Answer:
Gestation, parturition, and lactation are essential processes in mammalian reproduction, including horses, cows, sheep, and pigs. The gestation period ranges from 115 to 123 days in horses, 279 to 287 days in cows, 145 to 155 days in sheep, and 114 days in pigs. During gestation, the fetus develops in the uterus, and the placenta provides nutrients and oxygen to support the growing embryo.
Parturition, or giving birth, begins when the fetus reaches full term and is ready to be born. The onset of labor is triggered by hormonal changes, which cause the uterus to contract and the cervix to dilate. During birth, the fetus passes through the birth canal, and the umbilical cord is broken.
Lactation, or milk production, begins after parturition when the hormone prolactin stimulates the mammary glands to produce milk. The milk provides essential nutrients and antibodies to the newborn. The suckling reflex in the newborn stimulates milk letdown, and milk is released from the mammary glands for the offspring to consume.
Across species, the processes of gestation, parturition, and lactation share similarities. Hormonal changes trigger parturition, and lactation provides essential nutrients and antibodies to the newborns. However, there are differences in the duration of gestation, the number of offspring per litter, and the duration of lactation. Understanding these processes is crucial for animal husbandry and ensuring the health and welfare of both the mother and offspring.