Estrous Cycle in Cats (Queen Cat)

The estrous cycle in cats, also known as the feline heat cycle, is a seasonal polyestrous cycle influenced by daylight length.

Queens (intact female cats) may begin cycling as early as 4 to 6 months of age, particularly during spring and summer when daylight exceeds 12 hours.

Cats are polyestrous animals, experiencing several estrous cycles during each of their two or three breeding seasons per year.

Short-haired breeds may cycle throughout the year. The use of artificial light from September to March to extend daylight hours can induce year-round cycling in females.

Phases of Estrous Cycle in Cats

There are four phases of estrous in cats namely:

1. Anestrus
2. Proestrus
3. Estrus
4. Metestrus

1. Anestrus

A female cat may initially rebuff an approaching tomcat by hissing and striking out. If she accepts the male, she flexes her spine during mounting, covers the perineum with her tail, and assumes a near-sitting position instead of displaying the typical lordosis seen during estrus.

Olfactory signals from the vulvar area may be repulsive to some tomcats, causing them to turn away after sniffing the perineum.

2. Proestrus

Proestrus is a short phase lasting one to three days. During this time, the female cat shows increased rubbing of her head and neck against objects, which may be misinterpreted by owners as increased friendliness.

This rubbing behavior becomes especially prominent around 36 hours after the onset of proestrus. It progresses to rolling—either gently or vigorously—accompanied by purring, rhythmic extension and retraction of the claws, squirming, and occasional scratching.

The female begins to vocalize with a distinct “heat cry,” a monotone howl lasting up to three minutes, which is characteristic of both proestrus and estrus. This vocalization is particularly common in Siamese cats. Additionally, the female may spray urine, and the combination of urine and sebaceous gland secretions from rubbing serves to attract nearby males.

3. Estrus

A noticeable change in behavior toward males occurs during the estrus phase. Females continue to roll and rub but no longer reject male advances. They allow mounting and adopt a crouched lordosis posture—where the thorax and abdomen touch the floor while the perineum is elevated.

This copulatory stance can also be triggered by stroking the queen’s back, thighs, or neck. The tail is displaced laterally, and a slight serosanguinous discharge may be observed from the vulva.

Lordosis is essential for successful intromission and is stimulated by the treading action of the mounting male. During copulation, the female slightly adjusts her position by alternately treading with her hind limbs.

Her facial expression becomes intense, often resembling that of an aggressive cat. Copulation typically lasts from 10 seconds to five minutes.

Post-mating behavior is characteristically dramatic:

• As the male starts to withdraw his penis following ejaculation, the female’s pupils suddenly dilate.
• As she is freed she utters a copulatory cry- a small piercing vocalization.
• She turns aggressively on the male, striking out and hissing.
• The female proceeds into the `after reaction’- violently rolls on the ground and licks her vulva.
• Mating resumes in 11 to 95 minutes.
• Mate as frequently 8 times in 20 minutes or 10 times in one hour.

Another important feature useful in the reproductive management of cats is that they are induced ovulators. An estrus female does not ovulate unless mating occurs. Ovulation can also be induced by stimulation from the male’s penile spines or by artificial means, such as using a glass rod (multiple insertions lasting about 10 seconds each, spaced 5–10 minutes apart, over a 48-hour period). Successful stimulation is typically followed by an aggressive after-reaction.

The estrus period lasts for 4–6 days, with most females becoming receptive on the 3rd and 4th day. Estrus ends abruptly within 24 hours after coitus. If pregnancy occurs, the queen will not return to estrus until the next seasonal peak or the following year. However, approximately 10% of pregnant queens may display estrus behavior between the 3rd and 6th week of gestation. Mating during this time may result in superfetation.

If a sterile mating occurs during estrus, ovulation and corpus luteum (CL) formation are induced. This resulting luteal phase is referred to as diestrus. Therefore, there are three possible patterns of the feline estrous cycle:

• Proestrus → Estrus (non-bred) → Interestrus
• Proestrus → Estrus (sterile mating) → Diestrus → Interestrus
• Proestrus → Estrus (fertile mating) → Pregnancy

If no tomcat is present, the female remains in estrus for 10–14 days and then returns to estrus again in 2–3 weeks. The average length of the estrous cycle in queens is approximately 29 days.

4. Metestrus

Metestrus is actually the interestrus period between two estrous phases when breeding does not occur.

A queen in estrus does not always mate, even when mating is desired by the owner. Several factors may prevent successful mating, such as:

• Size incompatibility: A small male may have difficulty mating with a larger female.
• Unfamiliar surroundings: A tom introduced to a new environment may be more focused on marking territory than on breeding.
• Personality: Shy or timid females may reject an aggressive male. In such cases, the owner can help by petting the queen and encouraging her to assume the mating posture. Occasionally, a queen may reject one male but accept another.