Canine Infectious Infertility

p 225-240


  • Clinical signs of vaginitis include vulvar discharge, scooting, licking, and frequent urination.
  • The cause may be bacterial, but care must be taken when trying to interpret vaginal cultures.
  • Vaginal cultures can be taken from the bitch for various reasons including pre-pubertal or post-pubertal vaginitis, post-parturient discharge, discharges during pregnancy, post-abortion discharge, and pre-breeding in normal or infertile bitches.
  • If a vaginal culture is performed because the client has noticed a 'vaginal' discharge, the potential causes and sources of the discharge should be realized. 
    • The sources of 'vaginal discharge' include anomalies of the reproductive tract, the vestibule, the clitoris, the vagina, the uterus and the perivulvar skin. 
    • Potential causes of vaginal discharge include pyometra, post-partum lochia, normal estrual discharges, vaginitis, clitoral hypertrophy, and skin fold pyoderma. 
    • A good history and vaginal examination will help rule out the potential sources of the vaginal discharge. 
  • If a culture is to be performed as part of a pre-breeding examination, then the performance and interpretation of the culture become critical. 
  • Vaginal cultures are best performed with a guarded swab to avoid contamination as the culturette is passed through the vestibule. 
  • Estrus, diestrus and anestrus cultures have yielded different results in some studies that need further interpretation.
  • Assuming the culture was taken as part of pre-breeding examination and the client needs a 'negative' culture before breeding, what kind of results can we expect on the culture? 
    • About 60% of normal bitches yielded growth from a single deep vaginal culture and 90% from a single caudal vaginal culture in one study. 
    • Another study found only 5% of bitches had no growth from vaginal cultures taken repeatedly over an 18 month period. 
    • In several studies the most commonly isolated bacteria from normal dogs were Pasteurella and Streptococci, with E. coli and Staphlocc. also being isolated, less often. 
  • Pure, single cultures of Pasteurella were most common while mixed cultures were usually Pasteurella and Streptococci or E. coli. In infertile dogs, the same basic isolates have been identified.

    Vaginal Flora from Bitches


































E. coli
























No Growth

















Fertile/Infertile (%)

  • The stage of the estrous cycle can cause the growth of vaginal flora to change. 

    • Significantly more growth was obtained at estrus than at anestrus or even postpartum in one study, although the types of organisms did not change significantly. 
    • Another study however, found no differences in the number of organisms grown during different stages of the cycle, but found that Pasteurella was isolated more during proestrus and estrus than anestrus and beta Strep. was isolated more commonly during proestrus than estrus. 
    • The E. coli population did not change during the estrous cycle. 
  • Currently, mycoplasma has caught the attention of many dog breeders. 
    • Mycoplasma has been implicated in causing cases of infertility in kennels with poor hygiene. 
    • Mycoplasmas have also been isolated from fertile as well as infertile dogs. In fact, most studies have isolated more mycoplasmas from normal dogs than infertile dogs. 
    • Mycoplasmas are fragile organisms that require special conditions and media for recovery. 
    • Vaginal cultures should be taken with a guarded swab, placed in mycoplasmal media and delivered to the laboratory within 24-48 hours of collection. Isolation will require special mycoplasma media.
  • The only bacterium known to cause infertility in the bitch is Brucella canis
    • It is not an easy organism to grow and bitches should be screened with a rapid slide agglutination test rather than relying on vaginal cultures.
  • Now that a culture has been obtained, it must be interpreted. Obviously one expects to grow something from the canine vagina. 
    • It is normally felt that pure growths of a single organism link that organism to reproductive dysfunction. 
    • However, pure cultures of Pasteurella have been isolated form normal dogs. 
    • Although no research has determined specific organisms associated with infertility, a pure growth of an opportunist organism (i.e., Pseudomonas) can make one suspicious that the organism is involved in the problem. 
    • The stage of estrus may also be considered in the type and numbers of normal bacteria. A heavier growth during estrus may be normal.
  • If a pathogen is suspected then appropriate antibiotic therapy can be instituted. 
    • Care should be taken to select a drug that is safe for pregnancy, if the treatment will continue into pregnancy. 
    • Why not just treat the animals prophylactically? 
      • Work has shown that a 10 day routine treatment with ampicillin or trimethoprim-sulfa will eradicate the flora in only one day, however overgrowths of mycoplasmas and E. coli resulted in vaginal discharges in some dogs. 
      • Also, the vaginal flora re-colonized 0-7 days in all the bitches.
  • In summary, performing vaginal cultures can lead to confusing results that need considerable interpretation. Clinical history and physical findings must be assessed along with the cultures before a final decision should be made as to the significance of the culture results.
  • Causes for vaginitis include vaginal anomalies such as intersex conditions, bands, septae, etc.; androgen therapy causing clitoral hypertrophy and irritation; vaginal neoplasia and vaginal foreign bodies.
  • Treatment

    • Treatment is often unrewarding, but may include systemic antibiotics, local vaginal infusions.
    • Recurrence is very common and these bitches may in fact have low IgA.
    • Do not breed these bitches on the next heat.
    • Vaginal ablation may be needed to treat chronic, un-resolving cases.
    Puppy vaginitis
  • Puppy vaginitis is commonly seen in pre-pubertal bitches and usually resolves at the first heat.

  • Endometritis is kind of a 'last ditch diagnosis' that you look for when everything else is normal.
  • The diagnosis is based on vaginal cultures during estrus or proestrus, which maybe give an indication of uterine organisms, however this cannot be certain.
  • If a uterine culture is desired, it is best to perform a laparotomy and take the culture directly from the uterus as the cervix of the bitch cannot normally be traversed. This may be done using TCI now. Reports vary as to the normal flora of the uterus, but it should probably be sterile. It has been suggested that deep vaginal cultures taken during proestrus or estrus can give an indication of the uterine flora, since the cervix may relax somewhat and allow a uterine discharge into the anterior vagina, or vice versa. Conclusions vary however, as to the efficacy of vaginal cultures reflecting uterine flora. One report noted a similarity between uterine and deep vaginal culture results, although no uterine pathology was evident.
  • A laparotomy and uterine culture and biopsy may be a better way to diagnose endometritis than vaginal cultures.
  • The treatment should consist of at least systemic antibiotics.
  • Newer transcervical culture techniques may become available to obtain uterine cultures.

    Herpes virus
  • Link to a paper on herpes in a bitch in Communications in Theriogenology (Volume 3 Issue 1).
  • Herpes virus is generally associated with neonatal mortality; abortion, and stillbirth
  • It has been reproduced experimentally and transmission can be vertical to the pups during pregnancy, or horizontal as the pups pass through the birth canal or from the secretions from recently infected dog.
  • If the bitch is infected in utero you may see abortion, early embryonic death and (think you have infertility).
  • The danger time is the 3 weeks prepartum to 3 weeks postpartum.
  • Viremia in pups is generally fatal. Their lower temperature allows viral reproduction. Pups may be asymptomatic because colostral antibody protects them.
  • Why the problem if the virus is short lived ? The virus becomes latent, so once the bitch is infected, it is always infected.
  • A bitch may be an unapparent carrier and stress results in shedding.
  • The antibody response is T cell response mostly and is weak, and short lived. It subsides in 60 days.
  • The diagnosis is based on culture of the aborted fetus, placenta, vaginal discharge. The titer is short lived and not very useful.
  • Vaginal vesicles are common with herpes virus, but vesicles may be present that are not herpes, so do histopath and culture on them.
  • Treatment for the pups includes increasing their temperature, possible antiviral, but the prognosis is poor.
  • Treatment for the bitch include isolating for the last 3 weeks of gestation and the first 3 weeks of lactation.
  • When breeding you can check to make sure the titer is negative (>1:2 with signs = significant The bitch may still be infected, but probably is not shedding.
  • Since the virus becomes latent, shedding can occur at any stress.
  • A vaccine is currently available in Europe.

    Mycoplasma, Ureaplasm

  • It can be cultured form normal dogs (see vaginal cultures earlier in this section).
  • Lein and Canadian workers associated them with kennel infertility and isolated the organisms from infertile dogs that were close housed, but they have not routinely been isolated from single, infertile dogs.
  • You may see abortion, early embryonic death, stillborn, infertility, and weak pups.
  • The signs vary from none, to vaginitis and balanoposthitis in males.
  • Diagnosis is based on a pure culture of the organisms from the vagina, prepuce, dead pup, placenta.
  • Treatment and prevention includes pre-breeding vaginal cultures in suspects, antibiotics (pen, erythromycin safe; tetracycline is better, but not safe during pregnancy), vaginal infusions, and cleaning up the kennel area. Individual dogs are easy to keep clean.
    Other causes
  • Adenovirus
  • Strep
  • E. coli
  • Pseudomonas

contributed by Bruce E Eilts. Modifed 16 October 2007

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contributed by Bruce E Eilts on 25 September 2012


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