You can determine the appropriate carrying capacity of your horse by following the 20-percent rule, and considering fitness, conformation, activity level and equipment.
Understanding your horse’s weight carrying capacity can ensure their welfare and continued partnership for years to come.
Common activities where horses carry weight
In the United States, horse owners commonly use horses for recreational and competitive riding. In a recent federal census, the leading use of U.S. horses was for recreation (47 percent), which ranges from trail riding to arena work. Farm and ranch work followed at 25 percent, which can include sorting cattle, carrying equipment in packs and pulling carts or lumber.
When asking our equine partners to participate in these activities, we also need to consider their welfare. Owners must be aware of how much work is appropriate for their horse. In order to help determine this, researchers have studied the ideal weight carrying capacity of horses.
How much weight can your horse carry?
In 2008 at an Ohio University, researchers evaluated the impact of rider and tack weight. They monitored horses for heart rate, breathing rate, rectal temperature and loin muscle condition when carrying loads of 15, 20, 25 and 35 percent of their bodyweight.
The researchers found that an average adult light riding horse could comfortably carry about 20 percent of their ideal bodyweight. This result agrees with the value recommended by the Certified Horsemanship Association and the U.S. Cavalry Manuals of Horse Management published in 1920.
What affects how much your horse can carry?
Researchers in Ohio found that loin width and cannon bone circumference relates to weight carrying capacity. Horses with wider loins and greater cannon bone circumferences had less muscle soreness as their weight load increased. This finding indicates the 20-percent rule is a good starting point.
Another study looked at Arabian endurance horses carrying between 20 and 30 percent of their bodyweight. Among these horses, lameness was more common in horses with smaller cannon bones (i.e. smaller cannon bone circumference).
Compared to the average Arabian horse, Icelandic horses are more compact and tend to have thicker cannon bones. In addition, Icelandic horses are regularly seen carrying adult riders despite their small stature. To evaluate effects of this type of work, researchers studied Icelandic horses carrying between 20 and 35 percent of their bodyweight. They found that the horses had no muscle soreness after one to two days of work and most were able to work aerobically (with oxygen) until they reached a weight load of 23 percent.
Aerobic muscle function allows the horse to use reserve energy and oxygen to contract muscles without fatigue. When oxygen is lacking, the horse must use alternative pathways, which can result in the buildup of lactic acid and muscle soreness.
These researchers also found that stride length decreased as weight load increased. However, the decrease in stride length did not affect stride symmetry.
When describing a horse that can easily carry weight above the 20-percent rule, think of a well-balanced horse that has a short, well-muscled back and thick cannon bones. This horse will also have a lower center of gravity compared to a horse with long legs and a long, weak back. Overall, riders should be aware of structural weaknesses in their mounts and make sure that their fitness plans address these weaknesses.
Horse and rider fitness and balance may also impact weight carrying capacity. Fitness and balance determines how well the horse and rider can use their body. Unfit or unbalanced horses won’t have the strength to appropriately lift their back and support the weight of the rider while maintaining their own balance. Research shows that horses with a more developed topline better tolerate an increased workload, which leads to reduced muscle soreness.
An unfit rider can also throw off a horse’s balance as they try to maintain correct riding position and fight the effects of muscle fatigue.
Activities that occur over rough terrain, for longer durations and at increased speeds will require more effort from the horse. Only attempt these activities if the horses and riders are fit enough to do so.
Always make sure your equipment meets the needs of the activity. Your saddle should be fit to your horse’s back to best distribute the weight of the rider without pinching or causing muscle soreness.
Also make sure to provide your horse routine hoof care. Hooves should be trimmed to ensure a balanced, flat surface for weight bearing. For horses that wear down hooves faster than they can re-grow, or those with thin soles, consider adding shoes or protective boots based on advice from a reputable equine professional such as your farrier or veterinarian.
Reviewed in 2019