How Often Do Cats Go Into Heat?

Unlike dogs, female cats do not cycle at regular intervals throughout the year. Cats tend to come into heat in relation to the season. The mating season in cats is determined by a number of factors, including the length of daylight and the presence of other cats. When there are 10 hours of daylight and other conditions are optimal, the hormonal system is activated, and the queen begins the reproductive cycle. The natural mating season of cats in the Northern Hemisphere is from March to September. Long-haired cats are more sensitive to light and temperature than short-haired breeds. Cats under artificial lighting may come in heat anytime of the year, while house cats under intermittent light have unpredictable heat cycles.

When Do Cats Go Into Heat?

Throughout the cat breeding season, queens go into and out of heat several times but not always at regular intervals. They may exhibit continuous heat cycles in early spring (averaging 14 to 21 days from the beginning of one cycle to the beginning of the next), followed in late spring by cycles that are further apart. Each queen establishes her own normal rhythm.

Puberty in Cats

Most female cats reach puberty and have their first heat cycle between five and nine months of age, occasionally earlier. Yet we do not want her to become pregnant until the queen is physically and mentally ready. Persians as a breed are considered late matures and may not reach puberty until one and a half years of age.

Cat Heat Cycle

The estrous heat cycle or reproductive cycle of cats has four distinct stages: anestrous, proestrus, estrus and metestrus.

Anestrous in Cats

• Is where the queen does not come into heat and her ovaries are in a quiescent (inactive) stage. This would be the period of no sexual activity. In most areas of the United States, this would run from late September through mid-January. The low light and short length of daylight is a primary factor in suppressing the heat cycles during the winter months. Cats kept indoors may be stimulated to cycle from artificial light sources that are lengthening the queen’s day. If light levels are similar to those experienced during the peak breeding seasons of early spring, they start cycling.

Proestrus in Cats

• Is used to describe the stage of estrous immediately following anestrus. In this stage of heat, the ovaries are becoming active in follicle formation. This lasts from one to four days. Unlike the bitch, the queen’s vulva enlarges only slightly and appears somewhat moist, but no discharge comes from the hormonal changes. The queen shows increased appetite and restlessness, utters short low calls, and displays more than usual affection for her owner. This is best described as the period in which the cat is coming into heat, but is not yet ready to be bred. Hormones such as the follicle stimulating hormone (FSH) and estrogen help promote the egg development occurring during this phase.

Estrus in Cats

• Is the period of the heat cycle when the cat is able to become pregnant. Estrus in cats is what breeders refer to as heat or the call, as queens can be quite vocal, yowling when in heat. Length is variable but usually lasts 10 to 14 days. During this period, the queen will insist the owner notice behavioral and other physical changes in the female. The queen “in heat” will vocalize and urinate frequently. She will appear overly passionate by rolling, rubbing and assuming the breeding posture with the head and forelegs low to the ground and the rump area held high. As the urge to mate becomes pronounced, her cries become alarming – sounding like those of an animal in pain. This “call” will attract toms from near and far. Unlike the female dog, the queen usually has little if any noticeable vaginal discharge in either the proestrus or estrus phase.

Metestrus in Cats

• Is the time immediately after estrus. The female will not pay attention or accept the male at this time and will return to her normal self.

The actual breeding or copulation takes place during the estrus phase. Copulation usually lasts 10 seconds or less, but although the time is short, most females will breed repeatedly over a 24 to 48 hour period, helping to ensure semen from the male is present and the queen’s eggs are ovulated. Queens are “induced ovulators,” meaning the act of breeding stimulates the female to release (ovulate) her eggs. Repeated breeding ensures ovulation with copulation happens as many as 36 times in 36 hours. In other mammals (dogs, cattle and humans), ovulation occurs even if breeding does not. A cat not bred will not ovulate, but will usually go out of heat within 10 to 14 days. Female dogs will be in anestrous for four and a half months, but the queen not induced to ovulate by breeding will come into heat every two to three weeks (or sooner) until breeding and ovulation occurs.

Cat Breeding Problems

Good husbandry of the cattery is key to a robust breeding program. Queens that are underweight, or overweight may have difficulties conceiving. Appropriate light, temperature and contagious disease control can have a marked effect on estrus cycles. Vitamin and mineral deficiencies, especially copper and taurine, can lead interrupted estrus cycles. Overcrowding or inter-cat aggression with other cats can cause stress that can lead infrequent estrus cycles. Even the stress of traveling and showing can cause disruptions.

Queens can also have some unique situations regarding reproductive problems. The most common issue is known as a “silent heat”. This occurs when the queen is in estrus but does not outwardly display with calling and other “in heat” behaviors or symptoms. This most commonly occurs in maiden queens, or queens that are timid or lack confidence, but it can occur in any queen at any age. The lack of outward signs of estrus will not indicate to the male that the queen is receptive, and thus no copulation will occur. Occasionally, a seasoned male may detect a queen in silent heat and breed her, but only if he has access.

Queens can also have problems with conceiving due to cases of cystic ovaries, endometrial hyperplasia, and even some bacterial infections. Cystic ovaries can be difficult to treat. Some exogenous hormones can be used to treat cystic ovaries or help induce estrus, but must be used very carefully under the direction of a veterinarian. Uterine infections of Streptococcus g and E. coli species of bacteria have been linked to infertility, low kitten numbers and even neonatal death (Fading Kitten Syndrome). Maiden queens seem to be at most risk for this issue, but it can occur in experienced queens. Treating with antibiotics (under the guide of a veterinarian) can help lessen these issues in some queens. Unlike dogs, artificial insemination is not used widely in cat breeding due to the fact that copulation needs to happen in order to induce ovulation.

How to Stop a Cats Heat Cycle

There are occasions when a breeder does not want a queen to be cycling. Some queens cycle frequently with little break in between. This can potentially lead to infection in the uterus, called pyometra, which can lead to infertility and even death of the queen. Also if a female is doing well on the show circuit, a breeder may want to keep her from cycling in order to finish a show season or title. Queens can be “knocked” out of heat by vaginal stimulation. This must be done very carefully as not damage the vagina. A clean rectal thermometer can be lightly inserted into the vagina to induce ovulation. There is an acupressure point midway between the rectum and the vaginal (known as CV-1) can be stimulated to induce ovulation and end an estrus cycle. Melatonin can also be used to reduce cycling in cats, although not all queens respond to melatonin supplementation. There is also a feline “birth control” implant called Superlorin that can be implanted to keep a queen in anestrus until it is removed.

Updated by Amy Hanson, DVM. Amy Hanson, Doctor of Veterinary Medicine, is an associate veterinarian at the Cat Clinic of Lawrence in Lawrence, Kansas. She is a 2010 graduate of Kansas State University College of Veterinary Medicine. Her special interests include felines, acupuncture and dentistry. Her hobbies include showing cats and she is a judge for the American Cat Fanciers Association (ACFA).