The cause of reproductive failure in the dog or bitch may be classified as infectious, hormonal, anatomic or physiological. This article* deals with infectious causes.
The most common infectious causes of reproductive failure in the bitch is a vaginitis or a low grade bacterial endometritis which affects the mucous membranes lining the uterus. In both cases the animal may be asymptomatic, and routine blood tests may be normal. Bitches and dogs that miss a breeding should have a bacterial culture done to rule out low grade infection. Organisms which have been implicated in these conditions include E. Coli, Sreptococcus, Staphyloccus, Pseudomonas, Proteus, and Brucella canis. Diagnosis requires the recovery of one or two of these organisms from a bacterial culture which should be taken while the bitch is in proestrus (this is the period where the bitch starts to show physical signs of heat such as swelling of the vulva and bleeding). Therapy can then be completed prior to estrus. The vagina always contains a low number of bacteria; this is considered normal.
Less commonly, vaginitis can be caused by Canine herpes virus which can be diagnosed but for which there is no treatment.
Brucellosis is a highly contagious venereal disease caused by the bacteria Brucella canis. This organism is shed in urine, semen, vaginal secretions and aborted fetuses. Since it can infect people, it poses a public health threat. dogs can become infected not only through breeding [the most common cause of transmission, ed.] but contact between animals at shows and performance events can also spread the disease. Brucella canis is an insidious organism that takes up residence inside cells. Because of this, antibiotics are generally ineffective and affected dogs may remain carriers for years. The consequences of Brucellosis can be devastating because infected animals can never be used for breeding and must be totally isolated from other dogs.
If a bitch or dog misses a breeding, the animal should be taken to the vet and have a bacterial culture done. As a general rule, all breeding animals should be tested for Brucellosis. A bitch should be tested within one month of breeding and an active stud dog should be tested every six months.
There are many other reasons why a bitch or dog can miss a breeding. Most of the other reasons have to do with human error. If you are really counting on a breeding and your bitch or dog has missed previously, consider having your vet perform a complete reproductive exam on your animal. for dogs, this includes evaluating the semen.
Lori Pelletier and Diane Tracy
ANTIC, June 1997
*Note: A bibliography is available from the ANTIC Editor
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