The best time to sterilize female cats is between 6 and 8 months old. Because female cats have an early estrus period, most of them will start to have estrus at six months. Therefore, if you do not plan to let the cat give birth, you can sterilize it this morning. Get your cat neutered. Neutering female cats can reduce uterine diseases, avoid howling during estrus, prolong life, and keep cats young in mind.