Resegregation of Ideal Square Horse Phenotype

Free-roaming horses in North America are living history, evidence of how human and horses have interacted with each other and the environment over last five hundred years. That history includes many instances of out-crossing of free-roaming Colonial Spanish stock. The US Cavalry Remount programs encouraged ranchers to run registered Thoroughbred stallions from the 1800’s until the demise of the American Cavalry after WWII. Federal policy towards Native American populations included castration and/or slaughter of war-ponies and the purposeful introduction of draft and harness stallions to reservations.

Unfortunately, the resegregation of horses with ideal Square or Colonial Spanish type out of unknown or mixed ancestry has not been studied. Documenting the history and progeny of horses of ideal Colonial Spanish type from varied backgrounds would offer windows into maintaining type, genetic diversity, fertility and health. Recognizing such horses would result in a wealth of information and goodwill, both direly needed if these horses are to thrive.

DR. Sponenburg has completed DNA testing for Robert Painter’s herd as it is dispersed after Painter’s death. Painter kept excellent breeding records while he bred Colonial Spanish horses for what he defined as Barb Type, specifically the 90o angles at the hip and shoulder typical of the Square Horse. That included experimenting with a cross to G’Danc Har, a Square stallion registered with one of the Arabian registries.


The results of testing the entire Painter herd can help illuminate the question of re-segregation of ideal Square Horse type. If Painter’s stringent selection for type over 5 decades has resulted in a breeding population of horses with genetic markers that are within the parameters of Iberian/Barb horses, that indicates that selecting for ideal type can result in a predictable genetic fingerprint.

Colonial Spanish horses have distinctive conformational features typical of animals that have evolved to thrive in high, dry and cold climates with rugged terrain. Despite the introduction of Thoroughbred and harness horses, small populations of phenotypical and genotypical Square or Colonial Spanish horses continue to appear in the wild. Documenting those horse’s genetics offers a wealth of information. Test available now include:

  • MtDNA results
  • Y chromosome DNA results
  • Presence of Iberian/Barb genetic markers
  • Degree of homozygosity
  • Tests for known genetic disorders
  • gait genetics (diagonal/lateral)
  • genetic tests for color, height, endurance, etc would also be informative.

Free-roaming horses of ideal Square Horse phenotype from historical free roaming populations of horses appear among:

  • BLM horses
  • Herds on other Federally managed lands, including military and National Parks
  • free roaming horses from State lands
  • Indian Reservation horses
  • Private Rancher’s horses

The Nokota horses of traditional type have been evaluated by blood typing, and the results indicate that the outwardly traditional, Spanish, type is still being occasionally produced from the general mix of Teddy Roosevelt National Park Horses. This is an interesting finding, although at odds with the experience in other herds where a traditional Spanish type tends not to resegregate once lost.

These findings make the Nokota horse (traditional type) a very difficult issue, because they are appropriate for type, but it is a genetic resegregation of that type. They are clearly out of the mainstream of conservation of the Colonial Spanish Horse, and really cannot be considered useful for the conservation of Colonial Spanish Horses.’ DR Phil Spoonenburg 7/11

Regrettably, fragmentation and contention among Colonial Spanish horse registries has resulted in losing track of a devastatingly large percentage of breeding stock. Some Colonial Spanish Barb Mustang etc… breeders have integrated Sorraia, Paso, PRE, Lusitano, Lippizaner, Criollo or Maghreb Barb horses into established ‘purpose-bred’ herds. Working Equitation, Trail and Endurance as well as the booming interest in ‘sport-ponies’ also offers Colonial Spanish stallion owners a new market and opportunity to promote the breed.

Because there are so few mares available in these small endangered populations, please understand that I am NOT encouraging half-bred foals from Colonial Spanish mares!

Studying horses of ideal phenotype from such crosses would, again, offer tremendous depth of information as well as help build goodwill. Providing evidence of each Square Horse’s functional soundness under saddle would increase credibility. Documenting that the horse has performed while barefoot, while carrying 20-25% of their own body weight and traditionally completed while eating only grass would give breeders, trainers and owners goals to strive for. Standardized tests of functional soundness include:

  • Kikkuli 4 Day Culling Protocol
  • Kikkuli 266 Day Conditioning Protocol
  • Criollo Registries two week La Marche Endurance test

By learning more about the genetics of horses that display ideal Colonial Spanish type and abilities under saddle regardless of their background, breeders and researchers may eventually be able to help breeders maintain genetic diversity and reproductive health as well as functional soundness well into the future generations of these horses.

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