Abstract: A routine andrology and semen examination was carried out on a group of 12, one-year old, Pelibuey breed rams, but one individual had persisting leukocytospermia. No clinical alterations of the reproductive system were found in any of the rams. At slaughter of the problem animal, the seminal vesicles were found to be markedly lobulated and larger than normal, as were the vas deferens ampoules. When dissected, both structures contained creamy white yellowish material. Histopathology demonstrated ampullitis and seminal vesiculitis. A Gram-negative pleomorphic bacillus was isolated from both of the organs, which was characterized through the API 20E system and PCR. It was found to behave similar to the reference strain for Actinobacillus seminis ATCC 15768.