The Standardbred is an American breed developed for the sport of harness racing. But just like their Thoroughbred ancestors, these horses can go on to successful second careers as riding horses after they leave the racetrack.

Standardbreds are classified as trotters or pacers depending on the gait they use for races. Bred initially from horses that could trot one mile in a standard time, the American Standardbred is now the fastest trotting breed in the world.

While high-stress racing careers can lead to health problems even after Standardbreds arrive at their new homes, careful management can help these horses thrive. Many Standardbred owners enjoy these ex-racehorses as friendly and willing pleasure mounts.

This article will review the origin, history, characteristics, common health problems, and nutritional needs of the Standardbred breed. Keep reading to learn more about caring for and feeding Standardbred horses.

Standardbred Horse History

The Standardbred’s origin story is closely linked to the history of harness racing in America. As the sport grew in popularity, new breed standards emerged, creating the modern trotters and pacers that dominate Standardbred racetracks today.


Settlers first raced trotting horses under saddle in the fields and village streets of Colonial America. Many of these horses were Narragansett Pacers, the first horse breed developed in North America.

By the mid-19th century, trotting races moved to official racetracks and featured harnessed horses pulling drivers in carts. Bloodlines from Thoroughbreds imported to sire flat racing horses at the time also heavily influenced the new breed of harness horses.

Messenger, a gray Thoroughbred stallion imported in 1788, played a central role in developing the modern trotting breed. His great-grandson Hambletonian 10, foaled in 1849, is considered the foundation sire of the American Standardbred. [1]

Other influential breeds that contributed to the development of the Standardbred include the Canadian Pacer, Norfolk Trotter, Hackney, and Morgan.

The name Standardbred arose from the standard trotting speeds required of breeding stock. At the time of the breed’s founding, horses had to trot one mile in under 2 minutes and 30 seconds to be included in the breed registry.

Historic Use

Colonial Americans used the ancestors of Standardbreds as working horses for transportation and farm work. Eventually, interest in recreational trotting races pushed breeding practices towards producing faster mounts explicitly bred for racing.

While harness racing events were held at county fairs as early as 1825, the first official American harness racing tracks opened in the mid-1800s. By the early 1900s, it was one of the fastest-growing sports in America. [2]

Harness horses pull a driver in a two-wheeled cart during races. These races are conducted in two different gaits, the trot and the pace. Trotters move their legs forward in diagonal pairs, while pacers move lateral pars simultaneously.

Today, breeders develop slightly different bloodlines of Standardbreds to specialize as trotters or pacers. But both trotters and pacers can trace their lineage back to Hambletonian 10.

Breed Registry

The National Association of Trotting Horse Breeders established the standards that distinguished the Standardbred horse as a unique breed in 1879 and launched the trotting horse registry. [1]

After harness racing surged in popularity in North America, the U.S. Trotting Association emerged in 1939 to organize the industry as the sport’s sole regulatory body. The USTA continues to maintain the breed registry for Standardbred horses today. [2]

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Breed Characteristics

While Standardbreds share bloodlines with Thoroughbreds, the breed has developed unique characteristics that allow these horses to excel in their sport and beyond. These differences are most apparent in their conformation and temperament.

Standardbred Horse Breed Profile | Mad Barn USA


The average Standardbred is shorter but slightly heavier than most Thoroughbreds, with a height range of 14.2 to 16.3 hands. These horses have longer bodies with narrower chests, sloping shoulders, muscled hindquarters, and medium to long necks.

The ideal Standardbred has a refined head, a straight profile, and large nostrils. More muscular, shorter legs and higher haunches produce long, balanced trotting strides at high speeds.


Standardbreds can be any colour, but bay and brown are the most common. Other colours found in Standardbreds include black, chestnut, grey, and roan.

Pacing vs. Trotting

Standardbreds participate in harness racing as pacers or trotters. Pacers often wear hopples during the race to maintain the lateral gait, which is slightly faster than trotting.

Researchers have identified a single point mutation in the DMRT3 gene associated with the ability to pace. However, Standardbred pacers are still capable of trotting. All Standardbreds can perform other normal gaits, but cantering and galloping are penalized in harness races. [3]


Standardbreds have calmer dispositions than Thoroughbreds, thanks to the influence of other breeds in their development and the fact they receive much more formal daily exercise than Thoroughbreds. This makes them more suitable for all levels of riders after they are appropriately re-trained.

Most of these horses are also naturally people-oriented, friendly, and eager to please. Behavioural problems in Standardbreds often stem from poor handling or underlying health problems.


While all racehorses need adequate time and expert re-training to successfully transition to a second career, many Standardbreds have gone on to excel in other disciplines.

Their good dispositions and friendly personalities make them popular pleasure mounts for riders who enjoy bonding with their horse. Plus, the Standardbred’s strong hindlegs and hindquarters are well-suited for jumping, and the breed frequently appears in hunter/jumper arenas.

Downhill conformations may limit their talent for upper-level dressage, but many Standardbred owners enjoy competing at the lower levels. However, pacers may have more difficulty transitioning to sport horse careers than trotters because they prefer pacing to traditional gaits.

Standardbred Health

Standardbreds often struggle with similar health problems that afflict Thoroughbred racehorses. This breed also has a high incidence of developmental orthopedic diseases, but many Standardbreds can live exceptionally long lives with proper care.

Retired Racehorses

A racing career often involves frequent travel, limited turnout, repetitive training, extreme physical exertion, and high-energy diets. These lifestyle factors can increase stress and contribute to several health issues commonly seen in Standardbred and Thoroughbreds. [4]

Owners of recently retired harness racing Standardbreds should schedule a veterinary exam before beginning a re-training program. Otherwise, undiagnosed conditions could lead to behavioural problems and poor performance.

Health Problems

Gastric ulcers and other gastrointestinal conditions are significant concerns for Standardbreds. One study found gastric ulceration in 63.3% of actively racing Standardbreds. [5]

Research in Thoroughbreds also shows that racing increases the risk of gastric ulcers in horses. But poor digestive function isn’t the only health risk associated with racing. [15]

Physical exertion and rapid breathing during races can also lead to exercise-induced pulmonary hemorrhage (EIPH) or bleeding, which occurs when pulmonary blood vessels rupture in the lungs during exercise.

One survey of 60 Standardbreds reported that 87% of horses were positive for EIPH in at least one of three endoscopic evaluations after racing. Repetitive trauma to the lungs caused by EIPH can create scar tissue and reduce respiratory capacity in Standardbreds. [6]

Racing careers can also increase the risk of musculoskeletal injuries. While research suggests stress fractures are less common in harness racehorses than in Thoroughbreds, Standardbreds have a higher incidence of tendon and ligament injuries. [7]

Standardbreds are also susceptible to developmental orthopedic diseases. In a study of 464 Standardbred yearlings, researchers diagnosed bone lesions associated with osteochondrosis dissecans (OCD) in 50% of the horses. [8]

Diet, growth rate, and genetics can all contribute to OCD in horses, which can cause joint pain and poor performance in Standardbreds.

Care and Management

Standardbreds need basic care and management to ensure that their physical, mental, and social needs are met. Owners should work with their veterinarian to develop a preventative wellness program that includes vaccinations, deworming, and routine dental exams.

Although many Standardbreds live in stalls during their racing careers, providing your horse with adequate turnout and access to grazing helps reduce stress and ulcer risk. [9]

Freedom of movement during turnout also supports strong bones, tendons, ligaments and joints as well as reduced risk of stereotypic behaviours. Remember to introduce your Standardbred to turnout slowly if he isn’t used to being loose in a large field. [9]

Quality farrier care that maintains proper hoof balance will help to prevent excess loading forces from contributing to tendon and ligament injuries. Daily hoof picking and rel=”noopener” target=”_blank”>grooming supports healthy hooves, skin, and hair. [10]

Standardbreds are athletic horses that thrive with regular exercise. But light exercise might be more suitable if your Standardbred is a bleeder with reduced respiratory capacity from EIPH.

Nutrition Program

Good nutrition is the cornerstone of any horse care and management program. Standardbreds need a balanced diet with adequate forage to support gut health and overall well-being.

Weight Maintenance

Despite misconceptions that all horses bred for racing are hard keepers, most healthy Standardbred do not struggle to maintain weight. While Standardbreds descend from Thoroughbreds, they also have genetics from breeds considered easy keepers.

Research reveals that most Standardbreds with poor body condition have gastric ulcers. If your Standardbred loses weight on a balanced diet, contact your veterinarian to investigate a potential underlying medical problem. [5]

Sample Diet

Forage should be the foundation of your Standardbred’s diet. The average 1,000 pound (450 kg) Standardbred needs to eat at least 20 pounds (9 kg) of good-quality grass hay daily on a dry matter basis.

Providing constant access to free choice forage is the best way to support your horse’s digestive health and reduce ulcer risk. Horses that go long periods between meals have a higher risk of gastric ulcers.

Standardbreds often benefit from being fed alfalfa hay as an excellent source of dietary protein and calcium, which buffers gastric acid and prevent ulcers. However, too much alfalfa can throw off the calcium-to-phosphorous ratio in the diet. [13]

The following sample diet is intended for a mature Standardbred with normal body condition in light work.

Feed Diet
(Amount / Day)
Mid-Quality hay (10% crude protein) Free-choice
Salt 30 g (2 tbsp)
Omneity Pellets 200 g (2 scoops)
w-3 oil 60 ml (2 oz)
Diet Analysis
Digestible Energy (% of Req) 102%
Protein (% of Req) 142%
NSC (% Diet) 8.8%


Feeding Recommendations

Standardbreds have a lower risk of equine metabolic syndrome and insulin resistance compared to other breeds. Many of these horses can safely graze fresh pasture for most of the year without a grazing muzzle, but may need restricted pasture access when transitioning to grass in the spring.

Most Standardbreds do not need grain-based feeds to meet their energy requirements, but forage-only diets are usually deficient in certain amino acids, vitamins, and minerals. Nutrient deficiencies and imbalances can contribute to developmental orthopedic disorders and increase the risk of musculoskeletal injuries. [14]

Mad Barn’s Omneity, is comprehensive vitamin and mineral formula that can help to fill nutritional gaps and balance your Standardbred’s diet. Omneity provides all of the essential nutrients that your horse needs to support hoof health, coat quality, energy metabolism and more.

Omneity – Premix

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  • 100% organic trace minerals
  • Complete B-vitamin fortification
  • Optimal nutrition balance
  • Our best-selling equine vitamin

If your Standardbred needs more calories, add a fat supplement rather than feeding grains. Large high-grain meals have been implicated in gastric ulcers by contributing to damage to the mucosal lining of the stomach. [16]

In the sample diet, Mad Barn’s w-3 oil is used to meet calorie requirements and provide anti-inflammatory DHA to support joint health, exercise recovery and respiratory health, among other benefits.

Standardbreds also need constant access to fresh water and plain loose salt. We typically recommend adding 1 to 2 ounces of salt directly to their feed and providing loose, free-choice salt.

Nutritional Supplements

Nutritional supplements can provide targeted support for common health concerns and performance goals in Standardbred horses.

Standardbred owners should work with an equine nutritionist and submit their horse’s diet for a free evaluation to get personalized advice on their horse’s feeding program.

Gut Health

Given the high incidence of gastric ulcers in Standardbreds, it is important to feed a diet designed to reduce ulcer risk and to implement management practices to support gut health.

Visceral+ by Mad Barn can help maintain stomach and hindgut health in Standardbreds susceptible to gastrointestinal problems. This pelleted supplement contains probiotics, yeast, herbs, minerals, and amino acids that support the entire digestive tract.


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  • Our best-selling supplement
  • Maintain stomach & hindgut health
  • Supports the immune system
  • 100% safe & natural

Omega-3 Fatty Acids

Omega-3 fatty acids are generally recognized for their health-promoting effects and their ability to regulate inflammatory pathways in the horse’s body. Omega 3’s are commonly supplemented to support respiratory health, joint health, skin quality and coat shine.

Omega-3’s may be particularly beneficial for Standardbred racehorses with a history of bleeders. One study found omega-3 supplementation reduced EIPH in affected horses. [12]

Mad Barn’s W-3 Oil is a fat supplement that provides extra calories and essential fatty acids. This oil is high in Docosahexaenoic acid (DHA), an omega-3 fatty acid that support immune function, cardiovascular health, and joint mobility.

w-3 Oil

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  • Promotes joint comfort
  • Helps to fight inflammation
  • Skin & coat condition
  • Palatable source of Omega-3's

Joint Health

Standardbreds with a history of joint problems or soft tissue injuries may benefit from a joint supplement, such as MSM. This natural compound contains a bioavailable source of sulphur, a vital component of connective tissue, including glucosamine and collagen.


Standardbreds that are racing or participating in other work lose electrolytes through sweat during strenuous exercise or in hot weather.

Replenishing electrolytes is important for performance, muscle function, hydration status and more. Performance XL: Electrolytes is a scientifically balanced electrolyte designed for equine athletes to maintain top physical condition during high-performance sporting events.

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  1. Steele, D. Genesis of the Trotter. J Heredity. 1949.
  2. Adelman, M. The First Modern Sport in America: Harness Racing in New York City, 1825-1870. J Sport Hist. 1981.
  3. Jaderkvist, K. et al. The importance of the DMRT3 ‘Gait keeper’ mutation on riding traits and gaits in Standardbred and Icelandic horses. Livest Sci. 2015.
  4. Meleiro, M. et. Immune Functions Alterations Due to Racing Stress in Thoroughbred Horses. Animals (Basel). 2022. View Summary
  5. Dionne, R. et al. Gastric Ulcers in Standardbred Racehorses: Prevalence, Lesion Description, and Risk Factors. J Vet Intern Med. 2008.View Summary
  6. Lapointe, J. et al. A survey of exercise-induced pulmonary haemorrhage in Quebec Standardbred racehorses. Equine Vet J. 1994.View Summary
  7. Bertuglia, A. et al. Epidemiology of musculoskeletal injuries in a population of harness Standardbred racehorses in training. BMC Vet Res. 2014. View Summary
  8. Lykkjen, S. et al. Osteochondrosis and osteochondral fragments in Standardbred trotters: Prevalence and relationships. Equine Vet J. 2011. View Summary
  9. Lesimple, C. et al. Free movement: A key for welfare improvement in sport horses? Appl Anim Behav. 2020.
  10. Thompson, K. et al. The effect of toe angle on tendon, ligament and hoof wall strains in vitro. J Equine Vet Sci. 1993.
  11. Andrews, F. et al. Nutritional management of gastric ulceration. Equine Vet Ed. 2015.
  12. Erickson, H. et al. Review of Alternative Therapies for EIPH. J Appl Phys. 2001.
  13. Lybbert, T. et al. Feeding alfalfa hay to exercising horses reduces the severity of gastric squamous mucosal ulceration. Proceed AAEP. 2007.
  14. Buchholz-Bryant, M. et al. The effect of calcium and phosphorus supplementation, inactivity, and subsequent aerobic training on the mineral balance in young, mature, and aged horses. J Equine Vet Sci. 2001.
  15. Orsini, J.A. et al. Odds of moderate or severe gastric ulceration in racehorses receiving antiulcer medications. J Am Vet Med Assoc. 2003. View Summary
  16. Reese, R.E. and Andrews, F.M. Nutrition and Dietary Management of Equine Gastric Ulcer Syndrome. Vet Clin North Am: Equine Pract. 2009. View Summary