Getting your female pooch spayed is a major step in preventing her from ever going into heat and getting pregnant. As with most things in life, however, the results don't necessarily appear in an instant. Your pet's hormones might even linger for a little while after her surgery -- no shocker there.
When a female dog gets spayed, the veterinarian takes out her reproductive organs -- the uterus and the ovaries. This procedure makes it so that she no longer is capable of getting pregnant and bearing puppies. By getting the reproductive organs out, it also dramatically decreases her body's hormone levels. The ovaries give off estrogen, and are now no longer part of her body, hence major drops in the hormones.
Hormones Staying Around in Spayed Females
A dog's sex hormones tend to diminish quickly post-spaying. However, the hormones can take a maximum of around three weeks to calm down fully. During that time period, her scent might retain the ability to draw in male canines, so don't be surprised. This only applies, however, if a female dog was spayed while in the midst of her estrus cycle.
Male Dogs, Too
Male dogs' hormones also stay around for a while after neutering, similarly to the females. Male dogs are even capable of breeding for upwards of four to six weeks afterward, so make a point to keep your pet away from "in season" females until he's well beyond that time frame. Be intelligent and play it safe.
Spaying a dog doesn't cause all of her body's female hormones to just disappear. Their sex organs aren't the only ones responsible for making their hormones, after all. Female dogs' adrenal glands also give off estrogen, however, but nowhere near the degree of the ovaries. Since spaying doesn't involve taking out the adrenal glands, dogs' bodies continue to make estrogen.
No More Heat
Spay surgery doesn't always provide immediate effects, but the effects they do offer last for life. If a female dog is spayed, she never goes into heat or "estrus" again. The heat cycle is often all about anxious behavior, watchfulness and petulance -- all things you probably don't want to see in your adorable dog. Spayed dogs generally make much more peaceful and laid-back animals. Despite all of the change, your pet will keep her core disposition -- the dog you love.