The heat in the cat: from the first cycle to pregnancy


When it comes to cat heat, not everyone knows how it develops and how many stages it involves. In today’s card we will explain how to best behave during the heat of our kitten. The reproductive system of the cat is composed of: Ovary, Uterus which includes the uterine horns and uterine tubes (salpinx), body of the uterus, cervix and vulva. The complex, vulva and cervix, form the vagina.

The ovary is oval in shape, measuring 1 x 0.3 x 0.5 cm, is located caudal to the kidney and is supported by the mesovary. The Salpinge has a length of 5-6 cm, begins with a cranial course, then lateral and finally caudal, then continuing with the uterine horn. The uterus is in turn made up of: The uterine horns of about 10 cm in length; The uterine body about 2cm, wall + thick; from the cervix forming part of the cervix with a thickened wall, about 4.0-4.5 cm from the vulva which forms an obtuse angle with the vagina.

The Vagina that goes from the cervix to the hymen region and has a length of about 2.5 cm with the presence of a median dorsal fold. The uro-genital sinus is a non-distensible structure of about 1-2 cm, if stimulated, the animal produces vocalizations (similar to mating). Clitoris which corresponds to the penis of the male and is located on the floor of the clitoral fossa. Vulva located ventral to the anus.


What are the various periods of a cat’s heat?

The stage prior to sexual maturity is puberty. The age ranges from 4 to 18 months with an average of 9-10 months. It varies according to the type of cat:

  • free crossing to roam 7 months
  • Oriental shorthair cat 5 months
  • Oriental longhair cat 1 year

The phases of the heat of the cat are 5: Proestro, Estro, Interestro, Diestro, Anaestro.

Proestrus is present only in a few subjects (16%). It involves rubbing of the head and neck but lack of readiness to mate. Increased blood estrogen. Estro indicates readiness to mate with a Peak of follicular and estrogenic activity and the Duration ranges from 2 to 19 days and is not affected by ovulation. The frequency of oestrus cycles is reduced in long-haired and British short-haired cats.

Interestrus has a low level of estrogen with no signs or sexual receptivity and lasts 2 to 3 weeks (8-10 days). Diestro has a progestogenic dominance phase with a duration of about 40 days in pseudo-pregnant cats ( no luteolytic signal). It lasts about 65 days in gestating cats and then returns to oestrus 7-10 days after luteolysis (rupture of the corpus luteum). Anaestro is the period without sexual activity with baseline levels of estradiol and progesterone.

How to behave during the heat of our cat

The cat undergoes changes when it is in estrus (cat available for mating).
During the follicular phase there is:

  1. An increase in the depth of the fornix
  2. Decreased vaginal height at the level of the cervix
  3. Decreased cervico-vaginal angle
  4. Increase in the dorsal median fold

The cat is a species with INDUCED OVULATION, this means that only after mating does ovulation occur with a consequent peak of the LH hormone (luteinizing hormone that regulates the gonads).

  • cats that have ovulated but are not pregnant (pseudo-pregnancy) return to oestrus on average within 45 days
  • cats that have not ovulated return to heat within 16-21 days
  • cats that have ovulated and become pregnant return to heat on average within 100 days (depending on the length of lactation).

Our cat becomes pregnant during the heat period: here’s what to do.

Pregnancy: The pregnancy in the cat lasts two months and is divided into several phases. The first phase, usually lasting two weeks, is similar to that of the woman. The cat may also experience nausea and regurgitation. A sign of an ongoing pregnancy could be lack of appetite. Around mid-pregnancy, the cat begins to show a bigger and bigger belly. To the touch, you will be able to feel the kittens moving enough to assume a number.

The cat begins the terminal phase one week before giving birth, with very evident signs. The nipples become enlarged, there may be small losses of milk and the animal will prefer to doze all day. It is the right time to build a small nest, a kennel away from prying eyes that the animal will choose. Childbirth: In addition to moaning meows, the animal will lick its genitals and lose body fluids. If it is the first pregnancy, the feline may also be very anxious, thus making the operation more complicated. From the onset of labor, about an hour passes before the birth of the babies at a distance of about ten minutes from each other. Once the last puppy is born, the mother will clean them all and she will be inclined to breastfeed.


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