Reproductive Efficiency following Administration of an Inhibitor of Prostaglandin F_2α during Early Embryonic Development in Dairy Cattle

A study was performed to examine the administration of flunixin meglumine (FM; an inhibitor of prostaglandin F_2α) following artificial insemination on pregnancy rates of lactating dairy cattle. Jersey and Holstein cows (n=106) were randomly assigned to receive intravenously either FM (2.2 mg/kg BW) or saline (SAL; 1 mL/23 kg BW). Cows were randomly allotted to treatment by lactation number, bovine somatotropin administration, breed, BW, days in milk, milk production, and 305 ME milk production. Study was performed from September through April and all cows were milked twice daily. Following estrous synchronization (cloprostenol, 500 µg im), cows were artificially inseminated 12 ± 6 h after the onset of estrus was detected utilizing electronic monitoring. Administration of FM or SAL was administered 5 d ± 12 h following artificial insemination. Animals underwent verification of pregnancy 28-35 d following artificial insemination using transrectal ultrasonography by an individual blinded to treatment. Pregnancy was determined by the presence or absence of an embryo with a heartbeat. Pregnancy data were analyzed using CRD Mixed ANOVA Analysis. Administration of FM following artificial insemination did not improve pregnancy rates in lactating dairy cows (FM, 37 vs SAL, 31.4%; P > 0.10). In conclusion, treatment with flunixin meglumine did not improve pregnancy rates when administered following artificial insemination in lactating dairy cows.