(Originally written for DogWatch, a newsletter for the general public from the Cornell University College of Veterinary Medicine)
When I took my rottweiler in for her annual check-up, I asked my veterinarian about bloat because her litter mate died from it and I wanted to know what I could do to prevent it. We discussed different feeding strategies, but he also told me fearful dogs were at higher risk. Can my dog’s personality really affect her health?
The study of gastric dilatation-volvulus (GDV or bloat) in dogs conducted by Lawrence Glickman and his team of researchers at the Center for the Human-Animal Bond at Purdue University did indeed show that dogs judged nervous or fearful by their owners were at higher risk than calmer, more easy-going ones. But how could this be? Unfortunately currently studies of disease or injury don’t take the role of the animal’s behavior or bond with the owner into account. But hopefully the increased interest shown in the links between behavior and health by human health professionals and the general public will stimulate more research in this aspect of veterinary medicine too.
Beyond that though, we can get some hints regarding what might occur in domestic animals from what we know happens in wild ones. When frightened by a predator, many wild animals will immediately empty their bladders and defecate. Among the benefits of doing this, it decreases their weight and frees up all the energy previously used for digestion and stool and urine production. That in turn enables threatened animals to fight or run more efficiently.
Consequently the normal fear response involves a period of hypermotility or increased activity of the gut to empty it, followed by hypomotility which enables the animal to channel maximum energy to the skeletal muscles for flight or fighting. In the wild, prey animals which finds themselves in this situation usually either gets away from predators or get caught and eaten within a relatively short time. If the animal gets away, normal gut motility becomes re-established and may remain so for a fairly long time. Although nature films sometimes give the impression that animals spend most of their time fighting or fleeing predators, such encounters make up a comparatively small part of the wild animal’s day.
Compare this to the life led by the average timid dog in a complex suburban environment. Every time fearful Freddy hears a strange noise during his owner’s absence, he wants to run and hide. Shortly after his owner goes to work, the sound of the school bus sets him off. His ancestral brain sends a message to the smooth muscle of his gut to empty out and prepare for the great fight or escape. However house-trained Freddy wouldn’t dream of doing that, or maybe his gut is empty because he only gets fed in the evening. Whatever the reason, the hypermotile phase comes to a screeching halt when he bolts for the door and begins barking frantically.
Freddy survives that assault and his gut starts functioning normally again. But then an hour later the mail arrives. An hour after that, the UPS man leaves a package. Then the kids next door start playing ball, and a dog starts barking on the next block. Each time something frightens him, Freddy’s gut speeds up, shuts down, then starts up again. Perhaps after repeated episodes of this, it loses its ability to contract normally and dilates, just like a balloon that’s been repeatedly inflated and deflated eventually loses its elasticity.
But what about dogs like Clementine who drool, vomit, or get diarrhea when they get scared? Instead of their guts shutting down, they go into overdrive. In reality, Freddy’s and Clementine’s responses probably represent variations on the same theme. Freddy can muster the courage to get beyond the gut-emptying freeze state, but Clementine remains stuck there. Perhaps her gut just keeps churning until it can’t churn any more.
In both cases though, when the dogs eat that night the digestive juices flow as usual but their stomachs may not contract normally to mix things and aid digestion. In that case, gas may build up. At some point before or during this process, and added by a body type that lends itself to this, the stomach may flips and GDV results.
Again, this all remains speculation based on wild animal behavior. Still, it serves as yet another good reason to keep our dogs’ minds as healthy as their bodies.