Methods to Calculate How Much Weight A Horse Can Carry
2008-02-09 13:00:00 - source: Susan Garlinghouse; Dr. Deb Bennett - by iceryder
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[ ADVICE ] There are a few methods to use to calculate how much weight a horse can carry.
One is simplistic: A rough guide to how much weight a horse can carry is to take the horse's weight (in lbs) and divide it by six. This equals the total weight the horse can carry, including tack.
Or the 20% Rule: 1000 lb horse can carry 200 pounds.
Another formula is based on measuring the bone:
When people speak of a horse's "bone", they are referring to a measurement taken at the circumference of the foreleg, just below the knee. Horses have very slim legs, and a great deal of weight and mass to carry, so the quality of their support structures is very important.
The foreleg circumference measurement can help determine the horse's ability to carry weight. A light-boned or refined horse will be limited in weight carrying capacity. A regular-sized horse with "good bone" can measure 21.75cm (8 1/2 inches) or more.
The maximum weight a horse can carry safely varies according to the breed of the horse and its usage. There is no absolute rule about how much weight a horse can carry, but generally speaking the lighter-framed the horse the less he can carry.
Native ponies are very strong and even some of the individuals in the small breeds are capable of carrying adults without difficulty. It is much easier for a horse to carry a fit, well-balanced rider, than an unfit, overweight unbalanced rider, even if they both weigh the same.
Quality of bone is something else, and more variable. Some horses that have had poor nutrition, over-fed, or over-stressed at a young age may have poor quality bone; in this case, even a good external measurement may be inaccurate in regard to weight carrying ability. Some of the smaller breeds are known for the quality of their bones: Arabians, for instance.
So "bone" and "quality" are not such simple concepts or easy to measure!
A study done of the Tevis horses and rider weight is available on Susan Garlinghouse's website. The study concluded that condition score is more important than rider weight compared to the weight of the horse. It's also important as to how much the horse weighs and how much the rider weighs as the combined weight is what the horse carries. The more weight the horse carries, the more stress and strain, simple physics. The more weight the horse carries, the more potential lameness. Long, slow, steady conditioning is more important for the heavy-weight rider, as well as cover on the horse's back and ribs. See Susan's website for more details on the study
Dr. Deb has some information about weight carrying ability of horses on her site
She indicates that there is no strict weight ratio, and that "as height goes up in horses, soundness, weight carrying ability, and degree of coordination and agility all tend to go down..." and that the length of the back also plays into the variables of the amount of weight a horse can carry: "the shorter the back, the more weight the animal will be able to pack and the longer time it will be able to stand being ridden before fatigue sets in."
Dr. Deb says that the length of back is not the most important factor, but that the width of the loins is more important. "The broader the loins, the greater the weight-carrying ability no matter WHAT the overall size or height of the horse may be."
The loin (coupling) should be well-muscled and strong as opposed to being long, weak and poorly muscled. The loin is the pivot point of the horse's back and is the area between the last rib and the croup. Short, muscular loins are needed to carry power from the hind legs forward.
Another consideration is the "flexibility" of the back. Flexibility can be mistaken as a positive attribute, but it may be indicative of a weak back!
There are a couple of different ways to measure the loin. One is to measure the heart girth and then take the loin/groin measurement. The closer these figures are, the better, assuming that the heart girth itself is substantial.
Or you can measure the loin area right on top. The width of the loin ends where the ribs start to curve downwards. Well-sprung ribs should help contribute to a wider loin area.
Before buying a riding horse, you'll want to check the loin width, and also check to see if the loin muscles are strong. This is done by feel. If the loin has been stretched, the muscles will feel stringy with no substance. If you haven't guessed, this is not good, especially for a riding horse, and particularly for a large rider. Unfortunately, horses ridden with stiff backs tend to have weak loins. Riding in the "lounge chair" position contributes to this weakening.
Note : If opinions are expressed in this text, they don't necessarily reflect those of horsetype.com.
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