RT Journal Article T1 Optimization of the Equine-Sperm Freeze Test in Purebred Spanish Horses by Incorporating Colloidal Centrifugation A1 Bláquez Sarro, Juan Carlos A1 Gutiérrez Cepeda, Luna A1 Crespo Castejón, Francisco A1 Serres Dalmau, María Consolacion AB The Purebred Spanish Horse, according to our clinical experience, is characterized by having a high number of stallions that do not meet the international commercial recommendations forequine-sperm cryopreservation. This means that artificial insemination with frozen semen from these stallions is less widespread than in other breeds. In this study, we investigated if the incorporation ofsingle-layer colloidal centrifugation prior to cryopreservation in clinical conditions could increase the number of ejaculates of Purebred Spanish stallions suitable for this processing, observing the influence of centrifugation and freezing extender protocol on post-thawed sperm motility. Using colloidal centrifugation, the percentage of ejaculates available to be frozen was increased from 35% (6/17) to71% (12/17), doubling the number of samples that could have been subjected to cryopreservation. We only found significant differences in linearity (LIN) and lateral head displacement (ALH) after5 min of incubation at 37 ◦C between colloidal and simple centrifugation processing techniques. No significant differences were found between the two different colloidal protocols in any of the variables considered. Colloidal centrifugation allowed us to obtain, from worse fresh-quality ejaculates, thawed sperm doses with similar quality to that of good-quality ejaculates. BotuCrio® produced, in general higher motility parameters and its characteristics than the other extenders analyzed, with significant differences found in comparison to Inra-Freeze® and Lac-Edta in both total (MOT) and progressive motility (PMOT) when using colloidal centrifugation and only in PMOT when applying simple centrifugation. Colloidal centrifugation optimized the efficiency of cryopreservation, as it allowed usto increase the number of ejaculates of Purebred Spanish Horses suitable to be frozen. Including these semen processing techniques in the freeze test could help to optimize equine-sperm cryopreservation protocols, especially when dealing with individuals or breeds for which initially low sperm quality prevents or limits their inclusion in sperm cryopreservation programs PB MDPI SN 2076-2615 YR 2022 FD 2022-01-22 LK https://hdl.handle.net/20.500.14352/97316 UL https://hdl.handle.net/20.500.14352/97316 LA eng NO Gutiérrez-Cepeda L, Crespo F, Blazquez JC, Serres C. Optimization of the Equine-Sperm Freeze Test in Purebred Spanish Horses by Incorporating Colloidal Centrifugation. Animals (Basel). 2023 Jan 22;13(3):382. NO MICINN DS Docta Complutense RD 18 jul 2024