The reproductive performance of lactating dairy cattle remains a major factor affecting herd’s profitability; estrous synchronization and timed artificial insemination (TAI) enable producers to maximize the reproductive efficiency of their herd. A total of 88 cows were used to measure the effect of mifepristone 0.4mg/kg with different doses of Buserelin (10µg, 20µg and 40µg/head) on estrous synchronization efficiency for the same period in cattle. Buserelin was injected at day 0-followed by PG (day=7)-Buserelin+ mifepristone (0.4mg/kg) (day=9) (BPBMH synchronization protocol), results revealed that Buserelin in 20µg dose has significantly (P < 0.05) increased estrus rate (86.96%) ovulation rate (82.61%) and conception rate (65.22%) among other doses when combined with mifepristone (0.4mg/kg dose) in cattle. A second experiment was designed to select the best time for FTAI, 95 cows were selected and treated with BPBMH in 0.4mg/kg mifepristone dose estrus synchronization protocol and timed artificial insemination was performed hrs16，20，24，28 and 32 after second GnRH. The results showed that artificial insemination at hrs 16 of mifepristone injection was the best insemination time in cattle. |
