Cats often have a portion of abnormal sperm in any given semen sample. Infertility may arise if the amount of abnormal sperm becomes too high. This can be a problem if the cat is to be used for breeding. Pedigree cats have more abnormal sperm presence in general than house cats. Older cats may have more trouble with sperm production than younger cats. Season also can influence the amount and quality of sperm that is produced in the testes. A veterinarian can help determine any other possible causes of abnormal sperm and provide potential cures to this problem.

Sperm are made up of a head, neck, midpiece and tail. They are produced within the testes of a cat. If any issue affects the testes or surrounding areas, sperm production can be disturbed. Anything that interferes with the creation, transport, or storage of sperm can damage or deform it. This results in sperm with bends, breaks, and duplicate or missing parts, and can decrease the total sperm count concentration. 

The only symptom of sperm abnormalities may be the inability for the male cat to procreate. However, primary issues that can create these abnormalities carry more symptoms. These may include:

Anything that increases the temperature of the testes can harm sperm production. Some cat breeds pass genetic issues that affect sperm development. All known causes are listed below.

Your veterinarian will require the cat's medical history to help confirm a diagnosis. Next, a complete physical examination will be performed, including a palpation of the testes. This can help determine if both testes have descended from the body and it can also help discover lumps or excessive heat.  

A sample of semen will be needed to complete a semen evaluation. This evaluation is done by using Diff-Quik optical staining. Once stained, sperm heads will turn blue, the midsection will be pale blue and the tails will show as blue or purple. A microscope is used to see any variation to these color combination to identify sperm abnormalities.

An ultrasound may be needed to see any lumps or blockages present. The testosterone levels of the cat will need to be checked. Urinalysis can help identify any bacteria that may be causing infection in the cat. Some underlying issues may merit the castration of the cat to save its life, at which point testicular biopsy can help make a complete diagnosis.

If an underlying issue or disease is present, it will first have to be treated to help sperm quality. Where no primary concerns exist, treatment will focus directly on creating a perfect internal environment for sperm production. 

If testosterone levels are abnormally low, or if hypothyroidism is present, hormone replacement may be a treatment option. This can help supplement the needed hormones to help with sperm production. These hormone supplements may be needed for a time, or may be required throughout the cat's life.

To treat chronic inflammation, anti-inflammatory medication may be prescribed to the cat. This can reduce inflammation which will also decrease heat, allowing proper sperm creation.

If an infection is present, antibiotics will be prescribed to rid the body of the bacteria responsible. The prescription may last anywhere from 1-4 weeks.

Immune boosting supplements can help the body fight off infection or inflammation. They can also increase energy and provide nutrients to promote good sperm production.

If the underlying condition poses a serious threat to the cat’s health, as in the case of cancer, the cat may need to be neutered. While this can restore health to the cat, it will be left permanently sterile.

If the cat has undergone surgery, monitor the incision site to ensure it stays clean. If hormones or medications are being administered, regular vet visits may be needed to check dosages and look for any adverse side effects. Regular periodic testing of sperm samples will be needed to see if the sperm abnormalities are decreasing. 

Do all that you can to remove stressors from your cat’s environment. Expose your cat to other cats as this increases sperm production. Make sure that your cat is getting lots of exercise and play as this also can help with the proper sperm formation. A high quality cat food and regular supplements will keep your cat's system as healthy as possible. Or breeding, you may need to bring the female cat to your male cat while she is in heat instead of vice versa. This also decreases stress. Many cats are able to produce offspring despite the presence of abnormal sperm.