Final answer:
It is generally false that the mare starts cycling by late November; horses are usually seasonally polyestrous. The statement about the menstrual cycle's first day is false; it marks the beginning of menstruation, not ovulation. The secretory phase aligning with the luteal phase is true.
Step-by-step explanation:
True or False: By late November the mare starts cycling and remains active through winter. This statement is generally False. Most horses are seasonally polyestrous, meaning they have multiple estrous cycles during specific seasons. Horses typically cycle from early spring to autumn and are anestrous during the winter months. However, certain management practices and artificial lighting can alter this natural cycle.
Day 1 of the menstrual cycle is when the secondary oocyte is released from its follicle. This statement is False. Day 1 of the menstrual cycle is actually marked by the start of menstruation. Ovulation, when the secondary oocyte is released, occurs midway through the cycle, around day 14 in a typical 28-day cycle.
The secretory phase of the uterine cycle generally aligns with the luteal phase of the ovarian cycle. This statement is True. The secretory phase is characterized by the preparation of the uterine lining for potential pregnancy post-ovulation and corresponds with the luteal phase when the corpus luteum is present in the ovary.