| Stage of Cycle | Average Duration | Range | Comments |
| ‘Pro-oestrus’ or‘pre-season’ (before the bitch comes on heat) | 9 days | 0-17 days | In this phase male dogs will be very attracted to the bitch, but although she’ll flirt with them, she is not interested in breeding. There will be a blood-stained discharge from her vulva and her vulva will be swollen in this stage |
| ‘Oestrus’ or ‘season’ (bitch is on heat) | 9 days | 3-21 days | In this phase male dogs will be very attracted to the bitch, but although she’ll flirt with them, she is not interested in breeding. There will be a blood-stained discharge from her vulva and her vulva will be swollen in this stage |
| ‘Metoestrus’ or ‘post-season’ | 90 days | variable | Metoestrus occurs in bitches that have not been mated during their season, or in bitches where the mating has not been successful. In this stage, bitches still have hormones in their blood that are similar to those they would have if they were pregnant. Sometimes these hormones cause the bitch to display signs that she is pregnant. This is known as a ‘phantom pregnancy’ or ‘false pregnancy’ and can include signs such as enlarged mammaries (teats), and a milky coloured discharge from the teats |
| ‘Anoestrus’ or ‘no season’ | 75 days | 5-10 monthsMuch breed variability | Anoestrus is the period of complete sexual inactivity between cycles. During this stage the bitch will not be interested in male dogs at all |
| Average Duration | Range | Comments |
| Age at first season(reaches puberty) | 8 months | 6-24 months | This can vary according to the breed of your dog. Larger breeds tend to be older at their first season as they do not finish growing until later in life. It can also be delayed by poor nutrition |
| ‘Pro-oestrus’ or‘pre-season’ (before the bitch comes on heat) | 9 days | 0-17 days | In this phase male dogs will be very attracted to the bitch, but although she’ll flirt with them, she is not interested in breeding. There will be a blood-stained discharge from her vulva and her vulva will be swollen in this stage |
| ‘Oestrus’ or ‘season’ (bitch is on heat) | 9 days | 3-21 days | In this stage, the vaginal discharge will change to a straw-coloured (clear with a slight yellow tint). Male dogs will be very attracted to the bitch and she will stand to allow mating. |
Ovulation occurs
(when the eggs are released from the ovaries) | 2 days after ‘on heat’ hormones are released | From the last day of pre-season until 7 days into the season | After the eggs are released from the ovaries they take 48 hours to mature to the point that they are ready to be fertilized by the sperm. Sometimes the bitch will have already mated, and the sperm will be ready and waiting, when the eggs mature (48 hours after ovulation) to be fertilized |
| Best time to breed | 3 to 6 days after ‘on heat’ hormones are released | From the last day of pre-season until 7 days into the season | After the eggs are released from the ovaries they take 48 hours to mature to the point that they are ready to be fertilized by the sperm. Sometimes the bitch will have already mated, and the sperm will be ready and waiting, when the eggs mature (48 hours after ovulation) to be fertilized |
| Length of Pregnancy | 64 days after fertilization of eggs | 57-68 days | Note: the eggs must be matured (48 hours after ovulation) in order to be fertilized. Therefore the date of mating is not always the same as the date of fertilization!! |
| Time until next season after having puppies (whelping)“Anoestrus” | 7 months | 4-12 months | If your bitch has a very short interval before her next season, it is not a good idea to breed her again, as her uterus (womb) will not have had time to heal. I usually suggest having at least one season between matings to let her body fully recover. Pregnancy usually increases the phase of Anoestrus by 28 days on average |
| Lifespan of Sperm | 4 days | 1-7 days | It is possible for more that one dog to mate with a bitch during her season. A dog’s sperm can last for up to 1 week, so it is very possible to have more than one father of pups in the same litter. I have seen this happen many times, so make sure you keep your bitch away from any dogs that you don’t want her breeding with! |
