Fluctuations of antimüllerian hormone, ovarian follicular reserve, and antioxidant status throughout the estrous cycle in aged mares.

Background: Senility influences fertility in women and companion animals, especially horses.

Aim: This study aimed to investigate the effect of aging in horses on the daily changes in the dominant follicle (DF) dynamics and hemodynamics, antimüllerian hormone (AMH), enzymes, antioxidants, and ovarian hormones during the estrous cycle.

Methods: Ovaries of old mares ( = 5, age >20 years) and young native mares ( = 6, age <10 years) were scanned during 6 different estrous cycles from March 2022 to August 2023 with Doppler ultrasound.

Effect of hCG and prostaglandin on ovarian, luteal development, and hormonal changes in embryo donor mares during the hot summer months in subtropics.

Background: Commercial embryo flushing of horses has required hormonal management of both the donor and recipient mares throughout the breeding season.

Aim: This study aimed to find out the effect of using human chorionic gonadotropin (hCG) and prostaglandin F2α (PG) on the ovarian and uterine dynamics and hemodynamics, estradiol (E2), progesterone, oxidants-antioxidants, and blood biochemicals in embryo donor mares during the hottest months of the year in a subtropical climate.

Methods: Three Control estrous cycles of native mares (10-20 years; = 10) followed by two treated cycles with hCG and PGF2α were examined daily from May to August using Doppler ultrasound with blood sampling.

Effect of breeding season and age on follicular dynamics and hemodynamics in embryo donor mares subjected to luteolysis after embryo flushing.

Background: Mares are the only companion animals simulating women in the large diameter of their follicles. Horses start reproduction at the age of three years, and some of them live for >30 years, so aging influences their reproductive capacity. Mares are sensitive to summer heat stress as they can sweat like humans.