Figure 1 (Roth et al. 2021.)

Positioning of the linear measurements. Abbreviations are indicated in Table 3 below. 

Traits that are selected for in American Quarter Horses vary based on which discipline the horse is bred for. Different linear traits, such as measurements, are used when determining which mare would best suit a stallion who's proven to be skilled in the discipline. 

Horses with longer, slower strides are typically found to be more favorable to people who are looking for western horses. However, horses who can cover more ground quicker are mostly bred for the hunter under saddle discipline.  

This selection of features is what determines what breeders prefer to see in their produced horses. They also try to find a balance between the mare and the stallion to produce a better baby than its parents. 

Table 3 (Roth et al. 2021.)

Statistical analysis of Traits by Riding Discipline on the QH, Western Pleasure (WPL), Hunter under Saddle (HUS), and Reining (RN). 

According to the results, of the 24 variable measurements taken, 15 showed significant differences when compared to the horse's selected discipline (Roth et al. 2021). Six variables in particular showed significant differences among all three tested disciplines, which were, Height at Withers, Height at Croup, Topline, Underline, Height of Carpal Joint, and Length of Cannon Bone Forelimb. All acronyms that were found significant appear on Figure 1 above. 

These differences show us that there are distinct anatomical differences when it comes to what the horse was selectively bred for. Breeders specifically look for these traits in a stallion and mare to benefit the breed and create a better baby. 

Since selective breeding chooses preferred traits over less preferred traits artificially rather than naturally, no natural selection can occur. Natural selection in a species can take a long time to occur, but selectively breeding an animal is much faster and can give breeders exactly what they want in a horse.  

Introductory video to VS Code Red, known as "Waylon" around the barn, and his lineage of champions. 

The Million Dollar Sire

VS Code Red

VS Code Red has made a huge name in the Quarter Horse industry due to how breeders select their studs to breed with their mares. He is one of several examples of studs to choose from in the Quarter Horse breeding umbrella. His lineage is known to be very successful, so naturally, breeders choose him as a guaranteed line of success. 

Quarter Horse Characteristics

Utah State University Equine Intern, Makenna Osborne, maps out the common traits found in the American Quarter Horse Breed.