• The incidence of GDV has increased by 1,500% over the past 30 years.
• Thirty percent of all GDV cases are fatal. In contrast,
dogs properly treated have an 80% probability of surviving a
bloat episode.
• The recurrence rate of GDV in dogs conservatively treated for bloat
i.e., without surgery, approaches 100%. The recurrence rate following
gastropexy is less than 5%. Always insist on immediate surgery for your
Leonberger, do not bring your dog home without corrective surgery.
•
Personality is a major predictor of GDV, the happy,
easy-going dog has a lower risk of GDV. He suggests using behavior
modification with anxious, fearful dogs.
• The incidence of GDV increases with advancing age. The increased
risk begins at three years of age.
•
Do not breed dogs if a first-degree relative has
bloated and do not breed dogs that have bloated. Having a grandparent,
parent or sibling with GDV increases the risk of bloat.
• Males and females bloat almost equally.
•
Spaying and neutering have no effect
on the incidence of GDV.
• Dogs characterized by their owners as chronically
underweight are at higher risk than dogs characterized as average weight
or even overweight.
•
The faster a dog eats, the greater the risk of bloat. This
increased risk may be related to gulping air while eating. Reduce the
eating speed of your Leonberger.
• Seventy percent of bloat cases occur late at night or
early in the morning. Dr. Glickman is investigating a swallowing
disorder as a possible contributing factor.
• There is a relationship between dogs with intestinal gas and dogs
that bloat. Dogs that belch often have a 60% increased risk of bloat.
Dogs with frequent bouts of flatulence have a 20% increased risk.
•
Elevating the food bowl increases the risk of GDV.
• Dogs fed only dry food are at increased risk, while dogs fed a mix
of dry food with table scraps are at decreased risk.
•
Dogs fed dry dog foods preserved with citric acid
were at a higher risk of bloat; moistening the dry dog food containing
citric acid further increased the risk.
• Feeding dry food containing rendered meat with bone among the first
four ingredients decreased a dog’s risk of bloat by 53%.
•
Feeding multiple small meals reduces the risk of
bloat.
• Having water available at all times reduces the risk.
• In high-risk breeds (like Akitas), consider having a prophylactic
gastropexy done when the dog is spayed or neutered. The recovery is not
very different than for sterilization alone, and the cost of the
procedure is considerably less than an emergency surgery. (Approximately
$3,000 compared to an additional $200.)
Is a raw food diet
a factor in prevention of this disease? We will have to wait until Dr.
Glickman completes his dietary-management study. The “Natural Akita”
email list, which is comprised of advocates for the raw food diet, claim
one case of bloat in an Akita since its inception in 1997--that could be
coincidence.
Is
Bloat A Neurological Disease?
My
experience with bloat ended successfully for my Akita, Tootsie--she
expanded like a balloon five hours after eating, was rushed to the
emergency hospital two blocks from home and underwent successful
gastropexy. Her surgeon was amazed at the complete lack of motility; he
mentioned that in all GDV surgeries he had performed on various breeds,
gastrointestinal motility was lacking in each dog. I assisted the
veterinarian in washing undigested food from Tootsie’s stomach, food
that she had eaten three days earlier.
His statement led
me to research “motility,”
the propulsion of food along the length of the digestive tract. What
activated the smooth muscle contractions and why would this action
cease, leaving undigested food in the stomach? Time out for a simple
anatomy lesson!
The dog's nervous system is comprised of the central and
peripheral/autonomic nervous systems. The central nervous system
consists of the brain and the neural tube running the length of the
spinal cord. The brain is the body's central computer, analyzing and
processing all information both internally and externally. Based on
external stimuli, the brain decides a course of action, and relays the
information through the central nervous system to the body or to a
specific organ. Sensory nerves carry information to the brain and spinal
cord; motor nerves carry signals back to the body, to spur movement of
the muscles, or to stimulate glands into activity.
Dr.
Zen of the Gastrointestinal Research Laboratory, Gunma University,
Maebashi, Japan
has
been studying motilin, which is an important factor in controlling the
pattern of smooth muscle contractions in the upper gastrointestinal
tract. Motilin is
considered a hormone—a “housekeeping hormone,” which is secreted into
the circulation at intervals of every one hundred minutes, to sweep out
undigested material from the stomach and small intestine. Motilin also
stimulates secretions of bile and pancreatic enzymes into the duodenum.
Very little is
known about the control of motilin. Apparently, it is stimulated by
cholinergic neurons in the enteric nervous system, which is a part of
the autonomic nervous system.
The enteric nervous system controls
all of the digestive processes from the secretion of motilin, to the
propulsion of food through the gastrointestinal tract. Enzyme secretions
from the pancreas and bile from the gallbladder are controlled by
motilin. The enteric nervous system contains sensory neurons,
inter-neurons, and motor neurons. Its circuitry can autonomously sense
the tension, and the chemical environment in the gut and regulate blood
vessel tone, motility, secretions, and fluid
transport. The system is itself governed by the central
nervous system.
Organophosphate insecticides
like Dursban,
Malathion,
and Diazinon,
and carbamate insecticides (Carbaryl
and Propoxur), as well as the latest family of nicotinoids (nicotine
derivatives), are
all neurotoxins.
These chemicals
work by interrupting the electrochemical processes that nerves use to
communicate with muscles and with other nerves. A key chemical in
communication between neurons is called a neurotransmitter—acetylcholine
is the neurotransmitter involved in muscle contractions. Acetylcholine
(produced by the body) is used to "fire" the neuron, and then is
inhibited by an enzyme called cholinesterase. In a healthy nervous
system, acetylcholine passes a signal (fires) between one neuron and
another, or between a nerve and a muscle receptor. The enzyme
cholinesterase is released and binds to the acetylcholine, allowing the
nerves to rest. Cholinesterase, however, is not unique to insects--it is
also a component of the canine nervous system. (The enteric nervous
system uses the major neurotransmitters, like acetylcholine, serotonin,
Motilin.)
The nicotinoid insecticides like imidacloprid,
activate the nicotinic acetylcholine receptor, but do so steadily, since
they are insensitive to the action of cholinesterase. This persistent
activation leads to an over stimulation of cholinergic synapses, and
results in hyper-excitation, convulsions, paralysis, and the death of
the insect.
The
organophosphate group of insecticides
inactivates cholinesterase to prevent the degradation of
the neurotransmitter acetylcholine; this results in a constant flow of
acetylcholine at the synapse.
The carbamate
insecticides mimic acetylcholine--as the acetylcholine builds up, the
muscles of the body become over-stimulated, leading to paralysis and
death.
Neurotoxic pesticides
are highly toxic to mammals with a chemical characteristic that leads
them to dissipate very slowly once introduced to the body. They are used
directly on dogs, as well as in their environment. The assumption is
that small amounts are sufficient to kill an insect but will not harm a
dog, but is it possible to really limit exposure? These chemicals are
now ubiquitous in our environment. For example, the Environmental
Protection Agency estimates that 60 million pounds of organophosphate
pesticides are applied within the United States every year. Chlorpyrifos
is the most widely used insecticide in the Chesapeake Bay
district. Recent studies show that this organophosphate chemical is
consistently present in the air, rain and surface waters of the
Chesapeake Bay region, suggesting a
long environmental half-life.
