SEMEN COLLECTION, EVALUATION AND CRYOPRESERVATION OF ARABIAN EQUINE STALLIONS

Abstract

        The purpose of this study was to evaluate the macroscopic and microscopic characteristics of fresh and cryopreserved semen from Arabian stallions. Semen was collected once a week for six weeks from two healthy adult stallions between October and April 2025. Macroscopic evaluation included ejaculate volume, color, and consistency, while microscopic assessment focused on sperm motility, viability, and morphology. Ejaculates were extended using a glucose–sodium citrate extender, diluted at a 1:1 ratio based on sperm concentration, and cryopreserved in 0.25-mL plastic straws. Straws were subsequently thawed at 37°C for 30 seconds for post-thaw evaluation.

Results revealed that fresh ejaculate characteristics varied as follows: 25.0 ± 1.63% to 35.0 ± 2.9% for sperm motility, 63.0 ± 2.9% to 78.0 ± 4.6% for viability, 56.0 ± 3.1% to 78.0 ± 4.2% for plasma membrane integrity, and 52.0 ± 1.9% to 71.0 ± 3.8% for acrosome integrity. The mean total sperm abnormality ranged from 8.00 ± 0.47% to 22.0 ± 1.4%, with tail and head abnormalities ranging from 4.0 ± 0.07% to 18.0 ± 0.96% and 3.0 ± 0.06% to 14.0 ± 0.78%, respectively. After thawing, highly significant differences were observed, with progressive motility, live sperm, and acrosome integrity reaching 45.83 ± 2.01%, 68.17 ± 1.78%, and 63.17 ± 1.64%, respectively. The mean total ejaculate volume was 60 mL. Morphometrically, the total length of normal stallion sperm was approximately 55.0 ± 0.004 \(\mu \)m, comprising a head length of 5.69 ± 0.004 \(\mu \)m, head breadth of 4.06 ± 0.004 \(\mu \)m, midpiece length of 8.17 ± 0.008 \(\mu \)m, and tail length of 48.0 ± 0.021 \(\mu \)m.

In conclusion, cryopreservation of Arabian stallion semen yields optimal post-thaw quality across all evaluated parameters when utilizing a glucose–sodium citrate extender at a 1:1 dilution rate.