When a dog is said to go into 'heat' or is in 'estrus', it enters the reproductive cycle. This is the time that a female dog can be bred and become pregnant. Female puppies usually experience their first heat or estrus earlier than large and giant breeds. The latter might experience their first heat at 18 months to about 2 years of age, which is indeed quite long. After their first heat, dogs continue to experience heat every 6 months or so if they don't get pregnant or spayed. Larger dog breeds might only go into heat at least once a year. Dogs remain in heat for about 2-3 weeks. Some dogs might have irregular heat cycles during the first few times. Many dogs can take about 2 yeares to develop a regular heat cycle. With age, the time interval between heat cycles tends to be longer. If you don't want your pet to get pregnant, ask your veterinary clinic Ellicott City, MD about spaying, including its pros and cons.
