view - Department of Reproduction, Obstetrics and Herd Health

SUMMARY
from stallions previously classified as unfreezable. Androcoll-E can be used with good results to select
a superior sperm population prior to cryopreservation, in order to produce good quality frozen
thawed semen.
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Based on the results presented in this thesis and reported data in literature, the following
conclusions can be put forward:
♦ Motility settings, necessary when performing computer assisted sperm analysis, influence the
motility outcomes to a great extent.
♦ The type of counting chamber used in combination with computer assisted sperm analysis has
an important effect on the concentration and motility results. Capillarity used for filling a
chamber restricts sperm motility severely.
♦ The present versions of the SQA-Ve are inefficient to univocally report on the quality of equine
semen. The device has a poor repeatability and very poor agreement with gold standard
methods to analyze sperm motility.
♦ Centrifugation protocol has a major influence on sperm yield. High centrifugation forces (up to
2400 × g) for a short time (5 min) can substantially reduce sperm losses without apparent
effect on in vitro sperm characteristics.
♦ Sperm selection using Androcoll-E in a single layer centrifugation technique prior to
cryopreservation, results in an overall increased sperm quality. This technique is promising for
clinical use because it enables cryopreservation of a subgroup of stallions previously deemed
as unfreezable.