The Role of Light Progression in the Hormonal Sequence of the Mare’s Estrous Cycle, describe the sequence of hormones beginning with those affected by increasing day length that: Bring a mare into estrous and then to ovulation The hormone sequence of the mare’s estrous cycle is driven by the progression of increasing day length. As the days become longer, the mare is affected by changes in the hormones that ultimately bring her into estrous and then to ovulation. In the mare’s estrous cycle, the initial hormones affected by increasing day length are the hypothalamic hormones, GnRH and kisspeptin. GnRH is a hormone produced by the hypothalamus that stimulates the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland (Munoz-Cueto et al., 2020). Kisspeptin, another hypothalamic hormone, acts in the hypothalamus to stimulate GnRH secretion (Zhao et al., 2017). This hormone cascade leads to a surge in LH, which is the primary hormone responsible for the mare’s receptiveness to breeding. The LH surge triggers the mare’s estrous cycle and leads to the ovulatory follicle becoming the dominant follicle in the ovary (Robinson et al., 2016). As the LH surge continues, the dominant follicle produces increasing amounts of progesterone, which is essential for the mare’s receptiveness to breeding. Cont….

The Role of Light Progression in the Hormonal Sequence of the Mare’s Estrous Cycle

The hormone sequence of the mare’s estrous cycle is driven by the progression of increasing day length. As the days become longer, the mare is affected by changes in the hormones that ultimately bring her into estrous and then to ovulation. In the mare’s estrous cycle, the initial hormones affected by increasing day length are the hypothalamic hormones, GnRH and kisspeptin. GnRH is a hormone produced by the hypothalamus that stimulates the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland (Munoz-Cueto et al., 2020). Kisspeptin, another hypothalamic hormone, acts in the hypothalamus to stimulate GnRH secretion (Zhao et al., 2017). This hormone cascade leads to a surge in LH, which is the primary hormone responsible for the mare’s receptiveness to breeding. The LH surge triggers the mare’s estrous cycle and leads to the ovulatory follicle becoming the dominant follicle in the ovary (Robinson et al., 2016). As the LH surge continues, the dominant follicle produces increasing amounts of progesterone, which is essential for the mare’s receptiveness to breeding. Cont….