Both male and female dogs and cats are mature enough to reproduce between the ages of six to nine months. Female dogs generally go through an estrus or heat cycle every six months. This is accompanied by a proestrus or bleeding cycle prior to her true heat cycle in which she is very receptive to the advances of male dogs. This heat cycle may last for several days or up to three or four weeks. Often female dogs will experience some personality changes during heat cycles such as becoming short-tempered or anxious.
Female cats come into heat cycles every three to four weeks during certain times of the year.
Many female cats will become nervous during these heat cycles and exhibit unusual behaviors such as rolling on the floor, furtively hiding, or wanting constant attention. Female cats often become quite vocal, too, meowing plaintively through their cycle. Surgical neutering of female dogs and cats called ovariohysterectomy, completely eliminates all heat cycles and the accompanying unwanted bleeding cycle, nervousness, and desire to mate. Neutering your female dog or cat will also protect your pet from uterine infections and other diseases as well as difficult or dangerous pregnancies. Studies show that by neutering your female dog before her first heat cycle, you can greatly reduce her chances of developing mammary cancer later in life.