Pet Nutrition Stages
ASPCA Pet Nutrition and Science Advisory Service
Dogs and cats begin to show visible age-related
changes when they are seven to twelve years old.
Before those changes become visible, though, there
are metabolic, immunologic and body composition
changes that slowly begin. Some of the changes are
unavoidable. Others can be managed with diet. If,
however, the timing of those dietary changes waits
until the overt signs are visible, the opportunity to
prevent or slow those changes is past.
Nutritional adjustment should begin early, but the exact age in dogs is not as simple as it is in
cats. Cats should start eating a senior diet at about 7 years of age. The age for dogs depends
upon the dogs size. Since smaller dogs live longer and don't experience the age-related
changes as early as bigger dogs, size is used to determine the time to change diets.
Small breeds or dogs weighing less than 20 pounds 7 years of age
Medium breeds or dogs weighing 21 to 50 pounds 7 years of age
Large breeds or dogs weighing 51 to 90 pounds 6 years of age
Giant breeds or dogs weighing 91 pounds or more 5 years of age
As a dog or cat ages, changes in body tissues may result in health issues, including:
deterioration of skin and coat
loss of muscle mass
more frequent intestinal problems
decreased ability to fight off infection
The main objectives in the feeding of geriatric dogs and cats should be to maintain health and
optimum body weight, slow or prevent the development of chronic disease and minimize or
improve clinical signs of diseases that may already be present.
Older dogs and cats have been shown to progressively put on body fat in spite of consuming
fewer calories. This change in body composition is inevitable and may be aggravated by either
a reduced energy expenditure or a change in metabolic rate. Either way, it is important to
feed a diet with a lower caloric density to avoid weight gain from fat and with a normal protein
level to help maintain muscle mass.
Studies have shown that the protein requirement for older dogs does not decrease with age
and that protein levels do not contribute to the development or progression of renal failure. It
is important to feed older dogs diets that contain optimum levels of highly digestible protein to
help maintain good muscle mass. Avoid "senior" diets that have reduced levels of protein.
Other special nutrients have been shown to be beneficial in older animals:
Increased vitamin E for senior cats. Antibody response decreases as cats age. Increasing the
intake of vitamin E in cats over seven years of age can increase their antibody level back to
levels seen in younger cats.
Gamma-linolenic acid (GLA). GLA is an omega-6 fatty acid that acts like an omega-3. It also
plays a role in the maintenance of a healthy skin and coat. It is normally produced in the dog's
liver. In older dogs, GLA levels may be diminished because the activity of the enzyme
responsible for its production decreases with age.
Fructooligosaccharides (FOS). Older dogs often have changes in the intestinal bacterial
population which can result in clinical signs of gastrointestinal disease (e.g. diarrhea). Senior
diets for dogs should contain FOS to promote the growth of beneficial bacteria at the
expense of detrimental ones.
Antioxidants. As dogs age, free radical particles accumulate and can damage body tissues
and contribute t © 2004 ASPCAo the signs of aging. Antioxidants such as vitamin E and
beta-carotene help eliminate the free radical particles. Senior diets should contain higher levels
of these antioxidant compounds to help nutritionally manage the free radical particles at the
cellular level. Antioxidants can also increase the effectiveness of the immune system in senior
cats and dogs.
Routine care for geriatric pets should involve the adherence to a consistent daily routine,
regular attention to normal health care procedures and periodic veterinary examinations for
assessment of the presence or progression of chronic disease. Stressful situations and abrupt
changes in daily routines should be avoided. If a drastic change must be made in an older pet's
routine, attempts should be made to minimize stress and to accomplish the change in a
© 2004 ASPCA
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