Semen extender triggers a mild physiological inflammatory response in the uterus without disrupting sperm-uterine immune crosstalk in vitro in cattle.

Artificial insemination (AI) in cattle involves introducing frozen-thawed sperm, a minimal amount of seminal plasma, and a significant volume of semen extender (SE) into the uterus. Previous studies have demonstrated that sperm interacts with bovine endometrial epithelia via TLR 2/1, triggering a weak inflammatory response to clear the endometrium. This study investigated the impact of the major component of the insemination dose, egg yolk-based SE, on the uterine immune response in vitro.