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Sperm Abnormalities in Dogs

Teratozoospermia in Dogs

Teratozoospermia, a condition observed in dogs, is characterized by morphological abnormalities in sperm, where 40 percent or more of the sperm exhibit irregular shapes. These abnormalities may manifest as shortened or curled tails, double heads, or improperly sized heads.

The impact of specific abnormalities on fertility remains largely uncertain. However, it’s generally understood that dogs with at least 80 percent morphologically normal spermatozoa are likely to exhibit optimal fertility. Consequently, sperm with abnormal shapes face significant challenges in fertilizing an egg.

Teratozoospermia can affect dogs of any age, although older dogs are more susceptible due to the presence of age-related diseases or conditions that can compromise overall sperm quality. While there isn’t a specific breed predisposition, Irish wolfhounds have been noted to possess notably lower semen quality compared to other breeds.


Spermatozoal abnormalities can be categorized into primary and secondary defects. Primary defects arise during spermatogenesis, the developmental stage, while secondary defects occur during the transport and storage of sperm within the epididymis, which is part of the spermatic duct system.

Typically, there are no visible symptoms associated with this disorder. The most evident indication arises in breeding dogs, where the male fails to impregnate its breeding partner.


Congenital Causes:

  • Dogs affected by fucosidosis, a metabolic disorder stemming from an enzyme deficiency called fucosidase, often exhibit abnormalities in spermatogenesis and sperm maturation. This condition leads to morphologically abnormal sperm and poor motility, particularly observed in English springer spaniels, which follow an autosomal recessive inheritance pattern with reproductive abnormalities primarily seen in males.
  • Primary ciliary dyskinesia, characterized by abnormal cilia function, results in absent or abnormal motility of ciliated cells, rendering affected animals infertile. This condition is reported across various breeds and is likely inherited in an autosomal recessive manner.
  • Idiopathic factors contributing to poor sperm morphology.
  • Testicular underdevelopment.

Acquired Causes:

  • Various conditions affecting normal testicular thermoregulation, including trauma, hematocele, hydrocele, orchitis, epididymitis, prolonged fever due to systemic infections, obesity, inability to adapt to high environmental temperatures, exercise-induced heat exhaustion, and seasonal influences, especially in summer months.
  • Infections of the reproductive tract such as prostatitis, brucellosis, orchitis, and epididymitis.
  • Drugs impacting sperm quality.
  • Testicular cancer.
  • Prolonged sexual abstinence in intact males.
  • Excessive sexual activity.
  • Testicular degeneration.


To diagnose spermatozoal abnormalities in your dog, it’s essential to provide your veterinarian with a comprehensive medical history, including any potential incidents that might have contributed to the condition, such as trauma, infections, or changes in environment, especially to hotter climates.

Your veterinarian will rely on a history of your dog’s infertility to guide the diagnostic process. This includes assessing if the dog has been unable to impregnate several reproductively-proven females despite appropriately timed mating. Additionally, the veterinarian may investigate whether spermatozoal abnormalities were detected during routine breeding soundness evaluations.

Diagnostic procedures will likely include a hormonal profile and an examination of ejaculates to assess sperm cells. Your veterinarian will also screen for bacterial infections and may employ visual diagnostic tools to inspect the reproductive tract. An ultrasound examination may reveal potential issues such as blockages, orchitis, hydrocele, hemorrhage, epididymal cysts, or tumors in the testicular region that could affect sperm ducts and morphology.


There isn’t a specific treatment for spermatozoal abnormalities in dogs; however, addressing the underlying disease or condition is paramount. Treatment approaches may vary:

  • Antibiotics and anti-inflammatory medications are typically prescribed to address infectious diseases and inflammation-induced swelling.
  • Surgical removal may be necessary for unilateral testicular tumors or severe cases of orchitis.
  • Sexual rest may be advised for conditions like edema or trauma-associated cysts.
  • In cases of idiopathic teratozoospermia, frequent semen collection might temporarily enhance sperm quality. However, the quality of sperm must be assessed before use in breeding to prevent genetic abnormalities arising from poor sperm.
  • For dogs exposed to hot environments or during the summer season, protecting them from high ambient temperatures is crucial. This may involve relocating the dog to a cooler space and adjusting their exercise regimen to minimize heat stress, unless instructed otherwise by the veterinarian for obesity treatment.


  • Offer a climate-controlled environment, especially if your dog isn’t accustomed to high temperatures.
  • Be mindful of heat exhaustion during activities like exercise or grooming, such as in drying cages.

Living and Management

Once an underlying cause is identified and treated, your veterinarian will likely recommend performing sperm evaluations at 30 and 60 days after the condition has been resolved. It’s important to note that in cases where reversible causes are involved, a complete improvement in sperm morphology typically doesn’t occur before 60 days, which roughly aligns with a full spermatogenic cycle.

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