Pet owner need to decide whether to castrate the male Shih Tzu or spay your female Shih Tzu. Female Shih Tzu normally come in heat when it reach six months, it will come every six months or depend on its family genetics.
To reduce the chance of develop mammary (breast) cancer in later stage, we better spay our female Shih Tzu before its first estrous cycle. It can prevents testricular prostate, ovarian and uterine diseases.
There are so many unwanted dogs on street, early surgical neutering can prevents unwanted pregnancies. When female Shih Tzu is in heat, it always attract neighborhood dogs or her estrus vaginal bleeding can stain your home carpets or furniture.
Early surgical neutering will not affect food intake, growth rate or weight gain of your Shih Tzu.