Low Incidence of an Altered Endometrial Epidermal Growth Factor (EGF) Profile in Repeat Breeder Holstein Heifers and Differential Effect of Parity on the EGF Profile Between Fertile Holstein (Dairy) and Japanese Black (Beef) Cattle

Abstract

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.

Endometrial epidermal growth factor profile and its abnormalities in dairy cows

“…The normalization of the EGF profile resulted in the restoration of fertility in RB cows [3, 5]. Thus, these findings support the existence of a potential relationship between the endometrial EGF profile and fertility [1, 3]. …”

“…In the present study, increased EGF concentrations were observed between Days 2 and 5 in individual cows, and the mean EGF concentrations exhibited an apparent peak on Days 3 and 4. Minor differences in the timing of the first peak found in the 2 studies might not affect the interpretation of our previous findings on the role of altered EGF profiles on reduced fertility in RB and high-yielding dairy cows [1,2,3, 5, 7]. Rather, these results might improve the reliability of our previous studies since these studies used the endometrial EGF concentrations on Day 3 to evaluate the first peak.…”

“…The technique elicits no or negligible effects on the cyclicity [18,19,20] and fertility [7, 17] of cows. Repeated biopsy allows us to collect endometrial samples daily or more frequently during the estrous cycle in the same animals, significantly reducing the number of animals to be sacrificed for sampling.…”

“…Epidermal growth factor (EGF) concentrations in the uterine endometrium exhibit a cyclic change during the estrous cycle, and the loss of a cyclic EGF profile, in the presence of an apparently normal estrous (ovarian) cycle, may reduce fertility in dairy cows [1]. In normal cows, endometrial EGF concentrations peak twice on Days 2–4 and 13–14 with reduced EGF concentrations around Day 7, whereas the 2 peaks in the endometrial EGF profile are not observed in approximately 70% of repeat breeder (RB) Holstein cows [2, 3].…”

Effect of seminal plasma infusion into the vagina on the normalization of endometrial epidermal growth factor concentrations and fertility in repeat breeder dairy cows

“…Studies on the regulation of EGF in the uteri of mice and rats have found that estrogen is the primary regulator of EGF production in the endometrium [2][3][4][5]. In fertile cows, the endometrial EGF concentrations in the uterine endometrium show two peaks at days 2-4 and 13-14 of the estrous cycle, and the loss of these peaks, even in the presence of an apparently normal estrous (ovarian) cycle, indicates a reduction of fertility in dairy cows [6][7][8]. These peaks were not found in about 70% of Holstein repeat breeder cows and 25% of Holstein cows 60 days postpartum [6,8].…”