Assistant Laboratory Animal Technician (ALAT) Practice Exam

What is the term for coming into heat 24 hours after giving birth?

1. Postpartum estrus

2. Anestrus

3. Proestrus

4. Estrus cycle

The correct answer is: Postpartum estrus

The correct term for coming into heat 24 hours after giving birth is postpartum estrus. This phenomenon occurs in some species, particularly in certain rodents like mice and rats, where females can exhibit reproductive readiness shortly after delivering offspring. This early return to estrus is an adaptive strategy that allows for the possibility of another litter to be conceived while still caring for the existing young. In this context, postpartum estrus plays an essential role in maximizing reproductive success in species with high offspring mortality. Other cycles like anestrus, proestrus, and the estrus cycle represent different stages of the reproductive physiology but do not specifically refer to the return to heat immediately after parturition. Anestrus refers to a period where the animal is not in a reproductive state, proestrus is the preparatory stage leading up to estrus, and an estrus cycle encompasses the entire reproductive cycle itself, comprising several phases including estrus, but does not pinpoint the timing directly after giving birth.