The objective of present study was investigate the relationship between ovarian antral follicle count (AFC), serum alkaline phosphatase (ALP), alanine transferase (ALT), aspartate amino transferase (AST), progesterone and cortisol; and fertility to develop the selection tools for improve the reproductive performance of buffaloes. Antral follicle count (AFC) used as a basic indicator for selection. 21 non-pregnant, cyclic buffaloes were monitored AFC using ultrasonography. Scanning of the ovaries was performed on day 3 and day 5 of estrus and blood samples were collected from 3-5 day during early luteal phase (EL) and 13-15 day of estrus, during luteal phase (L) for measuring serum ALP, ALT, AST, progesterone and cortisol. Counting of AFC based on antral follicle with (≥3mm) in diameter, animals divided into high group G1 (≥ 9 AFC) and low group G2 (< 9 AFC). The results indicated that, the main values of days open were lower in G1 (70.30) than in G2 (103.38) and number of services per conception were lower in G1 (1.3) than G2 (2.57) respectively. Differences weresignificant (P≤ 0.001). Blood serum Levels of progesterone concentration were higher in EL and L with G1 (0.53 and 4.31 ng/ml) than G2 (0.19 and 1.69 ng/ml), while levels of cortisol concentration were lower in EL and L with G1 (1.32 and 1.52 µg/dl) than G2 (1.97 and 2.33 µg/dl) respectively. Differences were significant (P≤ 0.001). Blood serum Levels of ALP concentration were lower in EL and L with G1 (121.66 and 138.56 u/l) than G2 (165.79 and 185.5 u/l) respectively. Also, the levels of AST concentration were lower in EL and L with G1 (42.94 and 47.48 u/l) than G2 (53.41 and 59.36 u/l) respectively. While, the levels of ALT concentration were higher in EL and L with G1 (26.66 and 23.43 u/l) than G2 (22.44
and 20.43 u/l) respectively. Differences were significant (P≤ 0.001). In conclusion, there was a positive relationship between high AFC and good fertility parameters or high fertility. Also high levels of blood serum concentration of (progesterone
and ALT) were associated with a good fertility parameters or high fertility. On the other hand high levels of blood serum concentration of (cortisol, ALP and AST) were associated with the weak fertility parameters or low fertility. So that AFC, progesterone, cortisol, ALP, ALT and AST could be an important indicators for selection female buffaloes with high reproductive performance.