Assistant Laboratory Animal Technician (ALAT) Practice Exam 2026 – Complete All-in-One Guide to Exam Success!

The phase during which the female animal becomes receptive to mating is known as estrus. During this phase, also referred to as "heat," various physiological and behavioral changes occur that signal the female's readiness to mate. This includes an increase in pheromones and changes in vulvar swelling, which attract males.

In contrast, anestrus is a period of inactivity in the reproductive cycle when the female is not receptive to mating. Pregnancy is a state in which the female is carrying offspring and generally does not exhibit mating behavior. Lactation refers to the period during which a female produces milk for her offspring, and while some females may come into heat during this time, they are typically less receptive compared to when they are in estrus. Therefore, estrus is the definitive phase indicating receptivity to mating and is characterized by significant changes that facilitate reproduction.