Changes in EGF concentrations during estrous cycle in bovine endometrium and their alterations in repeat breeder cows.

The objective of the present study was to determine if abnormalities in the cyclic changes of endometrial EGF concentrations can be a diagnostic tool for repeat breeder cows. First, the profile of EGF concentrations during the estrous cycle was determined using endometrial tissues obtained from 31 Holstein cows after slaughter. Cyclic cows had two peaks of EGF concentrations. Then, endometrial tissues were obtained from 12 control and 20 repeat breeder cows by biopsy on Days 3, 7, and 14 of the same estrous cycle. Endometrial EGF concentrations in biopsied samples of the controls were similar to those found in slaughterhouse materials; they were high on Days 3 and 14 (9.2 and 10.4 ng/g tissue, respectively) and low on Day 7 (3.8 ng/g tissue). Concentrations of EGF in repeat breeder cows had a different profile; they were similar on Days 3, 7, and 14 (4.4, 3.4, and 4.0 ng/g tissue, respectively). In conclusion, changes in endometrial EGF concentrations were altered in repeat breeders; these alterations may be a potential diagnostic marker for repeat breeder cows.