What stage immediately precedes estrus?

The stage that immediately precedes estrus is proestrus. During proestrus, a number of physiological and behavioral changes occur that prepare the female animal for breeding. This stage is characterized by the development of the ovarian follicles, increased estrogen levels, and physical signs such as swelling of the vulva and a bloody vaginal discharge in some species like dogs.

Proestrus sets the stage for estrus, which is when the female is actually receptive to mating. Understanding this sequence is crucial for managing breeding schedules and ensuring the health and well-being of the animals involved. This knowledge also aids in recognizing the signs and stages of the reproductive cycle, which is vital for anyone working in veterinary settings or breeding programs.