to point of buttock)
31.9%--hip to buttock over body line
187--femur length (buttock to stifle)
Yes, he's a Paso Fino. They're supposed to have short backs, I've heard
I just realized I somehow missed the rest of the hind leg.
So, ideally, when we stand a horse up so that his cannons are verticle to the ground, his hock, tendons, fetlock and heel are going to line up to that side of the box. Naturally, horses aren't always so co-operative with photographers and this means sometimes we can't get that perfect stance captured "on film" but with some practice you can learn to visualize what the leg would look like - as long as it's not out by too much.
A leg which extends past the box with the cannons on the verticle is "camped out" - or over angulated. This is quite common amongst gaited breeds, or trotters, but can be seen in other horses as well. While this doesn't generally impede the horse, and often will actually allow for more reach through under the horse while it's moving, it can also make it harder for the horse to lift it's back and work truly round.
A leg which falls short of the line while the cannons are verticle is said to be "post legged" - or lacking of angulation. Post legged-ness is one of those faults which is going to make for a rough ride. The angulation of the hind limb is there to help absorb shock, as well as propell the horse forward - so the lack of it will reduce the shock absorption and make the hind legs shorter strided. It will also impede the horse's ability to round out and move correctly.
(as a note, many horses who are growing will appear post legged while they are still bum high... and often horses who are built downhill will be post legged - but not necessarily)
Now let's add a neck length line... top of wither to the poll. Generally speaking we want a horse to break into thirds... so 1/3 of the body in neck, 1/3 in back and 1/3 in hindquarter... but many people prefer a slightly longer neck on their horse.
Whether a horse has a short or long neck doesn't matter so much as the shape of that neck and how it ties into the chest and wither. How "thick" the neck is will also help or hinder the horse's ability to balance and round out properly, but not nearly as much so as the natural shape, or structure of the neck.
The "ideal" is a slightly arched neck shape... not so much so that the horse has a "swan neck" but not arched on the underside either. We want it to tie in about the "middle" of the chest, too low and you lose depth of chest and more weight gets shifted onto the forehand, too high and you'll lose the ability for the horse to reach long and low easily and relaxed as the tendency will be for the horse to try and seek it's balance in an inverted frame. A straight neck is better than "upside down" arche (ewe neck), but not as good as an arched neck.
I would say you can safely go to about 50% of the body length as neck without drastically losing balance to the body and as little as 30% of the body length without getting ridiculously short. Horses with a longer neck are generally better able to balance themselves, especially for jumping where they can use that extra length as a counter balance... horses with a shorter neck will often find it more difficult to get off the forehand.