Sperm Quality in Cryopreserved Holstein Friesian Bull Semen and Bacterial Load as Affected by Different Extenders

This study compared the effects of two different types of extenders, tris aminomethane egg yolk and modified trico egg yolk, on sperm quality after thawing and bacterial load in cryopreserved semen from a Holstein Friesian bull. Semen samples were divided into two treatment groups, each consisting of five semen tubes (0.25 ml), which were frozen using either Tris aminomethane egg yolk extender or modified trico egg yolk extender. Post-thaw evaluation included sperm motility, viability, abnormalities, membrane and acrosome integrity, capacitation status, DNA fragmentation, sperm kinematics, and bacterial load. Data were analyzed using the Wilcoxon test, while bacterial content was analyzed descriptively. The results showed that Tris aminomethane extender had higher sperm quality parameters after thawing compared to Trico egg yolk extender. Specifically, Tris aminomethane is higher than trico egg yolk in motility (48.20%), viability (68.10%), intact acrosome integrity (70.36%), and membrane integrity (67.92%). Additionally, significantly higher values were observed in parameters related to sperm kinematics, including Curvilinear Distance (DCL, 62.22%), Curvilinear Velocity (VCL, 155.06%), and Amplitude of Lateral Head (ALH, 8.97%). Meanwhile, the trico egg yolk extender caused significantly higher values in sperm straightness (STR, 84.02%), linearity (LIN, 56.22%), and wobble (WOB, 65.40%). The content of E. coli and Mycoplasma bacteria was higher in the trico extender, while Staphylococcus was more dominant in the tris aminomethane extender. These findings indicate that both extenders can maintain the quality of frozen sperm. The results of this study indicate that the Trico egg yolk extender is a reasonable and cost-effective alternative, with comparable performance in several sperm quality parameters; however, the effectiveness of bacterial inhibition needs to be reevaluated in relation to the antibiotic dosage used.