Infertility in cats

What is infertility and what causes it?

Infertility is the inability of an individual to reproduce, and it can occur in both males and females. There are a number of causes, which can broadly be grouped into the following categories: (1) Congenital (a physical defect that the animal is born with, that prevents it from breeding) (2) Infectious (an infection that the animal has acquired, that damages the reproductive tract) (3) Hormonal (a disease that interferes with the animal's hormones so that it cannot breed) In addition there may be disorders of behaviour, as well as just improper animal management, in which case there is no true infertility but rather a misunderstanding of animal reproduction. As with humans, animals must have reached a certain body weight before they are able to reproduce. A malnourished animal may be infertile, as may an animal that is excessively physically active, such as a racing greyhound, just as a human athlete may stop her reproductive cycles during heavy training.

When will my cat first be able to reproduce?

Queens (female cats) reach puberty at about 10 months of age, but once again this may vary.

Congenital causes of infertility:

Congenital causes of infertility include: (1) Ovarian aplasia/ hypoplasia: this is absence or failure of development of the female’s ovaries. It is very rare. A blood test performed by your veterinary surgeon will detect ovarian activity, or an operation to look for the presence of ovaries can be performed.

(2) Abnormal sexual differentiation: this is when the animals sex organs fail to develop normally. For example an animal may be born looking like a female but instead of having ovaries, it has small testicles hidden inside its abdomen. Such animals usually have abnormal sex chromosomes: real females have the sex chromosomes "XX", real males have "XY" whereas an abnormally developed animal could be "XXX" or "XXY."

(3) Penis deformity: various deformities of the male’s penis can occur leading to infertility. Also abnormal testicular development can occur.

Infectious causes of infertility:

Infectious causes of infertility include: (1) Herpes virus infection: this has been associated with abortions and stillbirths in queens. It may also be involved in the inability to conceive, but this is unclear. (2) Bacterial endometritis: this is infection of the womb lining by bacteria. Diagnosis can be made by a veterinary surgeon who will test for presence of bacteria. Treatment involves antibiotics.

(3) Cystic endometrial hyperplasia (CEH): this occurs in older females. It is not solely an infectious disease, but bacterial infection contributes to the condition. There are cysts in the lining of the womb, due to the action of sex hormones acting on the uterus, and there are also usually excessive numbers of bacteria. If untreated pyometra (a potentially fatal womb infection) can develop. Treatment involves antibiotics to kill the bacteria, and drugs to inhibit the sex hormones and delay the onset of the next oestrus until the CEH has gone. (4) Feline Parvovirus (panleukopaenia) infection: this is a virus that infects cats and can kill foetuses of pregnant queens. It also causes a fatal disease in kittens. The virus has become less prevalent since the numbers of cats being vaccinated has increased, but it is important that all cat-owners continue to vaccinate their cats and kittens to ensure that this virus is controlled.

(5) Feline infectious peritonitis (FIP) virus infection: this is a virus that infects cats with fatal consequences as well as affecting fertility before the cat ultimately dies from the infection. No vaccine is available. (6) Feline leukaemia virus (FeLV) infection: this is a virus that infects cats. Infection can be prevented by a vaccine.

Hormonal causes of infertility:

Hormonal causes of infertility include: (1) Inappropriate “photoperiod” in cats: cats are seasonal breeders meaning that they usually only breed in spring, summer and autumn, and stop breeding in winter. Their production of reproductive hormones is triggered by the longer hours of sunlight that occur in the summer months. If they are not exposed to enough light during this time then they will not produce enough hormones to reproduce successfully. Ideally there should be 12-14 hours of light per day.

(2) Hypothyroidism: this is reduced activity of the thyroid gland, a gland in the neck. This means that there is reduced production of thyroid hormone, and this can influence reproductive cycles causing infertility. The condition is extremely rare in cats.

(3) Hyperadrenocorticism ("Cushing's disease"): this is over-activity of the adrenal glands resulting in excessive production of the naturally occurring steroid cortisol. It is rare in cats. (4) Hypoadrenocorticism: this is under-activity of the adrenal glands resulting in insufficient cortisol production. The condition is rare in cats.

Disclaimer

This article is for reference only.

If your pet is showing any symptoms or distress, and you suspect your pet is ill CONTACT YOUR VET IMMEDIATELY.