Pregnancy index of cows using progesterone after fixed-time artificial insemination

The objective was to evaluate the pregnancy rate using progesterone (P4) after 4 days of the FTAI. A total of 126 multiparous cows were used. The experimental design was completely randomized, with two treatments (T1 and T2), being: T1 -Control and T2 -P4 injectable D14. The cows were submitted to the same hormonal protocol of 3 treatments until the day of the FTAI, differentiating only in the D14. After 40 days of FTAI, the following pregnancy rates were obtained: T1-55.6% and T2-49.20%. It is concluded that the use of progesterone after 4 days of AI does not show differences of conception rate in relation to the control group and its use reduces the profitability of the productive system.