Horse breeds · from TrotleyRocky Mountain Horse weight and height, with silver coat and PSSM1 notes
Rocky Mountain Horses stand 14.2 to 15.2 hands and weigh 850 to 1,000 pounds, and two UC Davis genetic tests concern the breed: one for the eyes that goes with the silver coat, one for a muscle disease.
Short answer
Rocky Mountain Horses stand 14.2 to 15.2 hands and weigh 850 to 1,000 pounds, about 386 to 454 kg.
The Livestock Conservancy gives 14.2 to 15.2 hands and 850 to 1,000 lb (386 to 454 kg). The breed standard, as quoted by Oklahoma State University and the International Museum of the Horse, allows 14.2 to 16 hands and sets no weight.
The Livestock Conservancy, Oklahoma State University and International Museum of the Horse
| Source | Height | Weight |
|---|---|---|
| The Livestock Conservancy | 14.2 to 15.2 hands | 850 to 1,000 lb (386 to 454 kg) |
| Breed standard quoted by Oklahoma State University | 14.2 to 16 hands | Not given |
| University of Minnesota, 214 saddle-type horses (gaited horses included) | Average 60 inches (15 hands) | Average 1,133 lb |
The Minnesota group mixes several gaited breeds and is shown for comparison only.
A gaited breed with a written standard
Oklahoma State describes a medium-sized, gentle horse with a natural four-beat ambling gait, a solid body color and no white above the knee or hock. Each horse is examined and approved before it can be bred, and the Rocky Mountain Horse Association has kept the registry since 1986.
The Livestock Conservancy calls the breed calm and friendly, used for trail riding, endurance and rail classes.
Daily hay for a 925 pound Rocky Mountain Horse
The midpoint of 850 to 1,000 lb is 925 lb, so the arithmetic below uses that.
Merck says adult horses usually eat 2 to 2.5% of body weight in dry matter at most, with at least 1.5 to 2% coming from forage. Oklahoma State calls the breed an easy keeper, so the lower lines often suit a horse at rest. These figures are our arithmetic, counting hay as 90% dry matter.
- 1.5% of body weight: 14 lb (6 kg) of dry matter, about 15 lb (7 kg) of hay
- 2% of body weight: 18 lb (8 kg) of dry matter, about 21 lb (9 kg) of hay
- 2.5% of body weight: 23 lb (10 kg) of dry matter, about 26 lb (12 kg) of hay
A weight tape example for a Rocky Mountain Horse
The horse weight calculator uses the adult equation in the Merck Veterinary Manual: heart girth squared times body length, in inches, divided by 330. A heart girth of 70 inches and a body length of 62 inches gives 70 x 70 = 4,900, times 62 = 303,800, divided by 330 = about 921 lb (418 kg). Those measurements are our illustration, not a real horse.
Merck says weight tapes work on horses, tend to read low and are best for following change over time.
Silver coat and the eye test
UC Davis uses a Rocky Mountain Horse to show the silver dilution, which lightens a black horse’s coat toward chocolate and its mane and tail toward flaxen or silver gray, and it lists the breed among those that carry the variant. The same variant is linked to multiple congenital ocular anomalies: ocular cysts, an enlarged cornea and abnormally formed iris or retina.
One copy usually means a milder eye form and two copies a more severe one. A chestnut horse with the variant is not silver but can still develop the eye problems. A hair sample with roots goes to the laboratory, and your vet can examine the eyes of a horse you plan to buy or breed.
PSSM1 and a horse that tires or tightens
UC Davis lists the Rocky Mountain Horse among the breeds in which type 1 polysaccharide storage myopathy occurs. Affected horses store abnormal sugars in muscle, and the signs include muscle pain, weakness, skin twitching, sweating and reluctance to move.
A horse that stiffens or refuses to go forward after light work needs your vet, who can decide whether the DNA test fits.
Easy keepers and pasture
Merck explains that horses with obesity and insulin resistance are predisposed to pasture-associated laminitis, and UC Davis names lush, sugar-rich pasture as a trigger. A breed called an easy keeper is the kind of horse that gains on spring grass. Limit access when weight climbs and call your vet at the first sign of foot pain.
Body condition
Merck advises keeping a horse at 4 to 6 on the 9 point Henneke scale, with 7 or more counted as overweight. The University of Minnesota found saddle-type horses averaged a score of 6.0. Score by feel over the ribs, loin and crest, and write the score down next to each weight.
Frequently asked questions
How much does a Rocky Mountain Horse weigh?
The Livestock Conservancy gives 850 to 1,000 pounds (386 to 454 kg) for horses of 14.2 to 15.2 hands.
How tall is a Rocky Mountain Horse?
The Livestock Conservancy lists 14.2 to 15.2 hands, which is 58 to 62 inches at the withers. The breed standard allows up to 16 hands.
Can a Rocky Mountain Horse carry a 190 pound rider?
The University of Minnesota reports that an average adult light riding horse can comfortably carry about 20% of its ideal bodyweight, rider and tack included. For 925 pounds that is about 185 pounds, and 23% is about 213 pounds. A 190 pound rider with 25 pounds of tack is 215 pounds, or about 23% of 925 pounds. Fitness, conformation and the kind of riding change the answer, so ask your vet if you are close to the line.
Why is my chocolate horse’s eye cloudy or cystic?
UC Davis links the silver dilution to inherited eye anomalies such as ocular cysts and an enlarged cornea. Any change to a horse’s eye is a reason to call your vet, and a DNA test can show whether the silver variant is present.
Sources
- The Livestock Conservancy, Rocky Mountain Horse
- Oklahoma State University, Breeds of Livestock: Rocky Mountain Horses
- International Museum of the Horse, Rocky Mountain Horse (archived copy)
- UC Davis Veterinary Genetics Laboratory, Silver (archived copy)
- UC Davis Veterinary Genetics Laboratory, Multiple congenital ocular anomalies (archived copy)
- UC Davis Veterinary Genetics Laboratory, Polysaccharide storage myopathy type 1 (archived copy)
- University of Minnesota Extension, Guidelines for weight-carrying capacity of horses
- University of Minnesota Extension, Estimating actual and ideal bodyweight of adult horses
- Merck Veterinary Manual, Nutritional Requirements of Horses and Other Equids
- Merck Veterinary Manual, Laminitis in Horses
- UC Davis Center for Equine Health, Laminitis (archived copy)
Checked on October 2, 2026.
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See TrotleyMore in Horse breeds
- Tennessee Walking HorseA Tennessee Walking Horse weighs 900 to 1,200 pounds and stands 14.3 to 17 hands.
- Missouri Fox TrotterA Missouri Fox Trotter weighs 900 to 1,200 pounds and stands 14 to 16 hands.
- MorganA Morgan weighs 900 to 1,100 pounds and stands 14.2 to 15.2 hands.
- American SaddlebredAn American Saddlebred weighs 1,000 to 1,200 pounds and stands about 15 to 16.3 hands.
- Akhal-TekeAkhal-Tekes average 15.2 hands and weigh 900 to 1,000 pounds, about 408 to 454 kg.
- American Miniature HorseMiniature Horses stand no more than 34 inches, and adults average about 257 pounds.
- Horse weight calculatorFree tool: Estimate a horse’s weight from heart girth and body length with the formulas in the Merck Veterinary Manual, for adults, yearlings and weanlings.
