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Understanding and Managing Strep Zooepidemicus in Dogs

Streptococcus zooepidemicus, commonly known as Strep zoo, is a bacterial infection that can significantly impact canine fertility and lead to puppy loss. This guide provides an in-depth understanding of Strep zoo, its effects on dogs, and effective management strategies to prevent infertility and embryo loss.

Recognizing the Signs of Strep Zooepidemicus

Strep zoo can present with various reproductive issues in dogs:

  • Infertility: Females may appear pregnant but either produce very small litters or none at all.

  • Embryo Loss: The bacteria can cause embryo death, leading to reabsorption of the fetus if it occurs before bone development.

  • Vaginal Discharge: Some females might exhibit minor vaginal discharge, indicating an infection.

Diagnosing Strep Zooepidemicus

Accurate diagnosis is crucial for managing Strep zoo:

  • Vaginal Culture: Perform a vaginal culture while the dog is in heat to detect the presence of bacteria.

  • PCR Test: The PCR test for Streptococcus equi subspecies zooepidemicus is a reliable method for confirming the infection.

How Strep Zooepidemicus Affects Dogs

Understanding the bacterial growth and infection process is key:

  • Bacterial Growth: Strep zoo bacteria reside in the lower reproductive tract and proliferate during heat cycles when the immune system is stressed and secretions increase.

  • Infection Pathway: The bacteria can enter the uterus along with semen during breeding, where they can become fatal to the growing embryo.

  • Timing: The bacteria are particularly dangerous when the embryo starts rapid growth, but are less active when the embryo is tiny and not yet growing.

Preventing Embryo Loss and Miscarriage

Effective management involves both preventive and reactive strategies:

  • Antibiotic Use During Breeding:

  • Long-Lasting Penicillin: Administer every third day from the onset of spotting until the female refuses the male.

  • Amoxicillin: Administer twice daily from the onset of spotting until two days after the female refuses the male.

  • Goal: Maintain low bacterial numbers when the cervix is open during breeding. The cervix closes and the mucus plug forms two days after the female refuses the male, preventing further bacterial entry.

  • Creating a Protective Environment:

  • Preventive Measures: Ensure that antibiotics are administered correctly to prevent bacteria from entering the uterus with semen.

  • Duration of Treatment: Consistent antibiotic use during two breeding cycles or for one year can help eliminate the issue in affected females.

Importance of Timing and Proper Dosing

Accurate dosing based on the dog's pre-pregnancy weight is crucial:

  • Weighing the Female: Use the pre-pregnancy weight to calculate the correct antibiotic dosage, as the gastrointestinal tract size does not change significantly during pregnancy.

  • Example Dosage: For a dog that weighed 80 pounds before pregnancy, continue to use the pre-pregnancy weight for dosing throughout treatment.

Conclusion To Strep Zooepidemicus in Dogs

Managing Strep zooepidemicus in dogs requires a proactive approach involving accurate diagnosis, effective use of antibiotics during breeding, and maintaining a protective environment for embryos. By understanding the infection pathway and implementing the right preventive measures, breeders can significantly reduce the risk of infertility and embryo loss in their dogs.

For more detailed information and high-quality products to support canine reproductive health, visit or call us at 800-658-5308. We are dedicated to helping you ensure the health and success of your breeding program through expert advice and top-quality products.

Strep Zooepidemicus in Dogs
Strep Zooepidemicus in Dogs


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