What age chihuahua female first menstrual cicle?

A female Chihuahua typically experiences her first menstrual cycle, or estrus, between 6 to 12 months of age. However, this can vary depending on the individual dog and factors such as genetics and overall health. During this time, she may show signs of heat, including behavioral changes and discharge. It's important for owners to monitor their pets and consider spaying to prevent unwanted litters and health issues.