"Heat cycle" refers to the process of a system or object going through a series of heating and cooling stages. It is the repetitive pattern of heating up and then cooling down that occurs over time. Full definition
We recommend that your pet is spayed / neutered around 4 - 6 months of age, before the first heat cycle of the female cat or dog. (petsfriendsunnyvale.com)
This helps to avoid the inconvenience of heat cycles in females and provides health and social benefits to both males and females. (plainfieldanimalhospital.com)
Often, female dogs will experience some personality changes during heat cycles, such as becoming short - tempered or anxious. (pmcofedmond.com)