Effects of FSH treatment and withdrawal during proestrus on uterine proliferation and steroid hormone receptor expression in beef heifers

To determine the effects of Follicle Stimulating Hormone (FSH) treatment and subsequent withdrawal on uterine proliferation and estrogen receptor (ESR), Brahman crossbred heifers (n = 12) were twice daily injected with FSH (4, 3, and 2 mg/injection) on Days 17–19 of the estrous cycle (FSH 3 days) and (4 and 3 mg/injection) on Days 17–18 (FSH 2 days) and withdrawal with saline on Day 19 and (4 mg/injection) on Day 17 (FSH 1 day) and withdrawal with saline on Days 18–19. Uterine tissue was subjectively collected on Day 20 and microscopically classified to four regions: endometrial stroma (ES), surface endometrial gland (EG), deep endometrial gland (DG), and myometrium (Myo). The cell proliferation marker, Ki-67, was quantified as labeling index (LI) in uterine regions, and tissues were immunostained to detect ESR2 followed by image analysis. The LI of ES, EG, and DG was greater (P = 0.0018, P = 0.0005, and P = 0.0103; respectively) in heifers received FSH for 3 days. The expression of ESR2 protein on ES and EG was greatest (P < 0.0001 and P = 0.0036, respectively) in FSH 3 days-treated group. Thus, FSH administration during proestrus stimulates uterine cell proliferation, and ESR2 expressions are affected by FSH during proestrus and differentially distributed in the uterine regions.     

Estrous and ovulatory responses following cervical artificial insemination in Thai-native goats given a new or once-used controlled internal drug release with human chorionic gonadotropin

The study was conducted to compare estrous rate, ovulatory response, plasma progesterone concentrations, and conception rate following cervical artificial insemination in goats given a new or once-used controlled internal drug release (CIDR) device with human chorionic gonadotropin (hCG). Fifty-six Thai-native goats with the average age and body weight of 11 months and 17.3 kg received a 14-day treatment with a new CIDR device (Eazi-Breed^TMCIDR®, Pfizer, NY, USA) or a once-used CIDR device. All goats received a 300-IU injection of hCG (Chorulon®, Intervet International B.V., New Zealand) at the day of CIDR removal to induce ovulation. All goats displaying signs of Estrous behavior were artificially inseminated at 12 h after the onset of estrus with frozen semen. No differences in percentage of estrus and ovulation rates were observed; however, goats that received once-used CIDR devices exhibited shorter (P?P?>?0.05) between treatments during CIDR device insertion and at the time of CIDR removal except on day 4. No significant differences were found in overall conception rates between the treatments. This study indicates that the once-used CIDR device with hCG could be applied to synchronize the estrus and ovulation in small-size Thai-native goats without negative effects on Estrous behavior, ovulatory response, and plasma P4 concentration.