Use of a five-day progesterone-based timed AI protocol to determine if flunixin meglumine improves pregnancy per timed AI in dairy heifers

In Experiment 1, 248 heifers were assigned randomly to either the PGF2α/GnRH protocol (n = 120) or the 5 d Co-Synch + CIDR protocol (n = 128). Pregnancy per TAI did not differ between the 5 d Co-Synch + CIDR protocol (53.1%) and the PGF2α/GnRH protocol (45.8%; P = 0.22). In Experiment 2, 325 heifers synchronized with the 5 d Co-Synch + CIDR protocol were assigned randomly to receive two injections of FM (FM group; n = 158) at 15.5 and 16 d after TAI, or to remain as untreated controls (n = 165). Pregnancy per TAI in Experiment 2 was 59.4 and 59.5% at 45 d for control and FM groups, respectively, with no differences between groups (P = 0.83). The 5 d Co-Synch + CIDR protocol resulted in an acceptable P/TAI in dairy heifers. However, FM did not improve P/TAI in dairy heifers.