Variation in Uterine and Serum Proteins During the Reproductive Cycle in Dairy Cows Following Low and High Dietary Protein Intake.

OBJECTIVES

This study aimed to investigate the correlation between dietary protein levels and the concentrations of various proteins in blood serum and uterine fluid during different stages of the reproductive cycle in dairy cows.

MATERIALS AND

METHODS

Forty Holstein cows, all 45 days postpartum, were randomly assigned to two groups: one receiving a diet containing 16% protein, and the other 19% protein. After a 14-day adaptation period, oestrus synchronization was performed using the Heatsynch protocol. Cows were fed total mixed rations (TMR) three times daily, adjusted based on weight and age. Blood and uterine fluid samples were collected at different stages of the reproductive cycle and analysed for total protein, albumin and globulin fractions (alpha-1, alpha-2, beta-1, beta-2 and gamma globulin).

RESULTS

Cows receiving the 19% protein diet exhibited significantly higher uterine fluid total protein levels across all cycle phases (p < 0.05), and increased uterine albumin during proestrus, oestrus and metestrus. In serum, alpha-1-globulin was higher in the 19% group during oestrus and metestrus, whereas alpha-2-, beta-1-, beta-2- and gamma-globulins were generally higher in the 16% group at specific phases (p < 0.05). Pearson correlations revealed stage-specific relationships between serum and uterine proteins, with alpha-2-globulin and gamma-globulin showing opposing correlation patterns during dioestrus. No significant differences were observed in fertility or pregnancy rates between treatments.

CONCLUSION

Higher dietary protein levels appear to influence reproductive parameters in dairy cows by altering protein profiles in blood and uterine fluid. These findings highlight the role of dietary management in optimizing reproductive health and performance.