Semen Culture & Canine Fertility
December 05, 2024
Guest blog by Dr Emmanuel Fontaine, Scientific Communications Veterinarian at Royal Canin North America
Recently, I came across an intriguing research article focusing on the microbiome present in the semen of male dogs. The term 'microbiome' refers to a community of microorganisms (bacteria, fungi, viruses, etc.) living in a specific environment, and it has been a central theme in my presentations recently, where I've highlighted the crucial role of the gut microbiome in kittens and puppies. However, this was the first time I encountered its study in the context of male canine reproductive health. The potential revelations hidden within the microbial communities of dog semen could open a new frontier regarding male dog infertility. In this blog, I share with you what I found in this paper and how I think it can help us when it comes to dog breeding.
In the field of canine fertility testing, we often find ourselves navigating between traditional methods and innovative techniques.
A commonly practiced traditional method involves analyzing the ejaculate (performing what we call a 'spermogram') to detect abnormalities in semen quality. Some discussions also revolve around performing bacterial cultures of the semen, especially when a bacterial infection is suspected.
I must admit I have always been skeptical of this approach, given the inherent non-sterility of semen.
It's common to find some bacteria in semen, making the interpretation of such tests quite complex.
My skepticism was partly what made the study I mentioned earlier so intriguing; it offered a fresh perspective on how semen quality correlates with the bacterial populations in a male dog's ejaculate. And the research provided several insightful findings that warrant attention for those of us interested in male dog fertility I believe.
Rethinking Bacterial Cultures in Male Dog Semen
In male dogs, the ejaculate is divided into three distinct phases, each with its unique characteristics.
The first phase, known as the pre-sperm or urethral wash, primarily consists of a clear fluid that serves to cleanse the urethra. The second phase is the sperm-rich fraction, which is the most critical for reproductive purposes as it contains the majority of the sperm. Lastly, the third phase is the prostatic fluid, a larger volume that follows the sperm-rich fraction and helps to flush the sperm into the female's reproductive tract, providing a medium for the sperm to swim in.
The study challenged the idea that it's essential to differentiate between culturing the second (spermatic) and third (prostatic) parts of the ejaculate.
It found that both sections produce similar outcomes, greatly simplifying the collection process, especially given the larger volume of the prostatic phase.
This could make the analysis process smoother, more accessible, and less daunting.
Secondly, they found that bacterial communities in semen are consistent between dogs with normal sperm (normospermic) and those with a high number of abnormal sperm (teratozoospermic)… which was quite unexpected.
Although this is a preliminary study and the usual disclaimer of 'needing further research' applies, it suggests we should be cautious about hastily conducting bacterial analyses on male dog ejaculate.
I frequently emphasize that the value of a test lies in its interpretation, and this study underscores a crucial point: solely observing infertility in a male dog makes deciphering the results of a semen bacterial culture exceedingly challenging.
Mycoplasma in Male Dogs: A Bacterial Conundrum?
In the discussion section of the paper, there was a detailed paragraph on Mycoplasma in canine semen and its implications.
Mycoplasma, a bacterium commonly found in the genital tracts of various species, including dogs, continues to be a subject of debate regarding its impact on both male and female fertility.
The study highlighted that a significant majority (89%) of male dogs naturally carry Mycoplasma within their reproductive systems.
This prevalence complicates the interpretation of qualitative PCR tests used to detect Mycoplasma in ejaculate; its commonality raises questions about the meaning of positive findings.
Again, the value of a test lies in its interpretation, which, in this case, appears to be particularly complex given our current knowledge.
Currently, there is no quantitative benchmark to distinguish between normal and elevated levels of Mycoplasma in dog semen, leaving its role in male infertility ambiguous at best. Often considered a secondary pathogen, Mycoplasma flourishes under conditions established by primary issues.
Importantly, this insight suggests caution in prescribing broad-spectrum antibiotherapy, which could lead to antibiotic resistance and disrupt critical microbiomes—vital for animal health.
The prospect of integrating cutting-edge tests like semen microbiome analysis into our practice is thrilling. These advancements promise to unlock new dimensions in canine fertility, marking the dawn of a transformative era in reproductive veterinary medicine. Indeed, we are on the cusp of significant breakthroughs, with a palpable sense of change sweeping through our field.
The opinions expressed by authors on the Canadian Kennel Club Blog and those providing comments are theirs alone, and do not reflect the opinions of the Canadian Kennel Club or any of its employees.
Les opinions et les commentaires exprimés dans le blogue du Club Canin Canadien sont ceux des auteurs et ils ne reflètent pas les opinions du Club Canin Canadien ni de ses employés.
Emmanuel Fontaine
Emmanuel Fontaine graduated from the Toulouse Veterinary School in 2004, he continued his studies at the Alfort Veterinary School (Paris) as trainee Vet in the domestic carnivore unit of the Reproduction Department. From 2005 to 2011, he worked at the Centre d’Étude en Reproduction des Carnivores (CERCA) [Research Centre for Reproduction in Carnivores], a unit specializing in pet breeding assistance. Emmanuel Fontaine is also qualified at the European College for Animal Reproduction (ECAR) and completed his PhD in 2012 on the use of GnRH agonists in canines. From September 2011 to September 2018, he worked as Technical Services Veterinarian for the PRO team at Royal Canada. He then was in charge of Scientific Communication for the Americas until August 2022. He now works as Senior Scientific Communications Veterinarian for Royal Canin North America.