Editing Swayback (section)

==Horses==
[[File:Swayback3.jpg|thumb|A horse with significant swayback]]
Usually called "swayback", soft back, or low back, an excessive downward bend in the [[back (horse)|back]] is an undesirable [[equine conformation|conformation]] trait. Swayback is caused in part from a loss of muscle tone in both the back and abdominal muscles, plus a weakening and stretching of the ligaments. As in humans, it may be influenced by bearing young; it is sometimes seen in a [[broodmare]] that has had multiple foals.  However, it is also common in older horses whose age leads to loss of muscle tone and stretched ligaments. It also occurs due to overuse or injury to the muscles and ligaments from excess work or loads, or from premature [[working animal|work]] placed upon an immature animal. Equines with too long a [[back (horse)|back]] are more prone to the condition than those with a short back, but as a longer back is also linked to smoother [[horse gait|gaits]], the trait is sometimes encouraged by [[selective breeding]].  It has been found to have a hereditary basis in the [[American Saddlebred]] breed, transmitted via a [[Dominance relationship|recessive gene]].<ref name="K.E.R"/> Research into the genetics underlying the condition has several values beyond just the Saddlebred breed as it may "serve as a model for investigating congenital skeletal deformities in horses and other species."<ref>[http://www.thehorse.com/ViewArticle.aspx?ID=17422 Oke, Stacey. "Genetics of Swayback in Saddlebred Horses Examined"  ''The Horse'' online edition, December 20, 2010. Accessed December 21, 2010]</ref><!--cite covers hereditary piece-->