Meeting Abstract
P3.95 Sunday, Jan. 6 Functional morphology in modern horses: natural vs. artificial selection MCHORSE, BK*; HOPKINS, SSB; DAVIS, EB; University of Oregon; University of Oregon; University of Oregon bmchorse@uoregon.edu
Functional morphology plays an important role in modern sport horse purchase and breeding decisions. Conformation, or the skeletal proportions of the animal, is considered a reliable indicator of athletic ability and long-term resistance to injury. Despite the influence of conformation assessments on equine breeding and trade, few studies have used analytical methods to establish quantitative relationships between conformation and performance in artificially-selected competition horses, and none have examined the differences between domestic breeds and the feral mustang. Existing work suggests a significant relationship between judgments of quality and conformational variables, especially shoulder and pelvis angle, which influence the reach and timing of stride. We investigated the conformation-performance correlation in eventing, an equestrian discipline that tests the ability of the horse to complete three unique phases. We conducted the same measurements on extant mustangs, which are under natural selective pressures. Results suggest a significant relationship between conformational variables and competition scores; however, the characters that predict performance in eventing are not exactly the same as those that distinguish between the morphology of mustangs and performance horses. Higher performance correlates with a shorter back, longer neck, shorter metapodials, and a sloping pelvis. Mustangs tend to differ from domestic breeds in their generally smaller size and more compact structure, as well as having a narrower range of variation in conformational traits. These results show the need for caution when using domestic horses in evolutionary studies. Mustangs, even if domesticated after ranging as part of a feral herd, may be a more appropriate group to use when exploring the evolutionary history and patterns of horses.
