This finding lends
credence to previous reports suggesting sperm motility, by
itself, is not a good predictor of fertility achieved by
inseminating mares with frozen-thawed, cooled, or fresh
equine semen [9-13]. While these investigators did not all
state that, they did show higher correlations with 2
(sometimes more) sperm parameter measurements and
fertility compared to correlations of fertility to sperm
motility alone. Justification for this opinion was based on
the concept that predicting actual fertility of a semen
sample based on in vitro analyses is unrealistic because
many factors other than semen quality affect fertility [13]
and that sperm must possess many attributes, not just
motility, to successfully fertilize an oocyte [12].