Influence of puerperal metritis on the first ovulation after calving in dairy cows.

The aim of this study was to determine how puerperal metritis influences the resumption of estrous cycle in dairy cows. The ovaries of 72 multiparous Holstein cows (38 healthy and 34 metritic - after treatment) were ultrasonographically scanned until the first ovulation postpartum and 7 days after to confirm the ovulation. All 72 cows were divided in to 4 groups: HSO (healthy with single ovulation) (n=29), MSO (metritic with single ovulation) (n=21), HDO (healthy with double ovulation) (n=9), and MDO (metritic with double ovulation) (n=13). The proportion of cows that had DO in the first ovulation postpartum was similar between M and H groups, 38.2% and 23.6%, respectively (p>0.05). There was a difference between HDO and MDO groups comparing the first dominant follicle ovulation postpartum (11.4±2.7 and 20±1 days, respectively p⟨0.05) and the diameter of the ovulatory follicles (15.3±1.9 mm and 17.3±1.7 mm, respectively p0.05). The percentage of cows that had double follicle dominance in the first follicular wave after first ovulation was higher in the M groups (33.3% (MSO) vs. 6.9% (HSO) (p⟨0.05) and (69.2% (MDO) vs. 22.2% (HDO) (p⟨0.05)). The MSO group dominant follicle diameter was bigger for cows which had one dominant follicle (p⟨0.05). It might be concluded that dairy cows after puerperal metritis need more time until the first ovulation. Also, metritic cows have a higher risk for double dominance in the first follicular wave, after the first ovulation.