A high incidence (about 70%) of alteration in endometrial epidermal growth factor
(EGF) profile, i.e., loss of 2 peaks on days 2–4 and 13–14, has been linked to a
reduced fertility in multiparous repeat breeder Holstein cows. However, the EGF
profile in Holstein heifers and other breeds (types) of cattle has not been
investigated. In study 1, EGF concentrations were determined using endometrial
tissues obtained by biopsy on days 3, 7 and 14 from 84 fertile Holstein heifers to
obtain a normal range and 53 repeat breeder Holstein heifers to estimate incidence of
alterations in the EGF profile. In repeat breeder heifers, EGF concentrations were
similar to fertile controls on 3 days and five animals (9.4%) had an altered EGF
profile with EGF concentrations below the normal range on days 3 and 14. In study 2,
EGF concentrations on day 3 were repeatedly examined from the nulliparous period to
the third postpartum period in 28 Holstein (dairy) and 47 Japanese Black (beef)
cattle. The effect of parity on EGF concentrations on day 3 was different between
Holstein and Japanese Black cattle. In Japanese Black cows, the EGF concentrations
were consistently high throughout the study period, while in Holstein cows, the EGF
concentrations decreased after the second calving. In conclusion, unlike multiparous
repeat breeder Holstein cows, an altered EGF profile may not be a major cause of
repeat breeding in Holstein heifers, and the peak EGF concentrations around day 3 may
decrease even in fertile populations of multiparous dairy cows, but not in beef
cows.