NEARLY 100 veterinary surgeons,
animal behaviourists, neurologists
and specialist journalists from 17
countries attended a symposium
hosted by Nestlé Purina in Vevey,
Switzerland, last month to hear
about canine cognitive function.
Eight speakers addressed aspects of Advances in managing canine
brain ageing, covering
topics including
geriatric medicine, brain
physiology, diet and
canine cognitive
dysfunction (CCD).
The audience also
heard about a new
nutritional intervention
using a specific fat
source – medium chain
triglycerides (MCTs) –
which has been proven
to improve significantly cognitive
function in the senior dog, resulting in
increased attention, memory and
learning capacity.
The meeting was chaired by
Professor Adám Miklósi, a Hungarian
behaviourist renowned for his research
with wolves, and addressed by, among
others, British veterinary surgeon Sarah
Heath, president of the European
Society for Veterinary Clinical Ethology,
who spoke on CCD and highlighted the need for practitioners to incorporate a
programme for the early detection of
canine dementia into their geriatric
clinics.
Dr Jill Cline, senior research scientist
at Nestlé Purina in Saint Louis, USA,
reported on efficacy studies which had
shown that when senior dogs were fed with a natural source of
MCTs that provide
metabolites readily used
by the ageing brain,
they demonstrated
improved attention,
memory, learning
capacity and an ability
to adapt to novel
situations.
Claire Guest, CEO
of the UK charity,
Cancer & Biodetection Dogs, based in
Aylesbury, Bucks., presented a case study showing that feeding a diet with
MCTs had enabled a cancer detection
dog to extend its working life.
A paper soon to be published in the
British Journal of Nutrition indicates that
incorporating MCTs in the diet of a
senior is an effective way to help delay
the cognitive effects of ageing and
improve the quality of life for both the
dog and its owner. Although further
studies are needed to confirm this, it is also possible, Dr
Cline said, that
feeding MCTs will
have positive effects
on dogs with mild to
moderate CCD.
Dr Lizzie Parker,
Nestlé Purina’s head
of the veterinary
channel, Europe,
said that, similar to
trends seen within
the human
population, and
thanks to
improvements in
veterinary medicine,
nutrition and
preventive health-
care, the European
canine population is
becoming older with
up to an estimated
50% of dogs now
regarded as “senior”.
As a result, there
is an increasing
diagnosis of age-
related diseases and also a higher incidence of behavioural
problems related to ageing.
Dr Xavier Manteca Vilanova, from
the Barcelona veterinary school, said
that from the perspective of owners,
more than 40% of dogs and cats
suffered from behavioural problems,
adding: “Behavioural medicine should
be seen as a fundamental part of our
professional activity.”
He said that the relationship
between nutrition and behaviour was
two-fold: nutritional factors had a
significant effect on behaviour; and the
nutritional status and health of animals
could be affected by their behaviour.
With increasing age, some dogs develop a
neurogenerative disease
that is characterised by
a gradual decline in
cognitive function
(CCD). Interest in this
has grown rapidly as it
has been realised that it
has many similarities
with Alzheimer’s disease
in humans. Clinically,
CCD may cause
disorientation, altered
interactions with people
or other animals,
alterations in the sleep-
wake cycle, changes in
activity level and house-
soiling.
Dietary treatment
has been based on the use
of antioxidants and mitochondrial co-
factors that may decrease the deleterious
effects of free radicals. There is ample
evidence, he continued, suggesting that
free radicals play an important role in
ageing; the brain is particularly
susceptible to the effects of free
radicals, as it has a high rate of oxidative
metabolism, a high content of lipids
and a limited ability for regeneration.
There are several studies showing
that an antioxidant-enriched diet
improves cognitive performance in
senior dogs and recent work has shown
that long-term supplementation with
medium chain triglycerides can improve
cognitive function in aged dogs.
The underlying mechanism appears
to be an increase in the circulating levels
of ketones which provide the brain with
an alternative energy source.
Pressures
Dr Gérard Muller, a French veterinary surgeon who specialises in pet
behaviour, said that ageing animals were
subject to two types of pressure: that
caused by their physical ailments and
that caused by their lack of motivation.
“Motivation is a reaction by the
body to restore its equilibrium,” he said.
“The degree of motivation depends on
how strong the imbalance is, whilst the
search for a solution is informed by past
experience.
“Thus, when an
animal is hungry, its
body is no longer in a
state of equilibrium,
and foraging
mechanisms will be
triggered until the
sensation of
imbalance disappears,
i.e. until its hunger has
been sated. Likewise,
when an animal feels
insecure, it gears its
behaviour toward
seeking shelter and
restoring its sense of
safety.
“Ageing
individuals gradually
learn to resign
themselves to minor imbalances. As the ageing process
progresses, the imbalances they tolerate
become more and more severe.
Powerless to react to ever more serious
physical ailments, they grow increasingly
resigned. This is one of the mechanisms
of pathological inhibition classically
observed in depression. It is thus easy
to understand how physical ailments can
exacerbate ageing.”
Stating that cognitive disorders
could often lead owners to react in less
than sympathetic ways, he said that the
ageing dog often saw its environment
becoming more and more hostile. “Its
social relationships deteriorate and it
finds fewer and fewer reasons to
motivate itself.”
Cognitive creatures
Dr Karen Overall, from the University
of Pennsylvania school of medicine,
discussed advances in understanding
canine learning, memory and cognition and also the impact of diet on brain
metabolism.
Urging caution in labelling
behaviours, she said that dogs were not
wolves and hadn’t been for a long time.
“They are cognitive creatures and by
understanding the factors that affect
how dogs learn, we can contribute to
preventing behavioural problems and
provide data-based humane care.”
Dr Overall said dogs could do
“observational learning” by watching
both humans and dogs. “We don’t
actually know much dogs can learn, but
recent published work
from the emergent field
of cognitive studies in
non-laboratory canines
should give us pause.
We now know that
dogs can take their cues
from dogs or humans
about hidden objects
and communicate this
information to other
dogs.
Making deductions
“Dogs appear to have the
ability to ‘fast map’ – to make
deductions about object class and name
without having learned them directly –
and to communicate this ability to
humans. ‘Fast mapping’ is the first stage
of language acquisition in humans.
Recent work shows that dogs make the
same classes of cognitive errors in
learning as do young children.
“For decades we have used dogs to
help those who cannot see and those
who require help opening doors, turning
on lights, picking up objects and getting
dressed or out of bed. Dogs scan the
post, luggage, planes, cars, and people
for explosives and contraband. Dogs
jump from helicopters to rescue the drowning and search disaster sites for
both the living and the dead.
“All of these tasks are deeply
cognitive, and while the dogs learn the
required responses that we teach them,
they also seem to learn and
communicate about what they learn as
much as we permit them to do so.
“The key to understanding all
learning and cognitive changes –
whether they are beneficial or
pathological – is to understand how
such processes are effected at the
molecular level. Once we understand the role that various
regions of the brain
and learning in those
play, it’s a simple step
to think of helpful
interventions for
enhancing learning
and, perhaps, cognitive
abilities. “Meanwhile,”
Dr Overall concluded,
“we probably owe all
our dogs an apology.
They are clearly
smarter than we
thought and have likely been telling us that for a long
time.”
In a second presentation, Dr Overall
said that impaired glucose metabolism
could contribute to Alzheimer’s disease
and other tauopathies. The brain has a
high energy need but a low storage
capability and glucose insufficiency
could be an issue in a number of
pathological conditions in which
cognition is impaired.
It had been postulated that if we
could enhance glucose uptake and
improve energy metabolism in neurons
we would have neuroprotection. “Diet
and supplements may be able to play a
huge role in how we prevent and treat neuronal assaults,”
she said.
Diagnosing CCD
“Canine dementia is
a medical condition
but in most cases
there is a lack of
recognisable clinical
symptoms and the
signs that lead to
accurate diagnosis
are almost entirely
behavioural,” said
Sarah Heath, who
runs the Behaviour
Referrals Veterinary
Practice in Chester.
“It requires prompt and appropriate
veterinary attention,” she said. “The
most effective way of increasing the
detection rate is to include a behavioural
questionnaire in routine geriatric
clinics.”
Quoting a US study which found
that 48% of dogs eight years of age or
older showed some signs of CCD
(known more commonly in the States as
CDS – cognitive dusfunction
syndrome), she listed the four main
categories of presenting signs as:
disorientation, changes in social and
environmental interaction, changes in
the sleep/wake cycle, and breakdown in
house-training.
“As the ageing process takes its toll
on a dog’s heart and brain, some
changes in behaviour and personality are
almost inevitable and it is important to
be able to differentiate between cases
where the animal is simply slowing
down out of necessity and those where
the animal is finding it increasingly hard
to function at a social level.
“In some cases behavioural changes
in old dogs will noticeably resemble the symptoms of Alzheimer’s disease in
people. Lack of connection between
behaviour and context is a classic sign
of dementia and many owners have
reported that their dog seems like a
stranger in its own home.
“In cases of canine cognitive
dysfunction, post mortems have shown
similar neuropathological lesions to
those seen in people with Alzheimer’s
disease and dementia and there is no
doubt that this condition is part of
mainstream medicine.”
Ms Heath concluded: “Detecting the
symptoms of this condition at the
earliest opportunity will enable these
dogs to receive appropriate veterinary
care and maximise the benefits of
therapy in terms of increased quality
and duration of life.
“Practices can vastly improve their
service to geriatrics by incorporating a
programme for the early detection of
canine dementia into their geriatric
clinics.”
- Purina reports that it will have
products containing MCTs available for
sale through veterinary practices in the
very near future.
