Effects of progesterone concentrations and follicular wave during growth of the ovulatory follicle on conceptus and endometrial transcriptome in dairy cows

Abstract

Objectives were to evaluate the effects of follicular wave and progesterone concentration on growth of the ovulatory follicle, conceptus elongation, uterine IFN-τ concentration, and transcriptome of conceptus and endometrium of pregnant cows on d 17 of gestation. Nonlactating nonpregnant Holstein cows were assigned randomly to one of 3 treatments: ovulation of a firstwave follicle (FW, n = 15); ovulation of a first-wave follicle and progesterone supplementation (FWP4, n = 12); and ovulation of a second-wave follicle (SW, n = 19). Ovulation of a first-or second-wave follicle was achieved by initiating the Ovsynch protocol (d −9 GnRH, d −2 and −1 PGF 2α , d 0 GnRH and artificial insemination, d 0.7 artificial insemination) on d 0 or 6 of a presynchronized estrous cycle, respectively. Cows in FWP4 received 3 intravaginal inserts containing progesterone at 12, 24, and 48 h after the first GnRH injection that were removed on d −2. Cows were killed on d 17 for collection of the reproductive tract. Transcriptome was evaluated by microarray using the Affymetrix Bovine Array. Orthogonal contrasts were built to assess the effects of progesterone concentration during follicle growth (FW vs. FWP4 + SW) and follicular wave (FWP4 vs. SW). Progesterone concentrations (LSM ± SEM) from d −9 to −2 were greater for SW, followed by FWP4 and FW (5.38 ± 0.24, 4.26 ± 0.28, and 1.17 ± 0.27 ng/mL). Diameter of the ovulatory follicle (FW = 19.6 ± 0.6; FWP4 = 15.6 ± 0.6; SW = 15.2 ± 0.5 mm) and concentrations of estradiol from d −2 to 1 (FW = 4.05 ± 0.33; FWP4 = 2.73 ± 0.35; SW = 2.48 ± 0.30 pg/mL) were greater for FW compared with FWP4 and SW. Progesterone concentrations from d 3 to 16 were greater for FW compared with FWP4 and SW. A total of 28 singleton conceptuses were collected (FW, n = 8; FWP4, n = 8; SW, n = 12) and only intact conceptuses were included in the analyses of length (FW, n = 8; FWP4, n = 6; SW, n = 12). Although conceptuses were longer for FW compared with FWP4 and SW (FW = 16.6 ± 2.3; FWP4 = 9.8 ± 2.2; SW = 9.6 ± 2.0 cm), treatment did not affect the amount of IFN-τ in uterine flushing. Transcriptome of conceptuses and endometrium of pregnant cows was not extensively affected by follicular wave (8 and 1 differentially expressed transcripts) or concentration of progesterone during follicle growth (0 and 3 differentially expressed transcripts), showing that these factors did not affect conceptuses and endometrium transcriptome in pregnancies that are maintained to d 17.

The fertility of dairy heifers and cows is not influenced by the follicular wave of the ovulatory follicle

“…(2022) recently observed a longer conceptus on day 17 after insemination in FFW than SFW lactating cows. In addition, the follicular wave did not affect the IFN-τ concentration in the recovered uterine flush and the transcriptome of conceptuses of pregnant cows [ 21 ]. Longer conceptuses and higher amounts of IFN-τ in the uterine flush have frequently been considered as a sign of continuing pregnancy and higher fertility [ 32 , 33 , 34 ].…”

“…This is in accordance with the findings reported by Bisinitto et al . (2022) that an earlier and faster increase in serum progesterone was evident by day 14 after artificial insemination in FFW cows than in SFW cows based on daily measurements of serum progesterone [ 21 ]. Nevertheless, the mechanisms involved in fertility imposed by follicular wave require further research.…”

“…The size of the largest ovulatory follicle on the day of estrus and the size and volume of the corpus luteum (CL) on day 10 after estrus were determined using transrectal ultrasonography. The width and height of the CL and its cavity were measured at the largest cross-section and the volume of the CL was determined using the following formula: average radiuses were used for calculation of the CL volume as (4.3 × π × R 3 CL ) – (4.3 × π × R 3 Cavity ), where R CL is the average radius of the CL, R cavity is the average radius of the cavity, and π = 3.14159 [ 21 ]. In cases where there were two ovulatory follicles or corpora lutea in the ovary, the mean size and volume were recorded.…”

Efecto en la eficiente reproductiva mediante el uso de dos protocolos (eCG y Ovsynch) para IATF en ganado bovino tropical

“…Asimismo, Otava et al (2021) indican que, la necesidad de inseminar el mayor número de animales en un período relativamente corto de tiempo implica desarrollar protocolos que permitan sincronizar el retorno al estro de los vientres que resultaron vacíos a la inseminación a tiempo fijo (IATF) (Otava et al, 2021). Resultados de programas de IATF indican que es posible obtener porcentajes de preñez promedio del 50% a la primera inseminación, tanto en vacas con cría como en novillas; al respecto Bisinotto et al (2022) agregan que existen y se han aplicado protocolos para vacas con cría con los cuales resulta un incremento de los porcentajes de preñez. Los dispositivos intravaginales pueden ser reutilizados debido a que la cantidad hormonal en ellos está dada por gramos y la cantidad que las vacas necesitan para poder entrar en calor es en nano gramos, de esta forma la concentración residual de progesterona de un DIB de tercer uso podría ser capaz de inducir una sincronización de calores con similar tasa de gestación, cuando este se utiliza en novillas (Martins et al, 2021).…”

Whole genome-wide analysis of DEP family members in sheep (Ovis aries) reveals their potential roles in regulating lactation

“…Previous reports suggest that some DEP proteins can regulate lactation [23][24][25][26]. However, systematic studies of the roles of sheep DEP family members in regulating lactation are currently lacking.…”