Scooter, left, at 14-hands high and 750 pounds, probably can't carry as much as skywalker, right, at 16.1 hands and 1,150 pounds. But the difference may less than you think. Read on for details.

Recently, trainer Travis Young and I took a rapid ride around our east range, climbing from the valley floor some 400 feet, descending a coulee on the far side of the ridge to check a spring needed to water the cattle, then back up the ridge and down to the home place again. We traveled three or four miles in about 40 minutes, our horses covering the rough terrain alternating between a brisk flat walk and, for short stretches, a running walk. We take such rides frequently as part of our training program, Travis riding a green colt, I accompanying him for safety on a more seasoned horse.

Both mounts on this particular day were registered Tennessee Walking Horses, but beyond that, they had very little in common. My horse, Skywalker, is 5 years old, a bit over 16 hands high, still growing, and weighs perhaps 1,150 pounds. Travis was riding Scooter, a diminutive bay recently nabbed from our sales list by my petite wife, Emily. Standing just 14 hands at age 3, Scooter will grow a little more but will probably never be taller than 14.2 hands. He now weighs approximately 750 pounds.

Adding 50 pounds to our own weights for Western saddles, tack, and clothing, Scooter was carrying 215 pounds, just under 30 percent of his weight. Skywalker carried 265 pounds, 23 percent of his weight. The United States Cavalry limited the total loads of saddle mounts to 25 percent of body weight, while some modern riding stables limit the load to 20 percent.

Skywalker was carrying a load close to these parameters. Since he’s in good condition, already a seasoned mountain horse, it’s not surprising that he handled me with relative ease on a short, quick ride over rough terrain. Scooter, however, was overloaded by these standards and should’ve had difficulty.

Quite the opposite was true. Scooter set the pace. He scampered like a jackrabbit around sagebrush clumps, descended a steep coulee with cat-like surefootedness, and projected a “let’s get it done” attitude throughout.

It’s questionable to attribute human characteristics to horses, but Scooter seemed to be enjoying himself immensely. According to the percentage guidelines commonly used by many in the equine world, Scooter was overloaded, yet he didn’t seem hampered at all by the weight he was carrying. Why?

Percentage Problems
The truth is, estimates that measure weight-carrying ability by a percentage of the horse’s weight are incomplete at best, and downright misleading at worst. First, they assume you know the horse’s weight, which is open to question.

Beyond that, imagine a rock-hard, healthy horse weighing 1,000 pounds, just thin enough to show a suggestion of rib, in superb muscular and cardiovascular condition from frequent, challenging riding. Now we turn that horse into a lush timothy pasture for many months, don’t ride him, and find he’s ballooned up to 1,150 pounds. Percentage guidelines would claim he could now carry more than before, but that’s ridiculous. He can now carry less, because he’s burdened with the weight of useless fat in addition to the weight of the rider, and his physical conditioning has plummeted.

Interestingly, superfluous muscle can have a similar effect. An extremely heavily muscled horse can probably safely carry a smaller percentage of his weight, not a larger percentage, than a more moderately muscled horse. Muscle is very heavy, and unless it’s of a type that directly aids the horse in carrying weight, it’s burdensome baggage. This is why we see few NFL linebackers running marathons or climbing mountains with packs on their backs.

The problem with weight-carrying estimates based on a percentage of the horse’s own weight is the many things not considered. Key are speed traveled and total distance to be covered, the type of terrain being traversed, conformation, physical conditioning, distribution of weight on the horse’s back, and the ability of the rider. Let’s look at each of these.

During the days when the U.S. military moved much of its supplies on the backs of mules, the army became expert on the relationship of distance, speed, and terrain to be covered as they related to allowable loads. Writing in 1914, Charles Johnson Post reported in Horse Packing that the standard load for a pack mule weighing between 950 and 1,020 pounds was 250 pounds, to be carried over average terrain for 25 miles each day on a continuous basis, no days of rest needed.

The army then used a sliding scale considering the weight carried, the speed, the distance covered per day, and the days of continuous travel. Increasing any one of these factors required compensation by reducing one or more of the other factors. For instance, the pack mules could carry that same 250 pounds at six miles per hour and cover 50 miles in a day, but only for five days of continuous travel. The loads listed run all the way to 400 pounds!

The point for the trail rider is simply that you can’t compare a slow, easy ride over a smooth, groomed trail with a long one at brisk speed over rough terrain. On the former, a good horse in good condition may be able to carry a load far in excess of the percentage guidelines used by stables, and the opposite may be true for the faster, longer, rougher ride — particularly if a similar ride is to be taken the next day. Keep in mind, too, that commercial outfitters must worry about liability and are likely to err on the conservative side.

Size & Conformation
But all horses aren’t equal in the load-carrying department. As a general rule, smaller horses can carry a higher percentage of their own weight than larger horses. The 1,300-pound warmblood should be able to carry a heavier load than a 500-pound Shetland pony, but the percentage of his own weight that he can carry is considerably less.

Here’s why: Four-legged animals begin to lose efficiency as their size increases, because their own weight becomes more of a burden to them. The U.S. Army, according to General William H. Carter in The U.S. Cavalry Horse (written in 1895), settled on 950 to 1,100 pounds as the ideal weight for saddle horses, with heights from 15 hands to 15.3. Larger horses didn’t perform as well. True, the cavalrymen themselves were light, but total loads with the gear they carried ran close to 250 pounds, and the horses had to be capable of strenuous performance.

Most packers today limit their loads to around 150 pounds, because a pack horse must carry dead weight.

Of course, the military had to be concerned with such things as speed and jumping ability, not just weight-carrying capability. The modern trail rider, on the other hand, who’s probably heavier than the 19th-century cavalryman, is unlikely to be charging an enemy or pursuing anyone at a gallop. So trail riders should elevate the importance of conformation “designed” to carry weight. Because of conformational differences, it’s possible that a 14.2-hand Peruvian Paso might be able to carry a 225-pound man more easily than can a 16.2-hand Thoroughbred. How can this be?

For starters, what has each of these breeds, for several centuries, been selectively bred to do? The Paso was bred to cover many miles over rough terrain in smooth gaits at moderate speeds. The Thoroughbred was bred to carry a light rider at very high speeds. No single build is optimum for both. For carrying weight, a short back is mandatory; for winning the Kentucky Derby, a longer back is required.

But equine-physiologist Deb Bennett, PhD, tells us that along with shortness of back, there’s another conformational feature absolutely necessary for good weight-carrying ability, and that’s broadness (width) of the loin. The loin is the mass of muscle lying behind the rib cage and in front of the hips. It runs from each side of the backbone down toward the belly. This is the primary muscle that gives strength to the back against a force pushing downward.

Dr. Bennett points out that most Welsh ponies, Peruvian Pasos, older style Morgans, Saddlebreds, and Tennessee Walking Horses — horses she calls of the “saddle type” rather than “racing type” — have “loins that are short, broad, smooth, and deep (measured circumferentially or vertically from loin to groin).”

She describes the process online in The Inner Horseman: “Essentially, you feel of your horse’s back, and find the place behind the ribs but ahead of the hips where he has a kind of ‘waist.’ Then you go up on top and run your hand down from the midline toward his belly, feeling for the place where your hand starts to fall off most steeply. That point is the width of his loins on that side, i.e., the width of the flesh-covered lumbar transverse processes.”

This, then, is the reason many smaller horses can carry just as much weight as those much larger: Their loin measurement is equal to or greater than their big cousins with racing blood. It’s also the reason why the heavier trail rider must look beyond the animal’s size and weight when choosing his or her horse.

How to Ease the Burden
You’ve likely already chosen your trail horse, so the best you can do is evaluate him along with these conformation guidelines to get an idea of his limitations, then do what you can to ease the burden. The first and most obvious step is to get him in condition. “A lean horse for a long pull,” the old-timers said. A fit horse will carry weight better than a fat horse, so a graduated training program — increasing distance, speed, and weight on his back — is mandatory preparation for major rides.

Then, look to your own fitness level. Most of us can stand to lose a few pounds, and with trimmer physiques, we tend to ride better, which also makes it easier for the horse. Professional packers today usually limit the loads on their pack horses to around 150 pounds, far less than the weight carried by the saddle horses their clients ride.

The reason is simple: A pack is dead weight, while a rider moves with the horse. Good riders have a fluid connection with the horse’s movements. We mustn’t ride like packs on a horse’s back, unyielding, out of synch with his motion. The better we ride, the easier it is for the horse.

Thus, all weight isn’t equal, and this applies to its distribution on the horse, as well. Keep weight as much above your horse’s center of gravity as possible. The center of gravity of most horses is fairly far forward, just behind the foreleg and about one-third of the way up his body. A weight that a horse could handle relatively well carried up close to his withers could cause terrible damage if placed back behind the saddle over his kidneys. Because of this, the popularity of many single-horse packing systems is becoming a problem. 

A human backpacker in good physical condition often carries a pack weighing 50 pounds or so. Can you put that much weight on your saddle horse, along with your own weight and that of the saddle, without overloading him? The answer depends on all the factors we’ve discussed thus far, plus where you position the extra weight on your horse’s back.

Too many single-horse packing systems, marketed so that you can carry all necessary camping gear on your saddle horse, are simply too large. The oversized saddlebags, sometimes with a pack over the top, tempt you to fill them with unnecessary items. The result is excessive weight in the worst possible place, just behind the saddle.

Yes, single-horse overnighting can be done, but you must pay even more attention to weight than the backpacker does. You probably need a few horse-related items — such as a curry, hobbles, and picket rope — that a backpacker doesn’t need, which adds to the weight. Forget taking luxuries. Put the heaviest items in horn packs, in front of you, and only soft, light items (such as a down sleeping bag and light clothing) behind the saddle.

Should you be traveling into an area where grazing is prohibited, note that packing feed will put the weight over the top of the acceptable limit.

To be light on the land, we should take as few animals as possible into the backcountry, but we must also spare our horses’ backs. For full-fledged horse-camping trips, consider learning the skills necessary to pack your gear on a separate horse. (We’ll give you a packing primer in the next issue of The Trail Rider.)

You and two friends can share one pack horse, each of you contributing 50 pounds to the load. This will spare your saddle horses. You’ll gain in safety, as well. Your lightly loaded saddle horse will be better able to handle rough terrain, and you’ll be able to mount and dismount with greater ease. Both you and your horse will enjoy happier trails.

Dan Aadland ranches and writes in south-central Montana, where he and his wife, Emily, raise mountain-bred Tennessee Walking Horses. His five books include The Complete Trail Horse: Selecting, Training, and Enjoying Your Horse in the Backcountry (The Lyons Press). For information on Aadland’s horses, clinics, training, and books, visit http://my.montana.net/draa.