Breeding in cats

'One of the most striking differences between a cat and a lie is that a cat has only nine lives.'

Mark Twain

The normal length of pregnancy in cats is 58-65 days (approximately nine weeks). Cats normally give birth to between one and four kittens. Female cats usually reach puberty between four and seven months of age, although some breed such as Persians, Siamese and Birmans can have their first 'heat' at 18 months of age.

Mating usually occurs when the cat is 'on heat' which occurs three to four times during the mating season and lasts 14-21 days. The mating season in cats is usually twice yearly in spring and autumn. A cat on heat normally is very vocal, and flicks its tail frequently and will often back up to the owner and show signs of excessive affection.

The best time for mating a female cat is usually after the second day of being 'on heat'.. After having kittens, a female cat will usually come back into heat 4-6 weeks later. Cats normally 'ovulate' only after sex and if they do not fall pregnant during the mating, will normally come back into heat a month later.

During pregnancy, the unborn kitten is susceptible to any drugs which the Queen is given, such as antibiotics, worm tablets and flea-control agents. It is advisable not to treat the Queen with any drugs, especially during the first four weeks of pregnancy. Often breeders will medicate the Queen

Cats on heat

When a cat is on heat, its personality changes considerable. They usually become very vocal, roll around on their backs and arch their backs towards objects and people. They normally stay on heat for up to 3 weeks, unless they are mated. It is best not to breed a female cat on its first heat, although in the wild this normally occurs. Delaying mating until the second heat usually reduces the complications during the birth process as the female cat is physically larger and her pelvis wider. So for the first heat, many breeders use medications to postpone the heat season.

If your cat is on heat, you have five options:

1) Mate her with a tomcat - only advisable if you are intending to become a cat breeder as costs and time are prohibitive.

2) Have her desexed - this is the recommended method. Cats can safely be desexed when on heat, although vets normally charge a surcharge because of the time involved in the procedure

3) Postpone the heat by medication - drugs such as Polaramine® or Periactin® (a blood pressure tablet). Polaramine is an antihistamine which is available over the counter at chemists and given at a dose of 1 mg per day (1/2 tablet). The antihistamine works by tranquillising the cat and making her forget that she is on heat. Periactin is available only on prescription from your vet and at a dose of ½ tablet daily has the effect of reducing the cat's blood pressure and thereby having a tranquillising effect similar to Polaramine. The effect of both drugs lasts for about 24 hours. Another drug which is frequently used in Ovarid® which is a progesterone-like drug that tricks the cat's brain into thinking the cat is pregnant. The drug postpones the heat for three months. The only side effects with Ovarid is an increased chance of getting an infection in the uterus (metritis or pyometra) and high blood sugar. Cats that are regularly given Ovarid three or four heats in a row have a 50% chance of having pyometra, so this drug should be used only once or at most twice. Ovarid is also a strong appetite stimulant, so don't be surprised to see your cat eating five times a day while on this drug.

4) The cat can be taken off heat by inserting a cotton ear swab into the vagina. The friction which is caused by inserting the swab will cause the cat to ovulate and therefore go off heat. She will however come back on heat in 3-4 weeks time.

5) Do nothing - the cat will stay on heat for three weeks and drive everyone mad. Boarding the cat during this time may be worth considering if you're threatened with divorce.

Queening (giving birth)

Pregnancy normally lasts for seven weeks (average 63 days; normally between 58-65 days) although some cats can have kittens a week early or later. It is also normal for a cat to give birth to a kitten or two, then have a delay of up to 24 hours before giving birth to another kitten or two. In some cases this can be put down to serial matings with the tom cat where they mate progressively over a couple of days, but in a lot of cases it is assumed that the delay is due to a delay in the birth hormones released by the brain. If a cat goes into labour and no kittens appear within two hours, there is reason enough to have her checked by your veterinarian. If her cervix is dilated, the vet will give her an Oxytocin® injection which will force the uterus to contract and quicken the labour. Many breeders have this injection in stock for emergency use.

Fig. 1. Pregnancy diagnosed using Xray

After the queen has given birth, also check her mammary glands on a daily basis. Infections of the glands (called mastitis) is a common problem and needs to be treated by your vet.

Milk fever is not a common problem in cats compared to dogs, but it is always best to ensure that the queen is getting an extra calcium supplement after she has the kittens (and not during pregnancy as this makes them more prone to milk fever). The best calcium supplement for cats is in liquid form, such as Calcium Sandoz®, which is given at 1-2 mL daily by mouth). These are absorbed more rapidly and more palatable than powders.