Evidence-based medicine: quality and comparability of clinical trials investigating the efficacy of prostaglandin F2α for the treatment of bovine endometritis

The objective of this study was to evaluate the quality and comparability of published literature, and to summarize the effect of prostaglandin F-2 alpha (PGF(2 alpha)) for the treatment of endometritis. It has been postulated that there is a dearth of high-level evidence-based research results in veterinary medicine. Also, there is a marked variation in the quality of studies in veterinary and animal science. Postpartum uterine infections occur commonly in dairy cattle and are reported to have a negative impact on reproductive performance. A comprehensive literature search was conducted utilizing online databases revealing a total of 2723 references. After applying specific exclusion criteria, a total of 68 trials were eligible for further analysis. These articles were evaluated utilizing specific parameters listed in an evaluation form such as randomization and the involvement of control groups. The analysis revealed that more than half of the trials (51.5%) were at least 20 years old. Furthermore, we found that about one third (36.8%) of all trials were controlled and randomized, while 3 of those (4.4%) were also blinded. Of those trials which calculated a calving-to-conception interval (n=30), 50% of the authors claimed an improvement, which was statistically significant in 23.3% of the cases. We conclude that there is a wide discrepancy between research results investigating the efficacy of PGF(2 alpha).