Abstract
Background:
Sperm sexing is a critical technique in livestock breeding, used to select offspring of a desired sex. This study investigates an alternative to traditional methods like flow cytometry by utilizing freeze-dried albumin as a medium for sperm separation in Bali bulls, a breed with significant economic importance in Indonesia.

Aim:
The aim of this study was to evaluate the efficacy of freeze-dried albumin compared to fresh albumin in sperm sexing, focusing on its impact on sperm separation, quality preservation, and kinematic properties.

Methods:
Fresh semen from Bali bulls was processed using two different sperm separation media: fresh albumin and freeze-dried albumin. The sperm motility, viability, membrane integrity, acrosome integrity, and kinematic parameters (e.g., velocity, linearity) were measured and compared between the two mediums. The proportions of X- and Y-chromosome-bearing sperm in the separated fractions were also assessed.

Results:
The study found no significant difference in sperm quality parameters (motility, viability, etc.) between the two mediums. However, freeze-dried albumin resulted in higher separation efficiency, with a greater proportion of X-bearing sperm in the upper gradient layer compared to fresh albumin. Kinematic analysis indicated slightly improved motility and stability in sperm treated with freeze-dried albumin.

Conclusion:
Freeze-dried albumin is a viable alternative to fresh albumin for sperm sexing, offering superior separation efficiency while maintaining sperm quality. Its advantages in stability, ease of storage, and cost-effectiveness make it an ideal choice for resource-limited settings, potentially advancing reproductive biotechnology in livestock breeding.

Key words: Albumin freeze-dried, Bali bull, Kinematic, Medium, Sexing, Sperm