Many dog breeders have heard of (or seen) a dog pass out during a tied breeding. Is this a normal occurrence, or a sign of a dangerous health condition?
Under normal conditions, no dog should faint. Dogs that do faint often have severe underlying medical conditions, and should be taken to a veterinarian right away. However, if the stud’s heart is normal, fainting while breeding should be understood as a (rare) reaction to the excitement of mating. Though fainting is not a “desirable” attribute in a stud dog, it should not be a deterrent.
According to many scientists, the difference between stress and excitement is solely our emotional outlook- in the brain; both scenarios trigger the same flood of neurotransmitters. Our blood pressure and heart rate skyrocket, and our bodies are ready to fight, flee… or faint?
In the book “Zoobiquity,” the author argues that all animals have THREE responses to emotional stimuli- fight, flight, or faint. Rather than expending huge amounts of energy running or fighting, many animals choose to hold very still or go limp. This slowing of the heart is a natural response to stressful situations, known for years in the veterinary community as “alarm bradycardia.” At the extreme end of this lowered heart rate and blood pressure, any animal would pass out- and many do. There are several documented cases of animals fainting during an emotional ordeal- Darwin witnessed a canary that fainted every time his cage was cleaned! The healthiest of dogs can faint from the stress of a blood draw, or many other “frightening” occasions. It’s a physical response to the powerful flood of hormones released by the body.
Why should mating be any different? In many species of animals (humans included) there are instances of fainting during or right after orgasm. In fact, many horses are quite well known “fainters.” My family’s horse ranch once had a stud that fainted every single time he was bred. Two mattresses were placed astride the female so that when he fell, he didn’t hurt himself. This horse’s owners didn’t know they had a fainter, but it made a great viral YouTube video.

Maybe too excited.
Photo Dave Walker
So, fainting during the tie may be very normal for some dogs- especially their first time. They’re nervous, horribly hormonal, and their blood pressure fluctuates. So what should you do if your dog passes out? Wait for him to wake up- don’t smack him, or startle him awake- he’s already stressed enough.
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September 1, 2012
Breeding Dogs, Health and Science