The oestrus cycle in dogs is a natural process that every female dog experiences during her lifetime. It marks the fertile period during which hormonal, physical and behavioural changes occur, such as vaginal bleeding and an increased attraction to male dogs. On average, a dog goes into heat twice a year and the cycle lasts around three weeks, although the frequency and characteristics vary by breed and individual.
This comprehensive guide covers everything you need to know about the heat cycle: from the first signs to behaviour and care during this phase. It also explains how hormonal fluctuations, such as rises in oestrogen and progesterone, affect fertility and how owners can ensure hygiene using practical aids, such as dog pants. By understanding the heat cycle, you can provide your dog with the best possible support as a responsible owner, ensuring both your dog’s well-being and safety.
What is a dog’s heat cycle?
How is a dog’s heat defined?
The heat cycle is the reproductive cycle in female dogs during which they become fertile and are ready to reproduce. This cycle is characterised by hormonal and physical changes, including vaginal discharge, swelling, and behavioural changes. The heat cycle is similar to the menstrual cycle in humans, but differs in meaning and function. In dogs, being in heat signals that they are ready for reproduction, whereas in humans, the menstrual cycle marks the absence of pregnancy.
What changes occur in a bitch’s body during the heat cycle?
During the heat cycle, there are clear physical signs. The vulva swells, and a blood-like discharge occurs. Internally, hormonal fluctuations take place, such as the production of oestrogen prior to ovulation, followed by a peak in progesterone. These changes promote the release of eggs and prepare the uterus for a potential pregnancy.
What hormonal changes occur during oestrus?
The main hormonal changes are peaks in oestrogen and progesterone. In the first phase (pro-oestrus), a rise in oestrogen stimulates the body’s preparation for ovulation. During the ovulatory phase (oestrus), oestrogen levels fall and progesterone increases, which promotes fertility. After the fertile period, progesterone continues to rise during metoestrus, even if the bitch is not pregnant, which can cause a pseudopregnancy or false pregnancy.
When does a dog come into heat?
How often does a dog come into heat each year?
Most dogs come into heat twice a year, with an interval of about six months. Small breeds may come into heat more frequently (sometimes three times a year), whilst large breeds do so less frequently, usually once every eight to twelve months.
At what age does a dog come into heat for the first time?
The first heat usually occurs as soon as a bitch reaches sexual maturity, usually between six and twelve months. In small breeds, this may be earlier, whilst large breeds often do not come into heat for the first time until around the age of 18 months.
Up to what age does a dog remain in heat?
Dogs remain in heat throughout their lives, but fertility decreases as they get older. There is no ‘menopause’ in dogs as there is in humans; older dogs can therefore still be fertile, but the risk of complications during pregnancy increases.
How do you recognise when a dog is in heat?
What are the signs of a dog being in heat?
The first symptoms of being in heat are subtle behavioural changes, such as increased affection or restlessness. Physical signs include swelling of the vulva and discharge that is initially bloody. Male dogs may also show increased interest in the female dog even before she is actually fertile.
What symptoms occur during a dog’s heat?
Bitches in heat typically experience blood loss, which becomes lighter or pinker later in the cycle. They may urinate more frequently, releasing pheromones that attract male dogs. Other symptoms include swollen teats, leading to an elevated head posture (standing with the tail held to one side when a male dog approaches).
How does a dog’s behaviour change during the heat cycle?
Behavioural changes before the heat
Before the actual fertile phase, a bitch often displays nervous, playful and overly affectionate behaviour. Males may already show interest from this stage onwards.
Behaviour during the heat
During the fertile phase (oestrus), the bitch’s behaviour becomes more provocative: she shows interest in males and may display flirtatious behaviour. She often allows mating at this stage, which is biologically driven by pheromones and hormonal changes.
Are there any behavioural changes after the heat?
After the heat, behaviour usually returns to normal. However, some dogs may develop symptoms of false pregnancy, characterised by nest-building, swollen teats and a reduced appetite.
How long does a dog’s heat last?
What is the average duration of a dog’s heat?
The total heat cycle lasts approximately three weeks, but can vary from 18 to 24 days, depending on the individual and the breed.
How long does the bleeding last during the heat cycle?
Bleeding occurs mainly during the pro-oestrus phase and lasts on average 7 to 10 days. The intensity and colour of the bleeding decrease as the fertile phase begins.
What are the different phases of the oestrus cycle?
What is pro-oestrus (the first phase)?
Pro-oestrus is the preparatory phase, during which the vulva swells and bleeding occurs. The bitch is not yet receptive to mating during this phase.
What happens during oestrus (the most fertile phase)?
Ovulation takes place during the oestrus phase, and the bitch accepts mating. Her behaviour changes significantly during this time, and male dogs are strongly attracted by her scent.
What happens during metoestrus (after the fertile period)?
During metoestrus, hormone levels return to normal, unless pregnancy has occurred. Symptoms of pseudopregnancy may develop during this phase.
What is anestrus (the resting phase)?
Anestrus is the period between two heat cycles during which the body fully rests. This phase lasts several months, depending on how often the dog comes into heat.
When is a dog fertile during the heat cycle?
How do you know when a dog is most fertile?
Dogs are most fertile during the oestrus phase, which lasts 7 to 10 days within the heat cycle. Behavioural changes such as increased flirtatious behaviour and acceptance of male dogs mark this peak.
How can you recognise ovulation in a dog?
Ovulation can be confirmed by a progesterone test at the veterinarian’s office or by subtle signs such as reduced bleeding and a clear willingness on the part of the bitch to mate.
How do you determine the optimal time for mating?
The safest and best time for mating is approximately 2–4 days after the start of the oestrus phase. Guidance from a veterinarian via hormonal tests is recommended.
How do you care for a dog in heat?
How can you keep the house clean during the heat?
Place blankets or dog-friendly mats in areas where the bitch spends a lot of time. Use washable dog pants to limit blood loss and use organic stain removers.
What is the purpose of dog pants during the heat cycle?
Dog pants help keep the house clean and prevent the bitch from coming into direct contact with surfaces. They are also useful for temporarily preventing unwanted mating.
What special care does a dog in heat need?
Bitches in heat require extra hygiene, such as regularly cleaning the area around the vulva. It is also important to reduce stress by ensuring they get plenty of rest and by keeping a close eye on them during walks to avoid contact with male dogs.
Conclusion: Awareness of the oestrus cycle in dogs
Understanding the heat cycle is essential for responsible owners. Adequate care and awareness of hormonal and behavioural changes are necessary to ensure the dog’s well-being.
Imby Petfood offers nutritional solutions and advice for optimal support of your dog during this stage of life, so that both owner and dog can get through these periods comfortably.
