Abstract

Repeat breeding is a common reproductive problem in cattle and has a significant impact on production efficiency and economic losses in livestock farming. This disorder is characterized by repeated failure to conceive despite normal estrous cycles and proper artificial insemination techniques. One of the main causes frequently reported to be associated with repeat breeding is endometritis, particularly subclinical endometritis, which often goes undetected through conventional clinical examination. Subclinical endometritis is characterized by inflammation of the endometrium without obvious clinical symptoms, but it can modify the intrauterine environment, thus inhibiting fertilization, early embryo development, and embryo implantation. This review aims to comprehensively examine and synthesize recent scientific findings related to the contribution of endometritis to repeat breeding in cattle. Discussions include the concept and classification of repeat breeding and endometritis, the pathogenic mechanisms involving colonization and persistence of pathogens in the uterus, the endometrial inflammatory response, and hormonal imbalances that impact corpus luteum function and embryo implantation success. Furthermore, various predisposing factors contributing to the development of endometritis, such as management practices, nutritional and metabolic status, and individual characteristics of the cow, are systematically described. Various diagnostic methods, ranging from clinical evaluation, endometrial cytology, reproductive system ultrasonography, to microbiological and molecular approaches, are also discussed as a basis for determining appropriate management strategies. This article also highlights therapeutic options and preventive measures focused on improving reproductive health and controlling the risk of antimicrobial resistance. Overall, endometritis plays a significant role in the occurrence of repeat breeding in cattle, making early detection and the implementation of integrated reproductive management key to improving fertility rates and livestock production efficiency.

Key words: Cattle; Endometritis; Fertility; Repeat breeding; Subclinical.