Effectiveness of lipopolysaccharide as an intrauterine immunomodulator in curing bacterial endometritis in repeat breeding cross-bred cows

Antibiotics are usually used to combat microbial infections of the uterus, responsible for hindering establishment of pregnancy in cross-bred cows. The major disadvantages of antibiotics are: development of bacterial resistance, high costs and diminishing uterine defense mechanisms (UDM). As an alternative therapy, intrauterine application of Escherichia coli Lipopolysaccharide (E. coli LPS) as a uterine defense stimulator was used in this study in confirmed clinical cases of repeat breeding associated with bacterial endometritis. In the treated group (n=12), on the day of estrus, 100 μg of E. coli LPS dissolved in 30-ml sterile phosphate buffer saline (PBS) was infused intrauterine; while in the control group (n=12), only 30 ml of PBS was infused. Six-hour post-treatment, in the treatment group uterine washings showed a 100-fold increase in the total leucocytic count (TLC). Out of the cellular contents, more than 80% of the cells were recognised as neutrophils; above 60% were alive and their phagocytic activity was five bacteria/neutrophil. Such a cellular response was maintained until 72-h post-treatment. At the subsequent estrus period, the cervicovaginal mucus (CVM) became clear in 9 out of 12 cows (75%) and showed no bacterial growth. In the control group, similar micro-organisms were present in CVM of all the 12 cows before and after the PBS infusions. During the subsequent estrus, all nine cows with sterile CVM in the treatment group conceived while only one cow conceived from the control group. It was concluded that, administration of intrauterine E. coli LPS as single infusion in cows with bacterial endometritis stimulated UDM and cleared the infection within one estrous cycle, and thereby restoring fertility.