How to Know When Your Dog Reach Sexual Maturity

There's a popular belief that all dogs reach sexual maturity by the time they're six months old but this is not accurate. Depending on your dog's breed and size, your dog may reach sexual maturity much later.

Most young puppies will display some sexual behavior in the whelping box. This is simply play behavior and it's quite normal. Puppies will mount each other, regardless of sex. This behavior can continue, off and on, as the puppies get older. It's one way of establishing a hierarchy within the puppy pack.

Male puppies don't start producing sperm until they are around five or six months old. At this age they become capable of siring a litter. They are technically "sexually mature" but they are not mature in any other way.

Some female puppies have their first season around six or seven months of age. This is more likely to occur in Toy and small breeds. In general, the larger the dog, the longer it takes the breed to mature. Many female dogs from large breeds may not have their first season until they are a year old or closer to 18-24 months of age.

As you can guess, female puppies are not mature enough in other ways to have puppies when they're six months old. They don't have the mental or emotional maturity to raise puppies of their own even though they can physically produce puppies. A six-month-old bitch with a litter of puppies may not be a very good mother.

Nearly all breeders recommend waiting until dogs are closer to two years old before breeding. This allows time for the dogs' bodies to fully mature and for them to be mentally and emotionally mature enough to raise puppies. It also makes them old enough to be x-rayed for hip and elbow dysplasia and other genetic health problems catalogued by the Orthopedic Foundation for Animals. Dogs need to be two-years-old in order to have OFA results submitted. Having a litter produced from two parents who have good OFA scores helps reduce possible health problems in a litter.

Some people advocate spaying and neutering all puppies by the time they are four to six months old to prevent reproduction. However, puppies who are spayed or neutered at this age will lack estrogen and testosterone in their bodies which are needed as growth hormones. If at all possible it's always best to wait to spay and neuter your pet until your puppy has reached his full growth and the growth plates have closed. This usually occurs between 14 and 18 months of age. Waiting to spay and neuter at this age will reduce the odds that your puppy will develop hip dysplasia later in life as well as some cancers.

Your puppy may display various sexual behaviors in your home, such as mounting or territorial marking, but these behaviors usually disappear after spaying and neutering. If you are keeping your dog intact there are ways to train your dog to stop these behaviors.