TheHorse.com - Full Article
By Christa Lesté-Lasserre, MA
Nov 1, 2017
When it comes to breeding good endurance horses, many traits aren’t heritable or have little to do with performance. But French researchers said one feature does matter: the heart.
“An ‘athletic’ heart is a heritable characteristic that’s favorable for performance in endurance,” said Céline Robert, PhD, DVM, professor and researcher at the National Veterinary School of Maisons-Alfort and researcher at the French National Agricultural Research Institute in Jouy-en-Josas, France.
Unlike Thoroughbred racehorses, Arabian and Arabian-cross endurance horses start training at around age 4 or 5 and reach high-level (160-kilometer) races starting at about 8 years old. “If you have to invest eight years of training and maintenance into a horse before you know if you’ve got a champion, you want to be sure you’re starting off with the right horse,” Robert said.
But success doesn’t always pass down through the genes. That’s why Roberts and her fellow researchers set out to determine what genetic factors affect performance and how heritable they are.
They found that most measurable traits—whether related to morphology, gaits, or cardiology—have little to do with success on endurance rides. And that’s consistent with her 2014 findings, which were limited to morphology alone.
“Few traits are related to performance, and few of those have strong heritability,” she said.
However, several heart parameters did appear to affect performance and were also more or less heritable. The most significant were related to the size of the left ventricle and the volume of blood ejection...
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