Bacteria May Cause Infertility in Dogs and Bitches

by William Truesdale, DVM

Have you experienced poor conception rates? Early embryonal or fetal death? Abortions, stillborns, fading pups, or small litters?

A common opportunistic bacteria known as T-Strain Mycoplasma may be responsible for the above complications. Researchers have isolated mycoplasma from dogs in all phases of infection. The condition is most often seen in establishments where there is a high population of breeding animals living in close quarters, hence lending itself to propagation.

Transmission of mycoplasma is not necessarily by sexual contact. Virgin males and females have been cultured with high levels of mycoplasma. It has been established that direct contact, such as shared water buckets, exercise pens, and intense close living conditions, are perfect hosts to the propagation of mycoplasma. In some affected kennels, several bitches or stud dogs may be involved, causing fertility rates to drop drastically. Ironically, many reproductively sound dogs and bitches can also harbor these agents.

Stud dogs and bitches that are subfertile or infertile may show no clinical manifestations of urogenital tract infections. However, the fetus(es) may become infected, perhaps fatally, during or at the time of birth.

It is clear to this veterinarian that the opportunistic nature of this bacteria leads it to be overlooked as a significant pathogen, since not all of its victims are affected. It is my opinion that when there is a history of reproductive problems in both male and female animals, the animals should be tested for mycoplasma as a possible cause.

Diagnosis of bacterial infection is made by isolating the organism. In bitches a deep vaginal culture is collected by passing a guarded culture swab into the vaginal canal during any phase of the estrus cycle. In males a culture of the prepuce or of the semen is performed. Culturing aborted fetuses or afterbirth can also be of significant diagnostic value.

When mycoplasma is isolated in high numbers, antibiotic therapy should be instituted. Treatment consists of dosing entire groups of animals with an antibiotic such as Baytril, Tetracycline, or Chloramphenicol. Therapy should be given for a minimum of 14 to 21 days. In many cases multiple treatment regimes are required. Successful therapy is greatly dependent on minimizing re-exposure to carriers. Single dog/bitch households are very easily treated, if kept free of re-exposure. Unfortunately for the active show enthusiast, many pathways to re-exposure exist, making it difficult for total and permanent eradication of the bacteria.

Much research is still needed to establish the definite role of these agents in breeding dogs. But in cases of canine infertility, looking for infection with mycoplasma and other bacteria should be a part of every diagnostic work-up.