As a pet owner, you may find yourself wondering just how long are dogs in heat if you find yourself with a dog who has starting her heat cycle and is bleeding while you do your best to keep her off of the furniture. A heat cycle for your dog is going to be unique, but will fall into a rough timeframe. You can keep track of their cycle to anticipate when they will go into heat next.
How Early can Dogs Go onto Heat?
Dogs can go into heat once they reach sexual maturity, which is on average around 6-7 months of age. Depending on your dog’s breed size, they may go into heat earlier or much later than this. Small breeds can go into heat as early as 4 months old, while large and giant dogs may not have their first cycle for 18-24 months, depending on just how large they are.
Should You Spay Your Dog Before They Go into Heat?
Quite a few pet owners opt to bring their dog into the vet to be spayed around 6 months old, as they cannot be certain of when they will have their first heat cycle. Thus far, there has been no research showing spaying your dog before their first heat cycle has negative effects, although some breeds have been shown to benefit from experiencing their first cycle, like German Shepherds, Labrador Retrievers, and Golden Retrievers. Unless you’re planning on breeding your dog or allowing them to mate to have one or two litters of puppies, spaying your dog before their first cycle is the only effective deterrent against pregnancy, as dogs can become pregnant even though they may not be fully physically developed.
Heat Cycles in Dogs
A dog’s heat cycle lasts much longer than a human’s, though they occur much more infrequently, happening only once or twice a year. Most pet owners refer to their dog being in heat only when they’re bleeding, but their cycle actually starts before this and concludes once the cycle begins again, usually occurring every 6-7 months on average, although these timeframes can vary.
Phase 1: Proestrus
Proestrus is the beginning of a dog’s heat cycle. This phase usually lasts 7-10 days, but the length may vary. In this phase, your dog’s vulva will swell, and you may or may not be able to notice it. During this time, your dog will start having a vaginal discharge with blood in it, which is usually what an owner will notice about the heat cycle. The vaginal discharge may not always occur during this phase, and instead start during the second phase, roughly 1-2 weeks later. Your dog will not allow any mating to occur during this phase in the cycle, but may start marking areas by urinating in order to release pheromones for other dogs.
You can usually tell when the Proestrus phase is ending, as your dog’s vaginal discharge will become clearer and more watery.
Phase 2: Estrous
Estrous is the second phase in your dog’s heat cycle and the time in which she will allow mating to happen as they are now ovulating. This phase can be as short as 3 days or as long as 21 days, but will last 9 days on average. Your dog may start arching her back and holding her tail to the side during this time period in anticipation of mating.
Your dog can get pregnant at any time during this phase, as sperm can live for up to a week in the reproductive tract and still lead to fertilization.
Phase 3: Anestrous
Anestrous is the final phase of your dog’s heat cycle, which lasts 4-5 months on average. A full cycle is defined as the start of the Proestrous phase until the Proestrous phase starts again. During the Anestrous phase, your dog isn’t ovulating and cannot get pregnant.
How long are dogs in heat can be answered easily once you know the different phases involved in their heat cycle. On average, your dog’s cycle will be 6-7 months long, but you will only notice 2 or 3 of these weeks when your dog has a bloody vaginal discharge and is ovulating, causing them to display certain behavior in anticipation of mating.