Infertility in Male Cats
What is infertility in a male cat?
Male infertility refers to the inability of a sexually mature tom (intact or unneutered male cat) to impregnate a fertile female.
Most toms reach sexual maturity between six and twelve months of age, although this can sometimes occur as late as 18 months old. A tom cat who has been unable to sire a litter with a proven fertile female by 18 months of age may be evaluated for infertility.
What are the possible causes of infertility in male cats?
There are a number of possible causes of infertility in male cats.
Some cases of male infertility may be genetic in nature. This is frequently the case in male calico cats and male tortoiseshell cats, because the combination of black and orange markings stems from possessing an additional X chromosome. (These cats carry the chromosomes XXY instead of the normal XY that is seen in males.) Some cats may be born as pseudohermaphrodites, possessing both male and female sexual characteristics, while others have different inherited abnormalities of the reproductive tract. Any of these issues can contribute to infertility. Additionally, some Persian cats are reported to possess low sex drive, though the reason for this is not fully understood.
“An anxious tom cat, or one that has had previous negative experiences associated with breeding, may be reluctant to mate.”
Behavioral factors may also be associated with infertility in tom cats. An anxious tom cat, or one that has had previous negative experiences associated with breeding, may be reluctant to mate with a female. Additionally, attempting to breed cats in a stressful environment may be associated with lower breeding success.
Less commonly, testicular diseases may contribute to infertility. The testicles may be retained within the abdomen (cryptorchidism), abnormally small (atrophied), or affected by tumors. Any of these testicular conditions may interfere with sperm production, decreasing fertility. Additionally, a number of systemic (whole-body) infections may affect the testicles and fertility. These infections include tuberculosis, feline infectious peritonitis (FIP), feline leukemia virus (FeLV), and feline immunodeficiency virus (FIV).
Disorders of the penis may also prevent successful mating. These may be hereditary defects or caused by trauma. Commonly-observed disorders of the penis in cats include priaprism (persistent erection), paraphimosis (inability to retract the penis into the sheath), and phimosis (inability to extend the penis from the sheath). Any of these penile disorders may prevent successful breeding. In long-haired cats, entanglement of long hair can lead to problems with the penis and successful breeding; improved grooming may resolve these breeding concerns.
How will my veterinarian determine the cause of my cat's infertility?
When attempting to determine the cause of your cat’s infertility, your veterinarian will likely begin with a thorough physical examination. This allows your veterinarian to assess your cat for systemic (whole-body) diseases that may be affecting your cat's fertility. Further testing will likely be based upon physical exam findings, and may include some or all of the following:
1. Complete blood cell count and serum biochemistries. Screening bloodwork, including thyroid levels, can be used to assess your cat's overall internal health and look for possible causes of infertility. A urinalysis may also be performed, to assess for the presence of urinary tract disease.
2. Infectious disease testing. Tests to assess for viral infections such as FeLV, FIV, and FIP can aid in determining the cause of infertility.
3. Semen evaluation. If possible, your veterinarian will obtain a sample of your cat's semen for evaluation. Some tom cats can be trained to provide a sample for assessment, while others may require sample collection under anesthesia. Your veterinarian will examine the semen to ensure that the sperm are structurally normal, with normal motility (movement).
4. Testosterone testing. Circulating levels of testosterone can vary significantly in normal cats, depending on time of day and other factors. Therefore, assessing testosterone levels requires more specialized testing, such as a gonadotropin-releasing hormone (GnRH) response test or a human chorionic gonadotropin (hCG) response test. In these tests, a cat is injected with a hormone known to trigger testosterone release and testosterone levels are assessed 1-2 hours after this injection.
5. Abdominal imaging. X-rays and ultrasound may be used to evaluate internal structures, such as the testicles or prostate gland.
How will my veterinarian treat my tom cat's infertility?
The treatment of infertility, and its prognosis with treatment, depends upon the underlying cause.
“Improving sanitation, alleviating overcrowding, and taking measures to reduce stress can result in improved fertility.”
In many cases, improving sanitation, alleviating overcrowding, and taking measures to reduce stress can increase fertility. Improved grooming may also facilitate breeding in long-haired cats. In other cases, however, more targeted medical interventions may be required or an infertile male may have to be removed from the breeding pool.
Although artificial insemination is rarely performed in cats, it is possible and can be considered in some situations.
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