title: Does cleansing of frozen-thawed bull semen before assessment provide samples that relate better to potential fertility?
abstract: The present study estimated, in vitro, the influence of two cleansing methods on sperm parameters post-thaw and their relation to the fertility of the frozen-thawed semen after AI. Frozen semen from six 1-year-old Swedish Red and White dairy bulls with a range in fertility (as 56d-Non-Return Rates, i.e., 56d-NRR) of 62.2-70.7% among batches was tested, using three batches of semen per bull. From each batch, individual straws were analyzed immediately after thawing (PT, control) or pooled and subjected to a swim-up procedure (SU) or washing by centrifugation/re-suspension (W) prior to in vitro assessments. Subjective and computerized measurements of sperm motility and of concentration, morphology, and membrane integrity were recorded. SU provided spermatozoa with significantly better motility, acrosome-, midpiece- and tail morphology and membrane integrity compared to either control or W treatment. Significant, albeit low, correlations among single sperm parameters and NRR were found (after PT for tail abnormalities (r = 0.49) and average path velocity, VAP (r = 0.47), after SU for total sperm motility with CASA (r = 0.50) and after W only for non-linear motility (r = -0.69)). SU of frozen-thawed bull semen is a simple preparation procedure that selects for sperm motility and membrane integrity, essential parameters for fertilization. It helps in vitro assessment of the semen and provides a significant, although low, relationship to the fertility of the assayed semen.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences (SLU), Ullsvägen 14C, Clinical Centre, P.O. Box 7039, Ultuna SE-750 07, Uppsala, Sweden.
authors.forename: Triin
authors.initials: T
authors.lastname: Hallap
authors.forename: Margareta
authors.initials: M
authors.lastname: Håård
authors.forename: Ulle
authors.initials: U
authors.lastname: Jaakma
authors.forename: Birgitta
authors.initials: B
authors.lastname: Larsson
authors.forename: Heriberto
authors.initials: H
authors.lastname: Rodriguez-Martinez
mesh_terms: D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000648:ultrastructure; D002498:Centrifugation; D015925:Cryopreservation / Q000662:veterinary*; D005298:Fertility; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D012662:Semen Preservation / Q000662:veterinary*; D013048:Specimen Handling / Q000379:methods / Q000662:veterinary*; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000002:abnormalities / Q000648:ultrastructure