Racehorses are getting faster
Wilson, Alastair J.
This is the author's post print version of the article.
Reason for embargo
Previous studies have concluded that thoroughbred racehorse speed is improving very slowly, if at all, despite heritable variation for performance and putatively intensive selective breeding. This has led to the suggestion that racehorses have reached a selection limit. However, previous studies have been limited, focussing only on the winning times of a few elite races run over middle and long distances, and failing to account for potentially confounding factors. Using a much larger dataset covering the full range of race distances and accounting for variation in factors such as ground softness, we show that improvement is in fact on-going for the population as a whole, but driven largely by increasing speed in sprint races. In contrast, speed over middle and long distances, at least at the elite level, appears to be reaching an asymptote. Whether this reflects a selection limit to speed over middle and long distances or a shift in breeding practices to target sprint performances remains to be determined.
BBSRC David Phillips Fellowship
Data used for analyses in this manuscript are available in Dryad: http://dx.doi.org/10.5061/dryad.qn82p.
Copyright © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Published online 24 June 2015