Exploring the impacts of different antral follicle count and luteal presence on ovarian response and fertility in inseminated Boer does.

Antral follicle count (AFC) is considered a useful non-invasive method for providing valuable insights into a female's ovarian reserve. However, the influence of AFC and corpora lutea (CL) at the time of exogenous hormonal trigger (synchronization) on ovarian response to stimulation and fertility in goats remains unclear. This research aims to explore the impacts of different AFC and CL presence at the onset of hormonal synchronization (on Day 0) for fixed-time artificial insemination (fixed-time AI) on response to hormonal stimulation and fertility in Boer does. On Day 0, a transrectal ultrasound was performed to detect all visible antral follicle (AF; ≥ 2 mm) and CL. Based on AFC and CL, 128 does were divided into four groups in a 2 × 2 factorial trial (AFC I [≤ 3 follicles], AFC II [> 3 follicles], with CL [CL+], and without CL [CL-]): groups I (AFC I × CL+), II (AFC I × CL-), III (AFC II × CL+), and IV (AFC II × CL-). On Day 7, does were inseminated with cervical AI using the first dose of frozen thawed semen. On Day 7, there was no interaction between AFC and CL on all parameters of ovarian follicles. The follicle and reproductive parameters and ovarian responsive rate did not differ between CL+ and CL- does. Does with AFC > 3 follicles had a greater number of large AF (> 4 mm) and ovarian increased the responsive rate than does having AFC ≤ 3 follicles on their ovaries. The multiple kidding (twin kidding and triplet kidding) rate and fertility were superior for does having AFC > 3 follicles than does having AFC ≤ 3 follicles at the beginning of hormonal synchronization for fixed-time AI. Moreover, the likelihood of ovarian response to synchronization and multiple kidding increased by 3.03 and 4.09 times, respectively, in does with a greater total number of AF (AFC > 3 follicles) at the time of exogenous hormonal synchronization. Higher ovarian responses to stimulation and fertility are demonstrated by the previous appearance of more AFC available for selection into the ovulatory pool in poly-ovulatory does when performing hormonal synchronization for fixed-time AI.