Short communication: Development of the first follicular wave dominant follicle on the ovary ipsilateral to the corpus luteum is associated with decreased conception rate in dairy cattle

Abstract

In this study, we examined the effect of the locations of the first-wave dominant follicle (DF) and corpus luteum (CL) on fertility. In total, 350 artificial insemination (AI) procedures were conducted (lactating dairy cows: n=238, dairy heifers: n=112). Ovulation was confirmed 24 h after AI. The locations of the first-wave DF and CL were examined 5 to 9d after AI using rectal palpation or transrectal ultrasonography. Lactating dairy cows and dairy heifers were divided into 2 groups: (1) the ipsilateral group (IG), in which the DF was ipsilateral to the CL; and (2) the contralateral group (CG), in which the DF was contralateral to the CL. Pregnancy was diagnosed using transrectal ultrasonography 40d after AI. Conception rates were 54.0% in all cattle: 48.9% in lactating dairy cows, and 58.9% in dairy heifers. The incidence of the first-wave DF location did not differ between IG and CG (all cattle: 184 vs. 166; lactating cows: 129 vs. 109; heifers: 55 vs. 57 for IG vs. CG). Conception rates were lower in IG than in CG (all cattle: 40.2 vs. 69.3%; lactating dairy cows: 38.0 vs. 67.0%; dairy heifers: 45.5 vs. 73.7%, for IG vs. CG). Conception rate was not affected by season or live weight in heifers and lactating cows. In addition, days in milk at AI, milk production, body condition score, and parity did not affect conception in lactating cows. In summary, development of the first-wave DF in the ovary ipsilateral to the CL was associated with reduced conception rates in both lactating cows and heifers.

Influence of ipsilateral coexistence of the first wave dominant follicle and corpus luteum on ovarian dynamics and plasma sex steroid hormone concentrations in lactating dairy cows treated with human chorionic gonadotropin

“…4 hCG treatment = Cows were treated with hCG (1500 IU) at five days from ovulation. 5 Day 5 = Ovulation day was defined as Day 1.…”

“…Previously, we have reported that the development of the first-wave DF ipsilateral to the corpus luteum (CL) was associated with reduced conception rates in lactating dairy cows [5] and the conception rate could be improved by administrating human chorionic gonadotropin (hCG) only to the cows having the first-wave DF ipsilateral to the CL at 5 days after artificial insemination (AI) [6]. However, we could not clarify the mechanism underlying the low fertility when the first-wave DF was ipsilateral to the CL and the physiological mechanisms of increasing conception rate by hCG treatment with the first-wave DF ipsilateral to the CL at 5 days after AI.…”

“…Plasma E 2 concentration of IG and CG in the non-treatment and the hCG treatment groups on Day 55 . IG = Ipsilateral group.…”

Relationship of the conception rate and the side (left or right) of preovulatory follicle location at artificial insemination in dairy heifers

“…In addition, the location frequency of contralateral relationship between the PF and CL is greater in heifers with the three follicular waves (Ginther et al 2014). In dairy heifers, the first-wave dominant follicle (DF) located ipsilateral to the CL in the ovary is associated with reduced conception rates (Miura et al 2015). Thus, it was possible that when the PF developed in the left ovary there was a high probability that the PF had developed from the third follicular wave; therefore, in this study, the conception rate may be higher when the PF developed in the left ovary.…”

“…However, the locational relationships among the PF, regressed CL and number of follicular waves were not confirmed in this study. In dairy heifers, the first-wave dominant follicle (DF) located ipsilateral to the CL in the ovary is associated with reduced conception rates (Miura et al 2015). Further research is required to clarify the mechanism underlying higher conception rates when the PF develops in the left ovary to confirm the relationships among the number of follicular waves, locational relationship of regressed CL and PF, and locational relationship of the first-wave DF and CL in dairy heifers.…”