Background: The assessment of seminal quality parameters is often the initial step in bull selection for siring or conservation purposes. While these parameters provide insights into fertility, delving into the molecular dynamics occurring within sperm cells can complement this primary reproductive evaluation. Cholesterol, one of the most active molecules on the sperm membrane surface, has been linked to critical processes that confer functional features required for reaching the oocyte and achieving fertilization. The complexity of cholesterol dynamics in the sperm surface, including membrane lipid remodeling, is relevant to numerous processes that precede fertilization. 

Objective: To elucidate the correlation between sperm quality parameters and cholesterol levels in sperm cells from Chino-Santandereano bulls, a Colombian creole breed renowned for its high sperm quality, yet unfortunately facing imminent extinction. 

Methods: Semen samples were collected from ten Chino-Santandereano bulls to evaluate sperm motility, viability, and sperm functional competence (SFC) immediately after collection. Simultaneously, cholesterol was extracted from sperm membranes using a methanol-chloroform solution, and cholesterol levels were measured by spectrophotometry using a specific commercial kit. A Pearson's correlation test was used to determine the relationship between cholesterol concentration and seminal quality parameters. 

Results: Our results revealed a strong negative correlation between cholesterol quantity and the average SFC. Additionally, cholesterol levels were also negatively associated with sperm motility. This suggests that cholesterol dynamics, particularly cholesterol output, play a more significant role in sperm functionality than cholesterol content.

 Conclusions: Monitoring cholesterol output from the sperm membrane appears to be an interesting alternative to complement the initial reproductive evaluation in bulls. The intricate nature of these relationships deserves further experimental work to fully comprehend the implications of cholesterol for the reproductive potential of Chino-Santandereano bulls’ semen and offer insights for enhancing sperm quality in other breeds.