Canine infertility has always been one of my favorite topic. Certainly because of the fact that, even if the most common causes in canines are today well-known in veterinary medicine (FYI mistiming of ovulation & poor semen quality), there are still some cases where reaching a definitive diagnosis is tricky. Few years ago we were therefore facing a dilemma: when timing of ovulation has been performed AND the male’ semen quality has been evaluated and judged ok, what’s left if infertility remains a problem still ?
Ultrasounds: a great asset in canine gynaecology
Genital ultrasounds are an essential tool for us in veterinary medicine when it comes to canine infertility, gives us a way to evaluate the inside part of the genital tract and believe me, ovarian/uterine diseases are NOT uncommon in bitches suffering from infertility. Don’t hesitate to take a look at the video of our previous webinar on uterine diseases in bitches to have a better idea !
However, for certain cases, even after a thorough ultrasound examination, everything looked normal and it was still hard to understand what was causing the infertility issue in these breeding individuals.
Endometritis in canines?
When you are stuck like this, always important to take a look at what is done in other species. Physiology might be different for sure (remember, canines are unique) but still, for us this has always proved to be inspirational. And we did look at what was done in the mare, the cow,… and our attention got caught on something called “endometritis”. To make it short and super-simple: endometritis = inflammation of the inner part of the uterus (called “endometrium”). This inflammation creates an hostile medium for the sperm, the egg, the embryo… leading therefore to infertility. In mares a diagnosis was generally obtained after performing a uterine cytology or biopsy. Not something done in routine practice at the time in canines, but we were starting to use more and more genital endoscopy that would allow us to perform these kind of samples. So we thought we could give it a try to see if this was also be an issue in breeding bitches. Turned out it was indeed!
Fig 1: The inner part of the uterus is called the endometrium and is inflammed in case of endometritis
Lots of unanswered questions still but great hopes for the future
It is now possible to expand on the disease’s definition: endometritis in bitches = an inflammation of the inner part of the uterus that is not discernable under ultrasounds. We published a first paper on the topic in 2009 (see abstract here ) and recently another team confirmed our initial findings: in their study, 42.6 % bitches suffering from unexplained infertility (see their abstract here) were diagnosed with endometritis.