When does a female dog have her first estrus cycle? A bitch's first estrus cycle, also known as the onset of puberty, generally occurs between six to twelve months of age, but it can vary based on factors like breed and size. Smaller breeds may experience their first heat cycle earlier than larger breeds. Some giant breeds might not have their first heat until they are 18 to 24 months old.
What are the signs of estrus?
Signs that a female dog is experiencing an estrus cycle often include:
Swelling of the Vulva: This is one of the earliest signs. The vulva becomes more prominent and may appear slightly swollen.
Bloody Discharge: A bloody vaginal discharge typically accompanies the initial stage of proestrus.
Behavioral Changes: Restlessness, increased affection, and a heightened interest in male dogs are common behavioral changes.
The earliest indicator of estrus is swelling or engorgement of the external vulva, but this swelling is not always obvious. In many cases, a bloody vaginal discharge will be the first thing that an owner will observe when their bitch comes into heat. In some cases, the discharge will not be apparent until several days after estrus has begun. The amount of discharge varies with the individual dog; some dogs have only a tiny amount of discharge while others bleed more. Occasionally the discharge will not be apparent at all and this is referred to as a ‘silent heat’.
The vaginal discharge will change in color and appearance as the cycle progresses. At first, the discharge is darker in color, but as the days pass, it changes to a watery, pinkish-red discharge, usually about 10-13 days into the cycle. A female dog that is in heat will often urinate more frequently than normal, or may develop 'marking behavior', in which she urinates small amounts on various objects when she is on a walk. During the estrus or heat stage of her estrus cycle, her urine contains pheromones and hormones, both of which signal her reproductive state to other dogs. This is the reason that dogs in heat can attract other dogs, particularly males.
If the bitch discharges anything other than blood and in any other color other than maroon, red, or pink, or it has a strong odor, then please contact your breeder or a veterinarian.
What are the stages of a bitch’s reproductive cycle? The estrus cycle consists of four distinct stages. What breeders often refer to as “coming into heat” or “coming into season” refers to the stages of proestrus and estrus:
How often does a female dog come into heat?
Most bitches come into heat twice per year, or about every six months, although the interval can vary between breeds and from dog to dog. Small breed dogs may cycle three times per year, while giant breed dogs may only cycle once every 12-18 months. When young bitches first begin to cycle, it is normal for their cycles to be somewhat irregular. It can take up to 2 years for a female dog to develop regular cycles. There is no season of the year which corresponds to a breeding season for domesticated dogs.
How long does estrus last? Although this can vary with the individual dog, on average a dog will be in heat for 3 weeks. Estrus ends when the discharge completely disappears and the vulva returns to its normal size. It is important to note that even if your bitch has stopped bleeding she may still be fertile so if you are not intending to breed her do not let her run loose with intact males until a few weeks after you notice her bleeding has completely stopped.
At what stage of the estrus cycle is the dog able to get pregnant? The female dog usually ovulates at about the time that the vaginal discharge becomes watery; this marks her most fertile stage and at this time she will usually become receptive to breeding. However, sperm can survive for a week in the reproductive tract and still be capable of fertilizing the eggs, so it is possible that she can get pregnant at any point while she is in estrus. Contrary to popular belief, it is not necessary for the female to 'tie' with the male dog in order to get pregnant. With Bull Terriers their fertility period is often later in their season –usually during the third week (day 15-21).
How long does pregnancy last in a dog and when can pregnancy be detected? Pregnancy lasts approximately 9 weeks (63 days) in dogs. Generally it is not possible to detect pregnancy during the first 3 weeks. An experienced veterinarian may be able to palpate or feel the fetuses in the uterus of a relaxed dog at about 28-32 days of pregnancy. Ultrasonic pregnancy diagnosis can be performed successfully any time after 25 days of pregnancy. At 6 weeks of pregnancy, the fetal skeletons begin to become calcified and pregnancy can be confirmed by means of x-ray after this time.
How can I prevent my dog from becoming pregnant? The best way to prevent your dog from becoming pregnant is to have an ovariohysterectomy or 'spay' operation. OR to keep her separated from intact males, even for a week or so after any visible signs of her season have passed.
Is there anything I can do if my dog has been mismated, or accidentally mates with another dog? If this happens, you need to contact your veterinarian as soon as possible. There are mismating injections that can be used within the first 1-2 days after mating occurs, but there are risks associated with their use. Your veterinarian will discuss your options and any risks associated with them.
