Abstract. This research was conducted to investigate the correlation between blood metabolic
and reproductive performance on the Holstein-Friesian crossbred. Twenty cows on the second
to the third lactation were used in this research. The blood was collected through a jugular
vein, eight hours after feeding; it was used for investigating serum protein, glucose, and
estradiol. The reproduction including service per conception (S/C), postpartum mating (PPM),
and calving interval (CI). The data were analyzed using the Pearson Correlation Model. The
average of serum protein, glucose, and estradiol concentration were 7.17±0.86 g/dl; 56.14±4.56
mg/dl; and 4.97±0.75 pg/mL respectively. The average of PPM, CI, and S/C were
150.40±69.85 d; 433.60±106.01 d; and 1.6±0.75 t respectively. The results showed that the
correlation coefficient of the estradiol on serum protein and serum glucose were 0.309 and
0.329 respectively. The correlation coefficient of serum protein on PPM, S/C, and CI were -
0.096; –0.333; -0.134 respectively. While that of serum glucose on PPM, S/C, and CI were -
0.109; –0.327; and -0.309 respectively. Serum protein and glucose had a negative correlation
on S/C, PPM and CI.