Visual motility analysis is the basis for routine
quality evaluation of stallion semen, although its
prognostic value for fertilizing ability is considered low.
The present study evaluated the ability of a novel
computer-assisted motility analyzer (QualiSpermâ„¢) to
determine the motility and velocity of ejaculated,
extended stallion spermatozoa (collected from 10
stallions, 3 ejaculates/stallion) and following two
different colloidal centrifugation methods (one- or twolayer),
compared to visual evaluation by two
independent operators. The Qualispermâ„¢ instrument
was able to retrieve and analyze ~10 times more
spermatozoa per sample compared to routine visual
estimation on the same time frame (~1,100 vs ~100
spermatozoa). The proportion of motile spermatozoa
increased after the colloid-separation, compared to the
extended ejaculates (P < 0.05) in some stallions. However,
owing to the large variation seen among ejaculates and
stallions, both for extended ejaculate (P < 0.05) as well as
for the colloid centrifugations (P < 0.01), the differences
were lost when the entire population was examined
statistically. Interestingly, significant differences were
seen for individual stallions between the measurements
of Qualispermâ„¢ and observers, as well as between
observers (P < 0.05). Apart from the significantly higher
number of spermatozoa analyzed at one time, the
Qualispermâ„¢ system provided a parameter that could
simply not be estimated by visual assessment; mean
sperm velocity (in μm/sec). Sperm velocity, upon which
every computer assisted instrumentation base their
evaluations, varied among stallions (and ejaculates
within stallions, P < 0.05), with a tendency to increase
after colloid-separation, thus suggesting the
Qualispermâ„¢ system might be able to differentiate
sperm sub-populations. Due to its higher accuracy (in
terms of sperm numbers examined) and speed, the
Qualispermâ„¢ system appears to be a suitable
instrument for routine evaluation of equine semen.
