Heat in cats, also known as estrus, is a period in the reproduction cycle when female cats are receptive and ready to mate. During this time, ovarian activity increases and females exhibit mating behaviors to attract potential male partners. This phase can begin as early as 4 months of age in cats, though 8-10 months is more typical for a first heat cycle.
The heat cycle itself follows a predictable progression of stages, and there are internal and external factors that can trigger its onset each season. Understanding the key triggers of feline estrus cycles allows owners to know what to expect as their cat reaches reproductive maturity.
Age
Cats typically experience their first heat cycle between 6-12 months of age (source). Some cats may go into heat as early as 4 months, while others may not have their first heat until they are 12-16 months old. According to PetMD, the average age for a cat’s first heat cycle is 6-9 months.
After a cat is spayed, they will no longer go into heat cycles. Intact female cats generally go into heat every 2-3 weeks from the spring through autumn seasons. This is because daylight length helps regulate their reproductive cycle. The frequency of heat cycles tends to decrease in the winter months when daylight hours are shorter.
Breed
Certain breeds are more likely to go into heat more frequently than others. Siamese cats, for example, tend to have more frequent heat cycles compared to other breeds. Research shows that Siamese cats on average will go into heat up to 3 times per year, while other breeds only go into heat 1-2 times a year (Source). This is likely due to genetic factors that cause Siamese cats to have higher baseline levels of reproductive hormones like estrogen.
In addition to Siamese cats, breeds like Singapuras, Bengals, and Abyssinians are also known to go into heat more often than the average cat breed. On the other hand, breeds like Ragdolls and Persians tend to have fewer heat cycles per year (Source). The frequency of heat cycles can vary quite a bit between individual cats, but some breeds are genetically prone to being in heat more often.
Day Length
The amount of daylight exposure plays an important role in triggering heat cycles in cats. Cats are “seasonally polyestrous,” meaning their heat cycles are influenced by the length of daylight hours. Longer daylight exposure can trigger estrogen production in cats, initiating a heat cycle. (Source)
In the spring and summer months when daylight hours are longer, cats may go into heat more frequently—every 2-3 weeks. But when daylight hours decrease in the fall and winter, cats are less likely to go into heat. Cats that live in tropical climates or as strictly indoor cats may cycle year-round due to consistent daylight exposure. (Source)
The key takeaway is that increased daylight triggers cats’ heat cycles. So cats exposed to longer daylight periods through the seasons, location, or living indoors are more likely to experience heat year-round or more frequently.
Presence of Male Cats
The presence of an unneutered male cat can induce or hasten heat in female cats. Male cats can detect when a female cat is in heat or on the verge of going into heat through pheromones in the female’s urine and secretion from her cheek glands [1]. Even from a distance, an intact male cat can sense these cues. Female cats do not even need to be in the direct presence of a male cat for him to trigger a heat cycle.
When an unspayed female cat is nearing her heat cycle, being around an unneutered male cat may induce a full-blown heat. The male cat’s own pheromones and behaviors in response to the female can kickstart the hormonal process that leads to ovulation and heat [2]. This is one reason that intact male and female cats should not be housed together if unwanted litters are to be avoided.
Stress
Cats can go into heat when they experience stressful events or environments. Stressful situations like moving to a new home, changes in household members or pets, or conflict with other cats can trigger a cat’s heat cycle. The stress hormone cortisol affects the hypothalamus which controls reproduction, and stress can cause the hypothalamus to initiate the hormonal cascade leading to estrus. Even subtle stressors like traveling in a car or changes in routine can induce a cat’s heat. To prevent untimely heat cycles, it’s important to minimize stressful events and changes for a cat. Maintaining stability and reducing conflict with other pets can help avoid triggering heat due to stress.
Poor Nutrition
A cat’s nutritional needs can significantly impact their reproductive cycles. Malnutrition and deficiencies in certain vitamins and nutrients may disrupt a female cat’s heat cycles.
According to the VCA Animal Hospitals, a malnourished queen, whether over- or under-weight, will suffer reproductive consequences. Good nutrition sets the stage for successful breeding and pregnancy. Deficiencies in vitamins such as vitamin A can cause irregular heat cycles.
As noted by Dibaq Pet Care, providing the right nutrition is especially important for cats in heat. A diet high in proteins and fat can help compensate for the cat’s increased metabolic needs during this time. Supplements such as vitamin E may also help regulate the heat cycle.
Overall, ensuring your cat maintains a healthy weight and gets proper nutrition, with adequate levels of vitamins and nutrients, can help encourage normal estrous cycles.
Illness
Certain illnesses may induce or disrupt a cat’s normal heat cycle. Inflammatory conditions of the reproductive tract, like pyometra, can cause persistent estrus or prolonged heat in cats. Pyometra is a bacterial infection of the uterus that typically affects older unspayed females and causes symptoms like lethargy, vomiting, excessive thirst, and vaginal discharge. The infected uterus produces excess prostaglandins and estrogen, which can prolong the signs of heat.
Other illnesses like diabetes mellitus, hyperthyroidism, and adrenal disease can also interfere with the normal cycling of hormones that regulate estrus. In addition, some medications like certain antibiotics, antifungals, and glucocorticoids can prolong or induce heat symptoms in cats. If a cat experiences unusually frequent or prolonged heat cycles, it is important to have a full veterinary workup to diagnose any underlying illness.
Spaying
Spaying a cat stops the production of hormones that trigger heat cycles. According to experts, when a female cat is spayed, the surgery removes her ovaries and uterus, eliminating her ability to go into heat (source). After spaying, a female cat will no longer experience heat cycles for the rest of her life.
While spaying is an effective way to stop heat cycles long-term, there are some risks with spaying a cat while she is in heat. Vets recommend waiting 1-2 weeks after the heat cycle finishes before spaying, as spaying during a heat cycle can lead to increased bleeding and other surgical complications (source). The best time to spay is when the cat is calm, not exhibiting behaviors associated with heat, and when surgical risks are lowest.
Overall, spaying leads to the eventual end of heat cycles for female cats. However, proper timing is important to minimize health risks to the cat.
Preventing Untimely Heat
There are several methods cat owners can try to prevent or delay an unwanted heat cycle in female cats:
- Spaying is the most effective way to prevent a cat from going into heat. Spaying refers to surgically removing the ovaries and uterus, eliminating the ability for a female cat to go into heat. Most veterinarians recommend spaying kittens around 6 months of age before their first heat cycle begins (source: https://www.wikihow.com/Calm-a-Cat-in-Heat).
- Certain supplements like melatonin and diethylstilbestrol can help suppress or delay heat cycles in cats. Ask your veterinarian about appropriate dosing and potential side effects before giving your cat any supplements (source: https://www.holistapet.com/blogs/cat-care/how-to-calm-a-feline-in-heat).
- Keep your cat indoors and away from male cats during times she is likely to go into heat. This can help delay the onset of heat cycles (source: https://www.kxan.com/reviews/br/pets-br/how-to-calm-a-cat-in-heat/).
