Effect of Uterine Bacterial Infection during Postpartum on Reproductive Efficiency in Cross-bred Dairy Cows

Abstract

This study was designed to determine the intensity of bacterial load in the uteri of postpartum (PP) dairy cows, and the effects of this uterine bacterial infection on some of their reproductive traits. Six reproductive traits were evaluated: uterine involution (UI), appearance of the first dominant follicle (DF), recrudescence of the first oestrus (FO), length of the days open (DO), calving interval (CI) and the rate of service per conception. Uterine endometrial swabs were collected on day 5 PP from 130 dairy cows and cultured within 2 hours of collection onto blood agar and MacConkey agar media. The uteri of 120 cows (93%) were infected. From the total infected cows, 40 were used to evaluate the effect of bacterial uterine infection on their reproductive performance. Twenty cows were severely infected and the remaining 20 were mildly infected. The results showed that dairy cows suffering severe uterine bacterial infection had a significantly (P≤0.001) extended uterine involution period, long time for the appearance of the first DF and FO, length of DO and CI compared with the dairy cows that suffered mild uterine bacterial infection. Moreover, the dairy cows which suffered severe uterine bacterial infection had a significantly (P≤0.001) increased rate of service per conception compared with the cows with mild uterine bacterial infection. It is concluded that the reduced reproductive efficiency of crossbred dairy cows in the Sudan is likely to be due to early PP uterine bacterial infection