Introduction

• Fertility in the male dog is dependent on normal behavior and libido, physical ability, and adequate semen quality.
• Infertilty can result from poor breeding behavior, poor libido, musculoskeletal problems preventing breeding or poor semen quality.
• Apparent infertility can stem from problems with kennel husbandry or problems with the female mate.
• Evaluation and therapy for infertility in the male dog is therefore multifactorial.
• True infertility due to poor semen quality has a poor prognosis for resolution, but usually does not impact the dogs general health.

Pathogenesis

Etiology

• Poor libido Deficient libido in male.
• Physical inability to breed a female naturally (ie achieve a copulatory lock or tie).
• Poor semen quality.
• Normal semen evaluation with poor sperm function.

Predisposing factors

• Passive or insecure male.
• Environment at collection not conducive to normal libido (eg veterinary clinic).
• Nonreceptive female due to behavioral problems (dominant) or not in estrus (not in the receptive/fertile period of the estrous cycle).
• Mismatch of stud dog and brood bitch height or conformation (eg English Bulldog).
• Vaginal anatomic problems in the bitch (stricture).
• Phimosis.
• Bilateral cryptorchidism Testicle: cryptorchidism.
• Abnormal motility (asthenospermia), morphology (teratospermia) or sperm count (oligospermia or azoospermia).
• Lack of semen (aspermia).
• Pyospermia.
• Iatrogenic causes.
• Neoplasia (testes Testicle: neoplasia , prostate Prostate: neoplasia , urinary tract).
• Significant systemic disease.

Specific

• Normal male breeding behavior can be inhibited by prior negative experience (correction by owners, aggressive bitch) or simply inexperience.
• Semen collection Semen collection for artificial insemination Artificial insemination: non-surgical Artificial insemination: surgical requires an environment in which the dog is relaxed and not concerned about previous negative experiences (vaccination, anesthesia, etc).
• Nonreceptive female dogs can be markedly aggressive with male dogs and inhibit even later attempts at copulation when they are receptive Failure to accept male at breeding.
• Dogs and bitches need to be similarly sized and anatomically compatible for natural breedings to take place.
• Bitches with circumferential vaginal strictures usually cannot be bred naturally with a copulatory lock (tie).
• Slow sperm motility, abnormal sperm morphology, and/or low sperm counts can render dogs subfertile or infertile.
• Lack of semen may indicate a disorder of sexual differentiation Disorders of sexual development.
• Inflammatory disease of the urogenital system (cystitis Cystitis , urethritis, prostatitis Acute prostatitis , orchitis) can affect semen quality adversely.
• Brucella canis Brucella canis is the single significant venereal disease that should be screened for in every breeding dog, and ruled out in any acquired infertility case.
• Administration of drugs (cimetidine Cimetidine , ketoconazole Ketoconazole , finasteride) that impact testosterone production or metabolism, or which impact rapidly dividing cells (chemotherapeutic or immunosuppressive drugs) can affect semen quality adversely.
• Sertoli cell tumors Testicle: sertoli cell tumor , interstitial cell tumors Testicle: neoplasia , and seminomas of the testes Testicle: seminoma.
• Transitional cell tumors of the bladder, urethra and/or prostate are most common neoplasia of the urogenital tract; adenocarcinomas of same are the second most common. Transmissible venereal neoplasia is uncommon in developed countries but should be considered because of travel.
• Renal insufficiency, hepatic disease, endocrinopathies, and systemic inflammatory/infectious disease can impact fertility acutely or chronically.
• Sperm functional disorders (capacitation, membrane integrity, acrosome reaction).
• Rarely, microtubule defects render sperm cells nonmotile.

Pathophysiology

• (Orchitis and epididymitis Orchitis / epididymitis result fromBrucella canisinfection.)
• Infectious prostatitis Acute prostatitis , often accompanied by cystitis and urethritis and negatively impact semen quality.
• Systemic fever can reduce spermatogenesis.
• Hard training with prolonged periods of hyperthermia can reduce spermatogenesis.
• Focal scrotal and/or epididymal inflammation can reduce spermatogenesis.

Timecourse

• The spermatogenic cycle requires approximately 62 days. Recovery of the semen quality may require 90-365 days.
• Daily ejaculation for approximately a week will deplete sperm reserves, but a normal dog should remain fertile from his daily sperm production.

Epidemiology

• Not applicable unlessBrucella canisin a kennel population or transmissible venereal tumor in free ranging dogs.

Diagnosis

Treatment

Prevention

Outcomes