A New Approach to Repeat Breeding in Cows: Treatments Targeting the Endometrial Growth Factor-cytokine Network

Repeat breeder (RB) cows have been reported to have an alteration in ovarian steroid concentrations in the circulation. The endocrine alteration disturbs the endometrial growth factor-cytokine network in the endometrium and, in turn, may cause embryonic death in RB cows. An example may be loss of peaks in the cyclic change of epidermal growth factor (EGF) concentrations in the endometrium. This alteration of the EGF profile can be found in 70% of RB cows in high yielding dairy herds. Hormonal treatment with a high dose of oestradiol and infusion of seminal plasma normalizes the endometrial EGF profile and restored fertility. The treatments targeting the endometrial regulatory network may become an effective option to deal with RB cows.