Dogs between the ages of 18 months to two and a half years of age are thought to be  sexually mature. (Dogs younger than this can indeed produce offspring, but when younger are not considered at their most fertile.) A dog who is perhaps going to be bred should undergo a complete health profile prior to being selected for parenthood. This is called a breeding soundness exam. A physical examination, including blood tests, urinalysis, examination of prostate, evaluation of hormones, and more, can be done by your veterinarian. Semen quality and sperm abnormality are part of this examination process and are important deciding factors when considering a dog for breeding purposes.

When canine semen is viewed under a microscope for abnormalities in shape it is medically described as sperm morphology. When verifying sperm morphology, the result is reported as percent normal. Though numbers vary, the average consideration for normal morphology is about 75%. For breeding purposes, sperm is also examined for motility (movement) and volume count.

Sperm abnormalities do not show obvious signs. When a sperm sample is being examined microscopically the following will be rated.

Sperm is broken down into three parts: the clear pre-ejaculate fluid, the white sperm rich portion, and the clear prostatic fluid which comes at the end.

Sperm abnormalities can occur for a number of reasons. Samples must be carefully obtained and manipulated so as to not influence the study results.

Your veterinarian, or a specialist recommended by her who has the knowledge of the best method for collecting sperm from your pet, will gather the specimen for careful observation under the microscope. Abnormalities in head, midpiece, and tail, ease and correct direction of movement, color, volume, and presence of cells and bacteria will be observed.

There are variables that need to be considered. The discomfort of your dog during the collection process can be detrimental to the sample quality, as can length of time between collection (some researchers suggest a one hour period between collection and then combine the two samples). Contaminated equipment and an uncooperative canine can affect the collection process as well. 

Testicular aspiration or biopsy are further tools that may be used once the diagnosis of abnormal sperm has been reached. In addition, tests to analyse the membrane surrounding the sperm cell can be done. Assessing the DNA of the sperm head and the ability to penetrate the egg are two more studies that a specialist may suggest once an abnormal sperm is recognized. The testes, prostate, penis, and scrotum will be examined too.

The veterinarian will be looking for a few specific signs of sperm abnormality.

In many cases, an abnormal sperm diagnosis can be resolved by addressing the underlying cause. For instance, if there is an infection, a bacterial invasion (Brucella canis), or other illness, antibiotic therapy may cure the problem. Hormonal issues will need to be addressed, as will exposure to toxins, and thyroid dysfunction. Other factors may require simply a rest (trauma to scrotum) or removal of the causative factor (drugs that affect sperm).

Your veterinarian will advise you on the situation and give her input as to whether your pet is suitable for breeding. There are conditions that cannot be changed, like Kartagener’s syndrome and testicular degeneration, both contributing to the reality that your dog will not become a parent.

If your canine companion receives a diagnosis of sperm abnormalities, keep in mind that this is not always a permanent situation. Your veterinarian will most likely recommend a re-test of the sperm in about 60 days. There are many simple factors that can contribute to the reading of a low sperm count, like temperature of the microscope slide or use of medication. Once the factors have changed, the sperm evaluation could improve. Of course, there are cases whereby a dog could have a congenital abnormality or a disease such as cancer which may render the sperm unsuitable for mating purposes.