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Understanding the heat cycle of your pet is important as a dog owner and a breeder; this way, you know when to achieve a successful mating result, especially if you are not planning to keep your pet a virgin for life. When a female dog gets in heat, it means they have entered the fertile part of their reproductive cycle.

It is during heat that the female dog is receptive to a male and gets the ability to reproduce. There are periods when your female dog has an abnormal heat period, like a silent or split heat season, or does not even come into heat at all for months. At this point, the pet's reproductive cycle may have been suppressed.

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On a normal day, a dog should go into heat within 6-8 months, and the cycle should last between three weeks, depending on the breed of the pet. The cycle of a pet may be affected by seasonal changes as well, like the weather getting colder or hotter.

The health of a dog plays a major role in why they may not be experiencing heat. A good example is a thyroid issue that causes irregular heat cycles, and in a more serious case, it could make your female pet not experience any cycle at all. The condition is called hypothyroidism, and it is a genetic condition. Dogs that are diagnosed with it are not to be bred.

Ovarian Hypoplasia is the description of an instance where the ovary does not develop properly, and there is an inability to produce sufficient estrogen for a female pet to come into heat or have a normal heat cycle. With this condition, the vulva and mammary glands will remain small and have an underdeveloped appearance.

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When a female dog is malnourished due to poor diet or a recent illness, her heat cycle may be delayed or altered. A dog that is fed low-quality food low in protein and fat can have problems with the normal heat cycle.

Dogs can also have tumors, and they can develop for different reasons. Some of these tumors may be cancerous, while others are benign. The development of tumors on the female ovaries of your pet will inhibit heat cycles. A diagnostic test will be carried out to show if the tumor present is a cancerous one or not.

If your pet is not coming into heat, then a full examination will have to be carried out on him or her, routine tests like a biochemistry panel, urinalysis, and blood count will also have to be run. If you are suspecting that your pet is experiencing silent heat cycles, a weekly vaginal cytology and progesterone measurements will help determine when exactly your dog is on heat.

The presence of ovarian hypoplasia in female dogs will show whether the reproductive organs are mature or not. It is often recommended to spray a female dog that is diagnosed with ovarian hypoplasia, and a thyroid problem can be figured out with blood testing. Serious reproductive problems like an abnormal heat cycle or lack of heat may require spaying. Bear in mind that these reproductive difficulties may be genetic and may be an indication of a female dog who will be unable to properly carry or care for her litter.

For the case of malnutrition, it is something that can be handled through the type of food provided for your pet and the timely nature of feeding them. A supplement may be required that would target the dog's reproductive system or keep their cycle regular. A consistent check with a vet will help you identify the presence of any type of underlying conditions.

#### References.

[wagwalking-heat](https://wagwalking.com/symptom/why-is-my-dog-not-coming-into-heat)

[petparentsbrand](https://petparentsbrand.com/blogs/health/heat-cycle-abnormalities-in-dogs?srsltid=AfmBOookadmkcrv8UnLDZWD2r3oRL8rtp4fadnKt63TYnThG3X-_4RN8)

[breedera-heat](https://breedera.com/why-is-my-dog-not-coming-into-heat)