Assistant Laboratory Animal Technician (ALAT) Practice Exam

How often do female mice come into estrus?

1. Once every 2 to 3 days

2. Once every 4 to 5 days

3. Once every week

4. Once every 10 days

The correct answer is: Once every 4 to 5 days

Female mice typically experience estrous cycles, which are characterized by recurring phases of reproductive readiness. The estrous cycle in mice is usually around 4 to 5 days long. During this period, female mice will go through different stages, including proestrus, estrus, metestrus, and diestrus, with the estrus stage being the time when they are most receptive to mating. This understanding of the estrous cycle duration is critical for various aspects of laboratory animal management, including breeding, experimental design, and overall animal welfare. Accurate knowledge of when female mice are in estrus allows for optimal timing in breeding programs and effective management of research protocols reliant on reproductive cycles. While female mice might indeed cycle more frequently than once a week, a cycle every 2 to 3 days would suggest a shorter than normal cycle length. Conversely, cycles extending to every week or longer are less typical for most strains of laboratory mice as they usually do not align with the standard estrous cycle frequency observed in these animals.