Inflammatory uterine microenvironment in long-term infertility repeat breeder cows compared with normal fertile cows.

The reproductive performance of lactating dairy cows is gradually declining, and one of the causes of this problem is the presence of long-term infertility repeat breeder cows (RBCs). The causes of RBCs are largely thought to be maternal factors, including the uterine environment. This study aimed to accurately investigate the uterine environment of RBCs using uterine tissue and fluid.