Felipedia

Infertility in cats

The most common cause of infertility in dogs and cats is related to husbandry problems. Breeding with a proven fertile male must occur at the optimal time for the female. Infectious, anatomic, metabolic, and functional problems associated with infertility are seen less frequently.

In cats, infectious causes of infertility include toxoplasmosis, feline leukaemia virus infection, feline infectious peritonitis, and feline viral rhinotracheitis. These may cause abortion, neonatal death, foetal resorption, and apparent infertility.

Anatomic causes of infertility include acquired and congenital problems. Fibrosis of the oviducts or uterine horns, probably a result of inflammation after infection or trauma, leads to infertility. Diagnosis is via laparotomy with dye studies. There is no reliable treatment, although microsurgery may be attempted. Similarly, bilateral obstruction of the sperm ducts can cause azoospermia and infertility. High environmental temperature can induce either temporary or permanent azoospermia. Kennel or cattery management should allow for breeding males to remain cool during the summer. Scrotal dermatitis can have the same result. Disorders of sexual differentiation result in infertility (eg, hermaphrodite, pseudohermaphrodite).

Metabolic causes of infertility, other than in severely ill individuals, are rare. Hypothyroidism has no effect on male libido or semen quality. Hypothyroid bitches may not cycle or may have increased abortion rates.

Oestrous cycle abnormalities can cause infertility. Prolonged anestrus may be congenital or acquired. Congenital forms of anestrus may be due to lack of function of the hypothalamic-pituitary axis or ovarian dysgenesis. The diagnosis of congenital anestrus is based on the age of the animal and exclusion of all other possible causes (including chromosomal defects, endocrine disorders, and previous oophorectomy). Because cyclicity in queens is determined by photoperiod, lighting conditions should be appropriate for several months before congenital anestrus is diagnosed and exogenous hormones are administered. One reported method for oestrus induction in cats is FSH (Folligon) at 2 mg/cat, IM, sid until signs of oestrus appear (not administered for >5 days).

Acquired anestrus may result from previous oophorectomy, exogenous hormonal treatment (including glucocorticoids), profound hypothyroidism, or ovarian disease (cysts or neoplasia). Diagnosis is based on history, physical examination, biochemical evaluation, ultrasonography, and laparotomy.

Prolonged oestrus may be caused by ovarian cysts that produce oestrogens, functional ovarian tumors, or exogenous estrogens. Exogenous hormones should be discontinued. Laparotomy with histopathology is usually indicated, as medical attempts at inducing ovulation (human chorionic gonadotropin, FSH, GnRH) are usually unrewarding. Prolonged diestrus can result from luteal cysts in the ovary. Medical manipulation with prostaglandins is usually unrewarding, and ovariectomy with histopathology indicated. Testicular neoplasia, commonly producing oestrogen, usually causes infertility. Castration of the affected testis may allow the other testis to regain its ability to produce sperm, but the prognosis is guarded.