Why spay your dog?

Why spay your dog - From the Sunrise Side Veterinary Hospital

Why spay your female dog ? You don’t plan to breed her and you watch her when she is in heat, right? You make sure there is no chance of pregnancy ?
Well… here is a size comparison for you. Here are two sets: uterus/Fallopian tubes/ovaries from two different, 60 lb dogs. The smaller of the two has just come close to entering the first heat cycle and the other has had about six or so heat cycles.
As you can see, size comparison/vasculature are quite different. The more heat cycles with pregnancies or not, significantly increases many risks including: cystic growths, mammary cancer/infected uterus/false pregnancies/uterine cancer/hormonal behavioral issues/etc.
Females who are spayed before their first heat cycle have less than 0.5% chance of developing mammary cancer. This percent increases quite significantly to 26% for pets spayed after only two heat cycles. The more heat cycles the pet goes through the higher the risk of these cancers.
Spaying your female:
Eliminates the risk of uterine and ovarian cancer, while significantly lowering the risk of mammary cancer
Stops unwanted pregnancies and over population
Ends the risk for a uterine infection or life threatening emergent situation called a pyometra. Pyometras are very common for in-tact female dogs and the current studies show that up to a quarter of intact females will develop an infection in their uterus by the age of ten.
Spaying also stops unwanted heat cycles, roaming, and hormone fluctuations that can cause false pregnancies.
Edit to add: there do come exceptions and special cases where a delay in spaying is recommended especially with larger breed dogs/depending veterinarian’s recommendations for specific conditions/cases/breeds.