The effect of intensive flunixin treatment during the postpartum period in the bovine.

The aim of this study was to determine the effect of flunixin meglumine (FM), a substance which inhibits the prostaglandin biosynthesis, on the uterine involution. One of the characteristics of the postpartum period in cattle is the massive and extended release of prostaglandin (PG) F2 alpha. Eleven primiparous cows, divided into three groups, were included in the study. The first group was injected with FM four times daily, the second group twice daily and the third group acted as controls. The dose was 2.2 mg/kg body weight injected intramuscularly. The treatment period was 14 days beginning at parturition. Blood samples were collected prior to calving and up to 28 days postpartum. The plasma concentrations of the main circulating PGF2 alpha metabolite, i.e. 15-keto-dihydro-PGF2 alpha, and progesterone were analysed. The involution of the uterus was assessed by rectal palpation and ultrasonography. The study showed that it was not possible to affect the time period to completed uterine involution, not even when a very intensive drug dosage was used. A statistical difference was found between the group receiving the most intensive treatment and the controls, when the areas under the prostaglandin metabolite curve (AUC) were compared. The PG synthesis and release were decreased by the treatment, but never totally suppressed. Even though the treatment with FM did not shorten the time to completed uterine involution, it was not detrimental for the process of involution. However, as the uterine involution is an inflammatory process, flunixin could, as an anti-inflammatory drug, be beneficial under certain circumstances.