Adult-onset lymphoplasmacytic orchitis in a Labrador retriever stud dog.

A formerly fertile 5-year-old 45-kg Labrador retriever was evaluated for azoospermia noted during routine semen collection for an artificial insemination. Over the past 3 years, the dog had sired 4 litters of anticipated size for the breed out of 5 breedings, the most recent a litter of 10 conceived and whelped 2 months previously. Physical examination findings were normal with the exception of bilaterally small and soft testes. An open excisional wedge biopsy of the right testis was performed under general anesthesia. Histopathology findings supported an immunologic, autoimmune pathogenesis that had resulted in infertility over the previous 4 months.