A meta-analysis of the Impact of Endometritis on Reproductive and Productive Performances of Lactating Dairy Herds

E ndometritis is a major postpartum disease that affects the productive and reproductive performance of dairy cows that is accompanied by heavy economic losses to the farmer. We conduct a meta-analysis to evaluate the effect of Endometritis on daily milk yield (DMY) and some reproductive indices (pregnancy rate, days open (DO), service per conception (S/C), and days to the first insemination) in lactating dairy cows. Data corresponding to 4037 cows was extracted from eleven research papers with suf-ficient data for analysis. The odds ratio was calculated for binary data (Endometritis incidence and pregnancy rate) by using the multinomial logistic regression, while the summary estimate was calculated for continuous data (DMY, S/C, and DO) by using the Linear mixed model (Multilevel regression). The odds ratio (OR) of Endometritis had a significant difference among different studies and years, paper No.4 recorded an equal number of diseased and healthy cows (OR=1), so we take this paper as a reference category, OR was the highest (1.6) for paper No.10, while it was the lowest (0.2) for paper No. 2. Concerning the pregnancy rate, Endometritis significantly reduced the pregnancy rate by 45% compared with the healthy cow. Regarding the DMY, Endometritis had a significant reduction in DMY by 1.7 kg rather than the healthy one. Concerning the DO, the cow that suffered from Endometritis had a more prolonged DO by 58 days than the healthy one, also S/C had a significant increase by 1.6 compared with healthy cows. Finally, we concluded that Endometritis had an adverse effect on the