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Sperm Abnormalities in Cats

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Spermatozoal Abnormalities in Cats


Teratozoospermia is the diagnosis given when spermatozoal (sperm cell) abnormalities are present in 40 percent of the ejaculate. That is, the sperm cells may have short or curled tails, double heads, or head that are too large, too small, or badly shaped. The effect of specific abnormalities on fertility is largely unknown, but optimal fertility is expected in cats that have at least 80 percent morphologically normal spermatozoa.

This condition can affect cats of any age, but older cats are more likely to have other age-related diseases or conditions that affect overall sperm quality. There is no breed predilection.




Spermatozoal abnormalities are sometimes classified into primary and secondary defects. Primary defects occur during spermatogenesis, the development stage, and secondary defects occur during transport and storage within the epididymis (part of the spermatic duct system). Often there are no outward symptoms of this disorder. The most obvious symptom makes itself apparent in the breeding cat, when the male cat fails to impregnate a breeding partner.





  • Primary ciliary (hair-like cells) dyskinesia (difficulty in performing voluntary movements) – an abnormality of the cilia which results in absent or abnormal motility of the ciliated cells; affected animals are infertile; reported in many breeds; probably autosomal recessive inheritance
  • Idiopathic (cause unknown) inherent poor sperm morphology
  • Testicular underdevelopment – tortoiseshell or calico tom cats
  • Excessive inbreeding – inbreeding in domestic cats can result in a significant reduction in the percentage of normal cells within one generation; wild species with loss of genetic diversity experience an increase in teratozoospermia and a reduction in fertility



  • Conditions disrupting normal testicular thermoregulation (temperature regulation) – trauma; hematocele (swelling due to a flow of blood); hydrocele (collection of fluid in a sac); orchitis (inflammation of the testis); epididymitis (inflammation of the epididymus, the ducts through which the sperm are conveyed); prolonged fever secondary to systemic infections; obesity (increased scrotal fat); inability to adapted to high environmental temperatures; exercise-induced heat exhaustion; seasonal (summer months)
  • Infections of the reproductive tract – prostatitis; brucellosis (infectious diseases caused by the bacteria Brucella melitensis); orchitis (inflammation of the testis); epididymitis (inflammation of the epididymus, the ducts through which the sperm are conveyed)
  • Drugs
  • Testicular cancer
  • Prolonged sexual abstinence in a non-neutered male
  • Excessive sexual activity
  • Testicular degeneration





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