Conformation is nothing more than the lines, angles, and ratios that make up the physical body of a horse. Each breed has a different ratio, and each job type has different angles, and this is what makes a horse either a good example of the breed, or a poor one.
As horse lovers, it is easy to look at pictures of certain breeds and identify them without question. Arabians have lean bodies and dishy heads. Percherons have large bones and massive muscles. But, when you start to look at the angles of a good horse, you quickly realize that both should have a forty-five degree slope to the shoulder, and a ninety degree angle between the shoulder and the elbow. This is considered the standard for good conformation (and is only one example), so what is it that makes the Percheron different from the Arabian horse?
This is the dilemma that has caused breeds to shift and morph over time, moving from one accepted appearance to a completely different one. Look at pictures from early twentieth century draft horse, and compare them to the horses in the show ring today, and those changes become apparent. Words such as heft, bone, substance, and muscling are tossed around, but they are not the only reasons why horses tend to change over time. The ratio of the horse is also important.
We may instinctively understand that a Percheron is not simply an oversized Arabian, but explaining why is much harder. Both breeds typically have large hooves compared to their body size; but, the ratio of the cannon bone to hoof is larger in the Percheron than the Arabian. The comparison of head size to width of chest is also greater. These ratios are what our eyes see - and our brain instinctually comprehends - to allow us to identify a horse's breed from nothing
Conformation 101
"While the
angles of the joints effect the attachment of the muscles – and in many cases predict the soundness of the animal - the ratio of body parts makes up the phenotype of the breed."
8 The Hitching Post/February, 2014