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Small animal clinical nutrition: An iterative process

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  • Veterinary Nutritional Consultations, inc
CLINICAL IMPORTANCE
The public has become increasingly more aware of the impor-
tance of nutrition to health during the past four decades as a
result of the growing recognition that food is associated with
disease processes such as coronary artery disease, hypertension,
obesity, diabetes mellitus and cancer. Healthy People 2010 is a
comprehensive set of disease prevention and health promotion
objectives for the United States. Healthy People 2010 uses 10
leading health indicators that reflect the major health concerns
in the nation at the beginning of the 21st century.These indi-
cators were selected based on their importance as public health
issues and their ability to motivate action and provide data to
measure progress against specific goals. One of the focus areas
is nutrition, especially overweight/obesity conditions (Healthy
People 2010).
The discipline of veterinary nutrition and its relationship to
the practice of veterinary medicine have benefited from these
changes. Food animal veterinarians have long recognized that
no aspect of the production enterprise has more impact on
health and production than nutrition; many health problems
areassociated with inadequate feeding programs. Food animal
veterinarians recognize that optimizing feeding programs
improves food animal health and productivity and, as a result,
the economic status of producers. Food animal veterinarians
who provide their clients with high-quality production medi-
cine programs become unbiased nutritional consultants.
Similarly, small animal practitioners must improve their
nutritional counseling skills because they cannot trulymeet
their patients’ health needs without optimizing nutrition.
Small animal veterinarians can improve the quality of medi-
cine delivered to their patients by knowledgeably and system-
atically addressing the nutritional aspects of each case, whether
the goal is treating or preventing disease. Veterinarians must
emphasize health maintenance and wellness strategies for
companion animals to provide the most beneficial service.
Total disease prevention requires lifelong dedication to proper
nutrition, immunizations, dental care and parasite control pro-
grams. Nutritional factors are a cornerstone in maximizing
health, performance, longevity and disease prevention.
Nutritional counseling and intervention, however, are benefi-
cial only if done properly.
Veterinarians and their health care teams have considerable
influence on the foods clients feed their pets. A study conduct-
ed by Veterinary Economics in 1990 found that 87% of veterinar-
ians felt that offering nutritional services improved their prac-
tices (Gants, 1990). Ninety-four percent of these veterinarians
said that their clients were somewhat or very receptive to nutri-
tion-related information. A 1995 study conducted by the
American Animal Hospital Association found that 54% of pet
owners interviewed sought veterinary advice on pet foods at
least once and 43% had received a recommendation from their
veterinarian on which manufacturer’s pet food to feed their pup-
pies or kittens. Seventy percent of the latter group fed the brand
of food recommended by their veterinarian (AAHA, 1995).
Chapter
1
Small Animal
Clinical Nutrition:
An Iterative Process
Craig D. Thatcher
Michael S. Hand
Rebecca L. Remillard
“Things should be made as simple as possible, but not simpler.”
Albert Einstein
The word recommend means to counsel or advise (American
Heritage Dictionary). The implication is that the advice pro-
ceeds from actual knowledge of the subject. Veterinarians
should know how food needs vary with each lifestage, with
mental, physical and environmental stresses and with diseases.
Causes and effects of dietary imbalances should be considered
so that the resulting disorders can be prevented or diagnosed
and treated. Veterinarians should also be familiar with the var-
ious pet foods available to help clients choose the most appro-
priate ones. Veterinarians also need to understand the benefits
and shortcomings of various feeding methods. After a feeding
plan has been instituted, veterinarians need the skills to moni-
tor the program to assess and reassess outcomes and to modify
the feeding plan when necessary. The primary goal of this
chapter is to provide practicing veterinarians, veterinary techni-
cians and students with the basic problem-solving processes
needed to successfully manage the nutrition of companion ani-
mal patients.
The Two-Step Iterative Process
of Clinical Nutrition
Abrief review of instructional systems design (ISD) is in order
to better understand iterative (repetitive) processes. ISD
emerged after World War II as a set of recognized standard
procedures used to develop well-structured materials in
response to the need for more efficient training techniques
(Mooreand Kearsley, 1996). ISD embodies various perspec-
tives onlearning,teaching, systems theory, behavioral psychol-
ogy, communications and information theory. The ISD model
breaks instructioninto a series of phases or steps with defined
procedures; adefined service or product must be delivered at
each step. Steps include: 1) design, 2) development, 3) imple-
mentation, 4) evaluation and 5) analysis. Then, the process
repeats itself as a continuous loop and may involve many cycles.
The American College of Veterinary Nutrition (ACVN) has
recommended that nutrition problem solving include assess-
ment of the patient, the food and the feeding method (Bauer et
al, 1995).
Figure 1-1 depicts the iterative process used in this book.
The first step is patient assessment, which allows the determi-
nation of the patient’s key nutritional factors and their levels
(the concept of key nutritional factors is described below).
Determination of the key nutritional factors is the basis for the
second step: the feeding plan.The feeding plan includes recom-
mendations for food and feeding methods. If assessment of the
current food and feeding methods indicates that they are
appropriate, the current feeding plan can remain in place.
However, if the assessment indicates otherwise, a new feeding
plan should be formulated and implemented.
After a suitable period of time (the length of which depends
on the patient’s condition), the two-step process is repeated to
determine the appropriateness or effectiveness of the new feed-
ing plan. Thus, the patient is reassessed and, if necessary, a new
feeding plan is developed and implemented. This is the itera-
tive or repetitive part of the process. Any number of iterations
of the two-step process can occur, depending on the needs of
each patient. A critically ill patient may need to be reassessed
every fewhours, whereas a normal adult dog or cat may be
reassessed annually. The subsequent reassessment of the patient
at each cycle is also referred to as monitoring.This information
is discussed under the heading of reassessment in the chapters
that deal with patient assessment and feeding plans.
PATIENT ASSESSMENT
The goal of patient assessment is to establish a dog’s or cat’s key
nutritional factors and their target levels in light of its physio-
logic or disease condition. The patients key nutritional factors
are the benchmark for assessing the animal’s food and selecting
afood. Assessment of dogs and cats to determine their key
nutritional factor status should be a structured process that
includes: 1) review of the history and medical record, 2) physi-
cal examination and 3) laboratory tests and other diagnostic
procedures (Remillard and Thatcher, 1989). These first three
steps determine the patient’s physiologic state and medical
diagnosis and are the basis for the fourth step, which is the
determination of the key nutritional factors and the estimation
of their target levels.
Obtain an Accurate History and
Review the Medical Record
Obtaining the animal’s history and reviewing the medical
record help determine the nutritional status of the patient. The
signalment is partof the history and defines the patients phys-
iologic state and includes: 1) species, 2) breed,3) age, 4) gender,
5) reproductive status, 6) activity level and 7) environment.
Acomplete history should also include questions about the
pet’s weight and therapies (medical, surgical, etc.) that may
affect appetite, nutrient metabolism or both. An accurate
Small Animal Clinical Nutrition
4
Figure 1-1. The two-step process of veterinary clinical nutrition.
description of the current feeding plan, including the animal’s
food, eating and drinking habits and feeding methods should
be obtained from the client. Intakes of treats and nutritional
supplements should be recorded.
Review of the medical record provides objective historical
information and documents the pet’s previous health status,
health maintenance procedures that were performed and med-
ications that were prescribed. Veterinarians should evaluate this
information to determine if any of these factors are related to
the animal’s current nutritional status.This review permits early
nutritional intervention in the treatment of established malnu-
trition (under- or overnutrition) and in the prevention of mal-
nutrition in individuals at risk (Box 1-1).
Apatient’s food is usually changed because of altered
requirements or alterations in nutrient intake, digestion,
absorption, metabolism, excretion or a combination of these
factors. Knowledge of normal nutritional physiology and of dis-
eases and their nutritional pathophysiology is important to
identify patients at risk for malnutrition. The history and med-
ical record are tools to help identify these risks.
Conduct a Physical Examination
Athorough physical examination can help define an animal’s
nutritional status and identify diseases that may have a nutri-
tional component. Physical findings should be recorded in the
patientsmedical record. Veterinarians should examine each
body system for problems that are responsiveto nutritional
intervention. Ananimal’s body condition will likely reflect
abnormalities of major organ systems.
Body condition can be subjectivelyassessed by a process
called body conditionscoring. In general,this process assesses a
patient’s fat stores and, to a lesser extent,muscle mass. Fat cover
is evaluated over the ribs, down the topline, around the tailbase
and ventrally along the abdomen. Body condition score (BCS)
descriptors have been developed with respect to the species
(dogs and cats) and age of the patient (Figures 1-2 and 1-3).
Score descriptors vary due to the structural differences
between species and between young and adult pets. The scores
range from 1 to 5 with 1 being very thin and 5 being grossly
obese. A body condition score of 3/5 is generally referred to as
being ideal. An “ideal” body condition, however, depends on
the dog’s or cat’s lifestage,lifestyle and intended use. For exam-
ple, a BCS of 2/5 to 2.5/5 may be desirable for a racing grey-
hound, whereas a BCS of 3.5/5 might be better for a pregnant
queen at the end of its first trimester to help support the
upcoming lactation. A BCS of 2.5/5 to 3/5 is probably ideal
for most mature dogs and cats for optimal health and resultant
longevity. Thus, overall, an ideal BCS is a range of numbers
rather than simply a “3/5.”
Body condition scoring reasonably estimates an animal’s
body composition. Studies assessing scorer repeatability and
variations between scorers have found agreement between 80
to 90% of the measurements (LaFlamme et al, 1994; Graham
et al, 1982; Croxton and Stollard, 1976; Burkholder, 1994).
Research with cats found a correlation of 0.9 or higher
between BCS and body composition predicted from mor-
phometry (LaFlamme, 1993). Veterinarians should routinely
assign BCSs, obtain body weights and record both in the med-
ical record.
The patient’s body weight can be compared with breed
standards (Appendix 14) or with the animal’s previous body
weight fromthe medical record. The patient’s pre-illness body
weight or usual body weight during health can serve as a stan-
dardfor determining the effect of illness onbody weight. Ahis-
toryof rapid weight loss and a reduced BCS mayindicate a
catabolic condition with a marked loss of lean tissue, dehydra-
tionor both. Ahistoryof progressiveweight gain and an
increased BCS mayindicate an anabolic conditionwith an
excessive accumulation of fat, water or both.
Conduct Necessary Laboratory Tests and
Other Diagnostics
No single laboratory test or other diagnostic procedure can
accurately assess a patient’s nutritional status. Routine complete
blood counts, urinalyses and biochemistry profiles, however,can
provide insight into the presence of metabolic disorders and
other diseases. Albumin concentration, lymphocyte count,
packed cell volume and serum total protein values may serve as
general indicators of nutritional status. Other chapters in this
textbook will discuss specific laboratory tests and other diagnos-
tic procedures that may help assess healthy and sick patients.
Serum protein concentrations in people provide an estimate
of long- and short-term changes in nutritional status and cor-
relate with morbidity and mortality (Giner et al, 1996). For
example, low serum albumin concentrations may indicate pro-
tein depletion due to chronic undernutrition or protein loss.
Shorter half-life serum protein concentrations such as prealbu-
min, transferrin, retinol-binding protein and fibronectin are
used in human medicine to assess short-term changes in nutri-
tional status. However, these tests have not been routinely
available in veterinary medicine. Although not used widely,
serum creatine kinase concentrations are elevated in anorectic
cats and decline after 48 hours of nutritional support. Serum
5
An Iterative Process
Malnutrition is defined as anydisorder of nutrition with inad-
equate or unbalanced nutrition. Many veterinarians and ani-
mal owners think only of nutritional deficiencies when they
hear the term malnutrition. Muscle wasting and a distended
abdomen in a starving third-world child or a heavily para-
sitized puppy is often our first mental image of malnutrition.
In first-world societies, however, malnutrition is usually due to
overnutrition or excessive intake of nutrients. Obesity due to
consumption of excessive levels of fat and calories is a com-
mon example of malnutrition in people and their pets. Another
example of malnutrition due to unbalanced nutrition is devel-
opmental orthopedic disease seen in rapidly growing large-
and giant-breed puppies as a result of excessive calcium and
energyintake. Malnutrition due to either nutrient deficiencies
or excesses can be harmful to dogs and cats.
Box 1-1. Malnutrition Includes Excesses.
Small Animal Clinical Nutrition
6
BCS 1. Very thin
The ribs are easily palpable with no fat cover. The tailbase has a promi-
nent raised bony structure with no tissue between the skin and bone. The
bony prominences are easily felt with no overlying fat. Dogs over six
months of age have a severe abdominal tuck when viewed from the side
and an accentuated hourglass shape when viewed from above.
BCS 3. Ideal
The ribs are palpable with a slight fat cover. The tailbase has a smooth
contour or some thickening. The bony structures are palpable under a thin
layer of fat between the skin and bone. The bony prominences are easily
felt under minimal amounts of overlying fat. Dogs over six months of age
have a slight abdominal tuck when viewed from the side and a well-propor-
tioned lumbar waist when viewed from above.
BCS 4. Overweight
The ribs are difficult to feel with moderate fat cover. The tailbase has some
thickening with moderate amounts of tissue between the skin and bone. The
bony structures can still be palpated. The bony prominences are covered by
amoderate layer of fat. Dogs over six months of age have little or no
abdominal tuck or waist when viewed from the side. The back is slightly
broadened when viewed from above.
BCS 5. Obese
The ribs are very difficult to feel under a thick fat cover. The tailbase
appears thickened and is difficult to feel under a prominent layer of fat. The
bony prominences are covered by a moderate to thick layer of fat. Dogs
over six months of age have a pendulous ventral bulge and no waist when
viewed from the side due to extensive fat deposits. The back is markedly
broadened when viewed from above. A trough may form when epaxial
areas bulge dorsally.
BCS 2. Underweight
The ribs are easily palpable with minimal fat cover. The tailbase has a
raised bony structure with little tissue between the skin and bone. The
bony prominences are easily felt with minimal overlying fat. Dogs over six
months of age have an abdominal tuck when viewed from the side and a
marked hourglass shape when viewed from above.
Figure1-2. Body condition score(BCS) descriptors for dogs in a five-point system.
7
An Iterative Process
BCS 1. Very thin
The ribs are easily palpable with no fat cover. The bony prominences are
easily felt with no overlying fat. Cats over six months of age have a severe
abdominal tuck when viewed from the side and an accentuated hourglass
shape when viewed from above.
BCS 3. Ideal
The ribs are palpable with a slight fat cover. The bony prominences are
easily felt under a slight amount of overlying fat. Cats over six months of
age have an abdominal tuck when viewed from the side and a well-propor-
tioned lumbar waist when viewed from above.
BCS 4. Overweight
The ribs are difficult to feel with moderate fat cover. The bony structures
can still be palpated. The bony prominences are covered by a moderate
layer of fat. Cats over six months of age have little or no abdominal tuck or
waist when viewed from the side. The back is slightly broadened when
viewed from above. A moderate abdominal fat pad is present.
BCS 5. Obese
The ribs are very difficult to feel under a thick fat cover.The bony promi-
nences are covered by a moderate to thick layer of fat. Cats over six months
of age have a pendulous ventral bulge and no waist when viewed from the
side due to extensive fat deposits. The back is markedly broadened when
viewed from above. A marked abdominal fat pad is present. Fat deposits
may be found on the limbs and face.
BCS 2. Underweight
The ribs are easily palpable with minimal fat cover. The bony prominences
are easily felt with minimal overlying fat. Cats over six months of age have
an abdominal tuck when viewed from the side and a marked hourglass
shape when viewed from above.
Figure1-3. Body condition score(BCS) descriptors for cats in a five-point system.
creatine kinase concentrations may become a useful marker for
assessing and monitoring nutritional status in animals
(Fascetti et al, 1997).
Results of a single measurement or test must be interpreted
cautiously, because over- or under-hydration can alter concen-
trations of these proteins. Diagnostics such as radiography and
ultrasonography, including echocardiography,may be indicated
to further characterize the health status of patients. Results of
laboratory and diagnostic tests should always be viewed in the
context of findings from the history, physical examination and
the patient’s medical record.
Determine the Key Nutritional Factors and
Their Target Levels
The concept of key nutritional factors is fundamental to the
practical application of clinical nutrition used in this text.
However,to better understand the basis for this concept, a brief
review of nutrient requirements vs. nutrient allowances pre-
cedes the description of key nutritional factors.
Researchers traditionally have used normal dogs and cats to
determine nutrient requirements. In the United States, the pri-
mary sources for minimum nutrient requirements of healthy
dogs and cats are the National Research Council (NRC)
Nutrient Requirement bulletins published in 1985 and 1986,
respectivelyand recentlyupdated as a combined edition (NRC,
1985; NRC, 1986;NRC,2006).The requirements published in
1985 and 1986 weredetermined by feeding dogs and cats puri-
fied diets rather than commerciallyavailable foods.These NRC
values, therefore, were minimum nutrient requirements that
had to be extrapolated to the types of foods normally fed to
dogs and cats. In 1993 and 1994, the Associationof American
Feed Control Officials (AAFCO) published recommended
nutrient profiles for dog and cat foods, respectively (Nutrient
Profiles for Dog Foods, 1993; Nutrient Profiles for Cat Foods,
1994).These nutrient profiles have been republished yearly and
are the official source for nutrient profiles for commercial dog
and cat foods in the United States.
The AAFCO nutrient profiles include safety factors similar
to those in the recommended dietary allowances (RDAs) that
have been established for people (NRC, 1989). These safety
factors compensate for changes in a food’s nutrient availability
due to ingredient and processing variables and for individual
differences in nutrient requirements within dog and cat popu-
lations. Because of these safety factors, the term “allowance” is
better suited to describe AAFCO values than “requirements.”
AAFCO values are adequate to meet the known nutrient
needs of almost all healthy dogs and cats and are a better
source of feeding recommendations for most dogs and cats
than are minimum requirements. The earlier NRC bulletins
published for dogs and cats in 1974 and 1978, respectively, also
included safety factors and therefore were actually
“allowances.” Besides recommendations for lower limits,
AAFCO prescribes upper limits for certain nutrients with the
obvious implication that some nutrient excesses can be harm-
ful. As with RDAs for people, AAFCO allowances for pet
food nutrient profiles are not necessarily optimal.
Instead of separate dog and cat editions, the recently updat-
ed NRC includes information about both species. It provides
nutrient requirements in three formats: minimum requirement,
adequate intake and recommended allowance (2006).
Minimum requirement is defined as the minimal concentration
or amount of a maximally available nutrient that will support a
defined physiologic state. Adequate intake is defined as the
concentration or amount of a nutrient demonstrated to support
adefined physiologic state when no minimum requirement has
been demonstrated. Recommended allowance is defined as the
concentration or amount of a nutrient in a diet formulated to
support a given physiologic state. The recommended allowance
is based on the minimum requirement with consideration for
the normal variation in bioavailability of the nutrient in typical-
quality feed ingredients. If no minimum requirement is avail-
able, the recommended allowance is based on adequate intake.
Like the old editions, the more recent NRC edition also
includes safe upper limit levels for a nutrient when data are
available (NRC, 2006).
Neither NRC nor AAFCO has established nutrient profiles
for geriatric dogs and cats and those with specific disease
processes.
Key Nutritional Factors
Keynutritional factors encompass nutrients of concern and
other food characteristics. The concept of nutrients of concern
greatlysimplifies the approachto clinical nutritionbecause
most commercial pet foods sold in the United States provide at
least AAFCOallowances of all nutrients. Thus, if a commer-
cial food is fed, veterinarians and their health careteams need
onlyto understand and focus ondelivering the target levels for
afew nutrients (nutrients of concern) rather than the 40 plus
nutrients currently recognized for cats and dogs (NRC, 2006 ).
Nutrients of concern encompass nutritional risk factors for
disease treatment and prevention as well as nutrients that are
key to optimizing normal physiologic processes such as
growth, gestation, lactation and physical work. The following
elements must be considered in determining key nutritional
factors and their target levels: 1) the patient’s lifestage and
physiologic state, 2) environmental conditions such as temper-
ature, housing and pet-to-pet competition,3) the nature of any
disease or injury, 4) the known nutrient losses through skin,
urine and gastrointestinal tract, 5) the interactions of medica-
tions and nutrients, if applicable, 6) the known capacity of the
body to store certain nutrients and 7) the interrelationships of
various nutrients.
Besides requiring specific levels of certain nutrients, some
patients haveother food-related needs. These needs might
include management of acute or chronic systemic acid-base
balance, maintenance of a specific urinary pH range, certain
kibble texture, a specific range of digestibility or osmolality,
avoidance of certain protein sources and presence of specific
ingredients. Some nutrients and ingredients that are added to
foods provide other non-nutritive functions that can be
important to health and performance. Thus, specific food
characteristics or factors other than the nutrient content may
Small Animal Clinical Nutrition
8
be important to consider. Information about such food char-
acteristics should be available from product manufacturers.
Pet food labels contain addresses and toll-free phone numbers
of the manufacturer.
Chapters 12 through 24 determine and list key nutritional
factors and their target levels for healthy dogs and cats. The key
nutritional factors and their target levels for dogs and cats with
specific disease complexes can be found in Chapters 25 through
68. For convenience, these chapters also contain levels of key
nutritional factors in commercial foods typically marketed for
use in patients with various medical conditions. Regardless of
which nutrients are considered as key nutritional factors, the
reader should understand the various ways nutrient needs are
expressed. Box 1-2 describes the methods and units for express-
ing an animal’s nutrient needs.
In summary, the primary goal of patient assessment is to
establish the patient’s key nutritional factor needs. The key
nutritional factors are the benchmark for assessing the adequa-
cy of a patient’s food. Additionally, the results of patient assess-
ment are the basis for determining an appropriate feeding
method.
FEEDING PLAN
The feeding plan can be developed after the keynutritional fac-
tor needs havebeen determined. The feeding plan includes
what food or foods to feed and which feeding methods to use.
Thus, the first step is to assess the current food and to select the
best food to feed.
Assess and Select the Food
The primary components of food assessment should include: 1)
evaluation of the current food’s key nutritional factor content
relative to the patient’s needs (determined during Patient
Assessment, above) and 2) determination whether or not feed-
ing tests or clinical trials were conducted.
Determine the Food’s Key Nutritional Factor Content
The key nutritional factors and their levels for most of the com-
monly used commercial foods are listed in the food tables in the
individual chapters. In most instances, these profiles will pro-
vide the necessary information. If the key nutritional factor
information of the food in question is not listed in the food
tables, the manufacturer should be contacted for that informa-
tion. Pet food labels contain addresses and toll-free phone
numbers of the manufacturer.
Although much less convenient, there are other ways to
determine most of a food’s key nutritional factor content.
Many, if not most, key nutritional factors are nutrients. Box 1-
3describes various ways to determine the nutrient content of a
food. Box1-2 describes methods and units used in expressing
the nutrient content of food.
Key Nutritional Factor Comparison
Comparing a food’s key nutritional factor content with the
patient’s needs will help identify any significant imbalances in
the food being fed. If the patient’s current food is adequate (key
nutritional factors in balance with the patient’s needs) then the
food currently being fed can continue to be fed. However, if
important excesses or deficiencies exist, the patient’s current
food must be “balanced.”
There are numerous approaches to balancing foods. Some
are rather extensive (Boxes 1-4 and 1-5). This section will
review the most practical methods including: 1) food replace-
ment and 2) simple mathematical ration balancing (Pearson
square). Alternatively, veterinarians can contact a veterinary
nutritionist who accepts referrals. Both the ACVN and the
European College of Veterinary Nutrition (ECVN) have
diplomates who do referral work. Contact the executive direc-
tor of the ACVN to obtain a list of diplomates who do nutri-
tion referral work. Contact information for the executive direc-
tor can be found in the AVMA Directory or online at
www.ACVN.org.
When comparing a food’s key nutritional factor nutrient
content with a patient’s needs, methods of expressing nutrient
content of the food and nutrient requirements of the animal
must be compatible (same units). In this textbook, compatible
units are used in the food tables for comparing the food’s key
nutritional factor content and the patient’s target values. See
Box 1-2 for more details about how food content and animal
needs areexpressed.
Food Replacement
If food assessment indicates that an animalskeynutritional
factor requirements are not being met, the most practical way
to balance a food is to simplyselect a different food (i.e., one
that does a better job of meeting the patients requirements).
The most likely application of this method occurs when one
commercial food is substituted for another.If homemade foods
are being used, they can be replaced by appropriate commercial
foods or another homemade food if other recipes are available
(Chapter 10).
The process is straightforward and simple. The nutrient con-
tent of other foods is evaluated to see which food most closely
meets the animal’s requirements.Assuming comparable palata-
bility,the most acceptable food replaces the previous food.Case
1-3 demonstrates food replacement. This process is greatly
facilitated by the food tables in the feeding healthy dog and cat
chapters (Chapters 12 through 17 for dogs and 19 through 24
for cats) and the feeding clinically ill patient chapters (Chapters
25 through 68). These tables list the key nutritional factor tar-
gets and the key nutritional factor contents of commercial foods
commonly marketed for patients at various lifestages and those
having specific diseases.
Changing foods for most healthy dogs and cats is of minor
consequence. Some owners switch their pets from one food to
another daily. Most dogs and cats tolerate these changes.
However, vomiting, diarrhea, belching, flatulence or a combi-
nation of signs may occur with sudden, rapid switching of
foods, probably because of ingredient differences. It is prudent,
therefore, to recommend that owners change their pets food
over the course of at least three days. A seven-day period is even
9
An Iterative Process
Small Animal Clinical Nutrition
10
When comparing a patient’s nutrient requirements to a food’s
nutrient content to determine adequacy of the food, the same
quantifying units must be used to make the comparison meaning-
ful. The units used for expressing food nutrient content and patient
nutrient requirements are compared in Table 1.
PATIENT’S NUTRIENT NEEDS
The three methods for expressing an animal’s nutrient needs are:
1) dry matter, energy density defined and 2) energy basis and 3)
absolute basis.
Dry matter basis, energy density defined is the percentage or
quantity of a nutrient in the food’s dry matter that is needed by the
animal. This measure is the most common method of expressing
an animal’s nutrient needs. It describes what is required in a food
and indicates an animal’s nutrient needs. Dry matter refers to that
weight of the food remaining when the water content is subtract-
ed. (Tables 2 and 3demonstrate methods of calculating dry mat-
ter.) Dry matter values are most meaningful if the energy density of
the food’s dry matter is specified because most animals eat, or are
fed, to meet their energy requirements.
Energybasis refers to the quantities of nutrients per animal’s
energyrequirement. Units of measure are typicallynutrient
amounts per 100 kcal or 1 MJ metabolizable energy (ME).
Occasionallyan animal’sprotein, fatand digestible (soluble) carbo-
hydrate needs are expressed as a percentage of the animal’s total
energy needs (Table 4).
Absolute basis refers to the unit measure (usually weight) of a
nutrient that is needed by an animal in a 24-hour period. These
needs are expressed as quantities per kg of body weight per day.
FOOD’S NUTRIENT CONTENT
Although there are three methods for expressing an animal’s nutri-
ent needs, there are four methods for expressing a food’s nutrient
content: 1) as fed basis, 2) drymatter basis, 3) dry matter basis,
energy density defined and 4) energy basis.
As fed basis simply refers to the quantity of nutrients in a food
as it is fed. This method ignores moisture and energy content. The
units of measure are percentages or quantities of nutrients per unit
weight (kg) of food.
Dry matter is that weight of the food remaining after the water
content has been subtracted from the as fed amount. Dry matter
basis, therefore, is the amount of nutrients in the food’s dry mat-
ter. It accounts for variability in water content but not variability in
energy density.The units of measure are percentages or quantities
of nutrients per unit weight (kg) of food dry matter. The usefulness
of dry matter basis is limited because the energy density of indi-
vidual foods can vary widely. This consideration will be further
explained below (drymatter basis, energy density defined). Tables
2and 3show the conversion from as fed basis to drymatter basis.
Dry matter basis, energy density defined is the same as dry mat-
ter but specifies a food’s energy density, thus accounting for
potential variability. The units of measure are the same as those
used with dry matter basis but are further qualified by expressing
the energy density of the food. For example, recommended nutri-
ent values for canine and feline foods are based on an energy den-
sity of 3.5 and 4.0 kcal ME/g (14.64 and 16.74 kJ ME/g) of food
dry matter, respectively. Dry matter basis, energy density defined is
probably the most widely used method of expressing a food’s
nutrient content.
Energy basis refers simply to the amount of nutrients per 100
kcal or 1 megajoule ME of food. Occasionally, a food’s protein, fat
and digestible carbohydrate content is expressed as a percentage
of the food’s total energy content (Table 4).
Both dry matter basis, energy density defined and energy basis
are reasonably accurate methods of expressing a food’s nutrient
content. However, even these methods have limitations.
Animals require less food to meet their energy requirements
when foods with higher energy densities are fed. Under these cir-
cumstances, the concentrations of the other nutrients in the food
need to be increased proportionately,to ensure the animal receives
the minimum amount of all nutrients needed in a smaller amount
of food.
When foods with lower energy densities are fed, a lower con-
centration of the other nutrients may be required, assuming the
dog or cat could eat, or would be fed, enough of the food to meet
its energyrequirement. In these instances, the nutrient levels need
to be decreased proportionately, so that the animal would not
receive toxic levels of nutrients in a larger amount of food.
Foods of low energydensity, particularlythose low in fatand
high in fiber, are usually intended for animals that have a tenden-
cy to be overweight. These animals should be fed fewer calories
than animals with normal body weights and body condition scores.
The nutrient content of foods in this category should not be cor-
rected for their lower energydensity. During weight loss, there is a
disproportionately lower energy intake relative to the non-energy
nutrients. Although these animals require fewer calories to lose
weight, as far as is known, their requirement for other nutrients has
not changed. Thus,they are essentially being fed the same amount
of drymatter but fewer calories. On an energybasis (g/kcal), the
food’s nutrient values will be higher than if the animal had normal
energy requirements.
On the other end of the spectrum are situations in which foods
of high energy density are fed to animals with an unusually high
need for energy-providing nutrients relative to non-energy nutri-
ents. A working sled dog is an example. In this case, on an energy
basis, the food’s non-energy nutrient content could be lower than
if the animal had normal energy needs.
CONVERTING TO SAME UNITS
Comparing food on an as fed basis to an animal’s requirement on
an absolute basis requires: 1) mathematical calculation and 2)
either the energy density of the food or the amounts of the ener-
gy-supplying nutrients in the food. Table 5 provides an example of
such a calculation.
When using dry matter basis, energy density defined to compare
foods or to compare foods with animal requirements, the energy
densities must be the same for the comparisons to be meaningful.
Table 6 shows how to convert to the same energy density. In some
cases it will be desirable to convert food nutrient content on an as
fed basis to dry matter basis, energy density defined (Case 1-1).
Box 1-2. Typical Methods and Units for Expressing a Patient’s Nutrient Needs and a
Food’s Nutrient Content and Methods for Conversion to the Same Units.
11
An Iterative Process
Table 1. Comparisons of methods to express food nutrient con-
tent and animal requirements/allowances for nutritional assess-
ment of food.
Food nutrient content (units)
As fed basis (% or amount of nutrient/kg food)
Dry matter basis (% or amount of nutrient/kg of food dry matter)
Dry matter basis, energy density defined (% or amount of nutri-
ent/kg of food dry matter, at a specified energy density)
Energy basis (amount of nutrient/100 kcal or 1 megajoule ME of
food’s energy content)
Dog/cat requirements/allowances (units)
Absolute basis (amount of nutrient/kg animal)
Dry matter basis, energy density defined (% or amount of nutri-
ent/kg of food dry matter, at a specified energy density)
Energy basis (amount of nutrient/100 kcal or 1 megajoule ME of
animal’s energy requirement)
Table 2. How to convert from as fed basis to dry matter basis.
Step 1. Obtain the food’s dry matter content by subtracting the
water content from the as fed amount of the food.
Example A: If a moist food contains 75% water, 25% of the
food is dry matter:
100% as fed – 75% water = 25% food dry matter
Example B: If a dry food contains 10% water,90% of the
food is dry matter:
100% as fed – 10% water = 90% food dry matter
Step 2. Convert the percentage as fed nutrient content of the
food to a dry matter basis by dividing the percentage of the nutri-
ent content on an as fed basis by the percentage dry matter.
Example A: If the moist food above contained 10% protein
on an as fed basis, on a dry matter basis it would contain
40% protein:
10% protein as fed basis ÷ 25% dry matter = 40%
protein dry matter basis
Example B: If the dry food above contained 18% protein on
an as fed basis, on a dry matter basis, it would contain 20%
protein:
18% protein as fed basis ÷90% dry matter = 20%
protein dry matter basis
Table 3. Shorthand method for converting from as fed basis to dry
matter basis.
Aless accurate, shorthand method for converting from an as fed
basis to a dry matter basis is to simply multiply the percentage
nutrient content on an as fed basis by four for moist foods or add
10% for dry foods. This method is based on the assumption that
moist foods contain approximately 75% water and dry foods con-
tain approximately 10% water.Check the guaranteed analysis on
the product label.
Example A: If a moist food contains 10% protein on an as
fed basis, on a dry matter basis it would contain 40% pro-
tein:
10% protein as fed basis x 4 (factor for moist foods) =
40% protein dry matter basis*
Example B: If a dry food contains 18% protein on an as fed
basis, on a dry matter basis it would contain 20% protein:
18% protein as fed basis + 10% (factor for dry food) =
approximately 20% protein dry matter basis*
*Compare these results with those obtained in Table 2 for moist
and dry foods with the same moisture content.
Table 4. How to determine the protein, fat and carbohydrate
content as a percent of the food’s total energy content.
Practically speaking, the available energy in foods for dogs and
cats is provided by digestible carbohydrates, protein and fat;
dietary fiber provides little if any energy to these species.
Occasionally an animal’s need for, or a food’s content of, any or all
of these three nutrients is expressed in terms of the fraction of the
total energy they provide. The method is simply another way to
express the relative amounts of these three nutrients. The follow-
ing example demonstrates how to calculate the percentage of kcal
and kJ from protein, fat and digestible carbohydrate of a pet food.
kcal/g of kJ/g of kcal/g of kJ/g of
Nutrient % nutrient nutrient food** food**
Protein 22 3.5*14.64* 0.77 3.22
Fat 9 8.5*35.56* 0.77 3.20
Digestible
carbohydrate 51 3.5*14.64*1.79 7.47
Total - - - 3.33 13.89
%kcal from protein = 0.77 ÷ 3.33 = 23.1
%kJ from protein = 3.22 ÷ 13.89 = 23.2
%kcal from fat = 0.77 ÷ 3.33 = 23.1
%kJ from fat = 3.20 ÷ 13.89 = 23.0
%kcal from digestible carbohydrate = 1.79 ÷ 3.33 = 53.8
%kJ from digestible carbohydrate = 7.47 ÷ 13.89 = 53.8
*Modified” Atwater values.
**See Box 1-6, Table 3 for a more detailed explanation for
calculation of energy density of pet foods.
Table 5. Example illustrating the mathematical process required to
compare a food’snutrient content on an as fed basis to an ani-
mal’sneeds on an absolute basis.
Example: If an intact male cat weighing 4.5 kg requires 31 mg of
magnesium (Mg) per day (recommended allowance) and the cat’s
food as fed contains 0.12% Mg, 20% fat, 35% protein and 27%
digestible carbohydrate, does the cat receive adequate amounts
of Mg? The answer is calculated as follows:
1) First find out how much food is to be fed. Because animals are
fed to meet their energy requirements, the first step is to deter-
mine the energy density of the food, if it is unknown. This is
done by calculating the amount of energy provided by each of
the energy-supplying nutrients. Using the “modified” Atwater
energy values of 3.5, 8.5 and 3.5 kcal metabolizable energy
(ME)/g (14.64, 35.56 and 14.64 kJ ME/g) for protein, fat and
digestible carbohydrate respectively (See Box 1-6,Table 2),
multiply the percentage of each nutrient in the food (as fed
basis) by 1 g of food. Then multiply the answer by the energy
density of each nutrient. The sum of the three separate energy
values is the energy density of the food.
In kcal ME/g of food:
35% protein x 1 g food x 3.5 kcal ME/g
=1.23 kcal ME/g from protein
20% fat x 1 g food x 8.5 kcal ME/g
=1.70 kcal ME/g from fat
27% digestible carbohydrate x 1 g food x 3.5 kcal ME/g
=0.95 kcal ME/g from carbohydrate
Sum
3.88 kcal ME/g food (total)
Box 1-2 continued
better, as owners increase the proportion of new food and
decrease the proportion of old food (Table 1-1). Nearly all pets
readily tolerate a seven-day transition period. A much longer
transitional period is recommended in cases in which the food
change is known to be significant, the pet has demonstrated a
poor tolerance to such changes in the past or food refusal is
expected (Table 1-1). For example,a long transition schedule is
likely to be needed for an old cat recently diagnosed with kid-
ney disease when the food must be switched from a highly
palatable grocery “gourmet” food to an appropriate veterinary
therapeutic food.
Simple Mathematical Ration Balancing
(Pearson Square)
The Pearson square is another useful diet balancing tool.This
handy method can be used to combine any two foods, supple-
ments or ingredients to yield a mixture with a desired nutri-
ent content. Figure 1-4 shows how the Pearson square
method is used to balance a diet. Here’s how to use the
Pearson square:
Asmall square is drawn and the desired nutrient concentra-
tion of the proposed mixture is written in the middle of the
square.
The nutrient concentration of one component of the mix-
ture is written at the upper left corner of the square.
The nutrient concentration of the other component of the
mixture is written at the lower left corner of the square.
The nutrient values at the corners are subtracted from those
in the center of the square. The smaller number is always
subtracted from the larger and the differences written diag-
onally at the right corners of the square.
The differences are added together and the sum is written
below each difference as the denominator of a fraction.
The fractions are converted to percentages. These percent-
ages are the proportion of each component of the mixture in
the corners directly to the left. When combined in those
percentages, the constituent components will yield a mixture
Small Animal Clinical Nutrition
12
2) The next step is to determine the daily energy requirement
(DER) of the animal. Multiply the formula for resting energy
requirement (RER) by the appropriate modifier for mainte-
nance of an adult cat (Box 6, Table 1).
RER (kcal ME/day) = 70(BWkg)0.75
RER (kJ ME/day) = 293(BWkg)0.75
=70(4.5 BWkg)0.75 =216 kcal ME/day
=293(4.5 BWkg)0.75 =904 kJ ME/day
Modifier for feline adult maintenance = 1.4 x RER = DER
Modifier for feline adult maintenance = 1.4 x RER = DER
DER (kcal ME/day) = 1.4 x 216 kcal ME = 302 kcal ME
DER (kJ ME/day) = 1.4 x 904 kJ ME = 1,266 kJ ME
3) Determine the amount of food to be fed by dividing the cat’s
energy requirement by the energy density of the food.
302 kcal ME/day ÷3.88 kcal ME/g = 78 g food/day
1,266 kJ ME/day ÷16.18 kJ ME/g = 78 g food/day
4) Determine the amount of Mg provided by the food by multi-
plying the amount of food fed by the percentage of Mg in the
food.
78 g food x 0.12% Mg = 0.090 g (90 mg) Mg
The amount of Mg provided by the food (90 mg) compared with
the animal’s requirement of 31 mg indicates more than an ade-
quate (threefold) amount of Mg.
Table 6. How to convert to the same energy density.
Correcting energy densities in order to make valid nutrient com-
parisons, either between foods or between a food and an ani-
mal’s requirement, is based on the assumption that the relation-
ship between nutrient content and energy density is directly pro-
portional. A simple ratio can be established to generate a multi-
plier that converts the units of the animal’s requirements to those
of the food; then the animal’s requirement and the food’s nutrient
content can be compared. The multiplier is obtained by dividing
the energy density of the food by the requirement energy density.
Example: Is a food that provides 0.72% potassium and 4 kcal
(16.74 kJ)/g, on a dry matter (DM) basis, adequate for canine
adult maintenance?
1) The requirement for potassium is 0.6% DM basis in an adult
dog food that provides 3.5 kcal (14.64 kJ)/g.
2) Convert the requirement to the same energy density as the
food by generating the multiplier.
Multiplier
=Food energy density ÷ requirement energy density
=4.0 kcal (16.74 kJ)/g DM ÷ 3.5 kcal (14.64 kJ)/g DM
=1.14
3) To obtain the equivalent nutrient requirement for a food pro-
viding 4 kcal (14.74 kJ)/g, on a DM basis, multiply the require-
ment by the multiplier.
Equivalent nutrient requirement
=1.14 x 0.06% potassium
=0.68% potassium, 4 kcal (14.74 kJ)/g, on a DM basis
4) The amount of potassium in the food (0.72%) is compared to
the animal’s equivalent nutrient requirement (0.68%) and is
found to be adequate.
5) The multiplier obtained above (1.14) can be used to convert
the other nutrient requirements to the same basis as the food
to compare the adequacy of their levels, if desired.
After the energy densities of the food and the animal’sneeds are
converted to the same units, the comparison is simple.
Box 1-2 continued
Table 1-1. Recommended short- and long-term food transition
schedules for dogs and cats.
Short schedule* Long schedule** Food percentages
Dogs and Dogs Cats Previous New
cats (days) (days) (weeks) food food
1,2 1-3 1 75 25
3,4 4-6 2 50 50
5,6 7-9 3 25 75
710 4 0 100
*Recommended for most healthy dogs and cats.
**Recommended for situations in which the food change is
known to be significant, the dog or cat has demonstrated
low tolerance to such changes in the past or food refusal
is anticipated.
13
An Iterative Process
The nutrient content of a food can be determined one of four ways:
1) Obtain the target values from the manufacturers of commercially
prepared foods.
2) Order a laboratory analysis.
3) Calculate the content based on the published values for the ingre-
dients.
4) Use the information found in the label guaranteed analysis and typ-
ical analysis (Chapter 9).
Only the first three are recommended because of the severe limita-
tions of label guarantees and typical analyses.
Most pet food manufacturers, upon request, will supply target val-
ues for the nutrient content of their products. This approach is simple
and inexpensive. Although these values usually reflect actual average
nutrient levels, occasionally they vary significantly from actual values,
thus this method is not always accurate. No laws govern the accura-
cy of target nutrient levels. In most instances, however, these values
will be adequate.
The basic laboratory analysis is the proximate analysis (Figure 5-
3), which provides the percentage moisture, crude protein, crude
fat, ash and crude fiber in a food and allows calculation of the
digestible carbohydrate fraction (also referred to as the nitrogen-
free extract [NFE]). Most commercial laboratories will also conduct
more expansive nutrient analyses including amino acids, fatty acids,
minerals, vitamins and various fiber fractions.Analysis of food sam-
ples for nutrient content is very straightforward and usually accu-
rate. Limitations include proper sampling, the potential issue of
analytical variance for certain nutrients and the expense and time
involved for a complete analysis.
Calculations require nutrient contents of ingredients and a formula
for the food in question. Published average nutrient contents of ingre-
dients can be obtained from NRC nutrient requirement booklets and
listings of average nutrient contents of human foods. This approach
would likely be used for determining the nutrient content of a home-
made food. One limitation of this method is the time and knowledge
required to do such calculations. Another limitation is accuracy (i.e.,
how closely the published average nutrient content of the ingredients
represents the ingredient’s actual nutrient content). Values can vary
markedly.
The use of guaranteed analyses (United States and Canada) or typ-
ical analyses (Europe) listed on the label of commercially prepared
foods as a means of establishing nutrient content has severe limita-
tions:
In the case of guaranteed analysis, the quantities listed are mini-
mums or maximums only.
It is only necessary to list a fraction of the nutrients in the food (e.g.,
guaranteed analysis only requires crude protein, crude fat, crude fiber
and moisture; typical analysis only requires crude protein, crude fat,
crude fiber, ash and moisture if more than 14%).
Guaranteed analysis values are not the nutrient content of the food.
They are a guarantee by the manufacturer that the food contains not
more, or less, than the stated amount. Label guarantees can provide
ageneral idea of the nutrient content for a limited number of nutrients
and the classification of the food (growth-type food, maintenance food,
etc.).
Use caution when using guaranteed and typical analyses to com-
pare specific nutrient levels between foods. When such comparisons
are made, be sure to compare similar forms of foods (i.e., dry to dry
or moist to moist). Label guarantees are listed on an as fed basis.
Different forms of food can be compared if the foods are converted to
the same moisture or energycontent (Tables 2, 3 and 6in Box 1-2).
There are two categories of food evaluation/balancing software programs listed below. The category entitled “Veterinary Clinical Nutrition
Software” is a special application designed for use by veterinarians and veterinary nutritionists. It contains commercial pet food and human
food nutrient data thatenable users to select foods and make feeding and weight-loss feeding plans for individual patients. Additional tools
for automatic formulation of homemade pet foods from recipes are also available.
Acautionary reminder: software programs are tools intended to make the mathematical work of food evaluation/balancing/formulation
easier and faster. Their accuracy depends entirely on the accuracy of the databases from which they are working and they do not account
for nutrient availability regarding ingredient sourcing and cooking, nor do they ensure a palatable food.
Veterinary Clinical Nutrition
Software Programs
Davis Veterinary Medical
Consulting, PC
707 Fourth Street, Suite 307
Davis, CA 95616
Phone: (530) 756- 3862 or
(888) 346-6362
Fax: (530) 756-3863
E-mail:
info@dvmconsulting.com
www.balanceit.com
Balance IT
Commercial Formulation
Software Programs
Creative Formulation
Concepts, LLC
1831 Forest Drive, Suite H
Annapolis, MD 21401
Phone: (410) 267-5540
Fax: (410) 267-5542)
http://creativeformulation.com
Concept5
Feedsoft Formulation
14001 Dallas Parkway,
Suite 1200
Dallas, TX 75240
Phone: (866) 363-7843
Fax: (972) 231-9096
http://feedsoft.com
Agricultural Software
Consultants, Inc.
2726-600 Shelter Island Drive
San Diego, CA 92106
Phone: (619) 226-2600
Fax: (619) 226-7900
Mixit-Win 5
FormatInternational, Ltd.
FormatHouse
Poole Road
Woking
Surrey England GU21 6DY
Phone: +44 (0)1483 726081
Fax: +44 (0)1483 722827
www.format-international.com
New Century
Format International, Inc.
10715 Kahlmeyer Drive
St. Louis, MO 63132
Phone: (888) 628-5683
Fax: (314) 428-4102
www.format-international.com
New Century
Box 1-3. Four Ways to Determine the Nutrient Content of a Food.
Box 1-4. Computerized Food Evaluation/Balancing Programs.
having the same concentration as the number in the center
of the square.
Feeding Tests and Clinical Trials
Evaluationof the product label of commercial foods can pro-
vide feeding test information. Determining if a food has been
evaluated in clinical trials is a more complicated matter and is
covered in Chapter 9 and in various clinical chapters.
Whether or not commercial foods for healthy pets have been
animal tested can usually be determined from the nutritional
adequacy statement on the product’s label (Chapter 9).
Published clinical trials and case reports for commercial veteri-
nary therapeutic foods can be obtained from the products
manufacturer. As mentioned above, manufacturers’ addresses
and toll-free phone numbers are found on pet food labels.
However, some brands of these products have passed regulato-
ryagency (AAFCO) prescribed feeding tests although the
product label may not include such information.
Commercial pet foods that have undergone AAFCO-pre-
scribed or similar feeding tests provide reasonable assurance of
nutrient availability and sufficient palatability to ensure
acceptability (i.e., food intake sufficient to meet nutrient
needs). Feeding tests also provide some assurance that a prod-
uct will adequately support certain functions such as gestation,
lactation and growth. However, even controlled animal testing
is not infallible.
In the United States, the AAFCO testing protocol for adult
maintenance lasts six months, requires only eight animals per
group and monitors a limited number of parameters (Chapter
9). Passing such tests does not ensure the food will be effec-
tive in preventing long-term nutrition/health problems or
detect problems with prevalence rates less than 15%.
Likewise, these protocols are not intended to ensure optimal
growth or maximize physical activity. Besides feeding tests,
AAFCOprescribes other methods to assurenutritional ade-
quacy(Chapter 9). Thus, in addition to meeting AAFCO
requirements, the food should be evaluated to ensurethat key
nutritional factors areat levels appropriate for promotion of
long-term health or for optimal performance. Few, if any,
homemade recipes havebeen animal tested according to pre-
scribed feeding protocols.
Although not considered feeding tests, the personal observa-
tions of veterinarians and pet owners about the performance of
specific foods or recipes can be valuable. Such experiences are,
in a sense, uncontrolled feeding tests.Through experience, vet-
erinarians and pet owners form impressions about a food’s value
in disease management, its ability to support various lifestages
and work, its palatability, resultant stool quality and skin and
coat benefits. Limitations of personal observations include the
lack of controls and the length of time it takes (months to years)
to gather sufficient information about a wide variety of prod-
ucts. Also, some commercial products are continuously
improved; therefore, yesterday’s product does not necessarily
reflect the capabilities of the “same” product today. However,
personal observations can augment controlled feeding tests
such as published clinical trials and regulatory agency pre-
scribed feeding protocols for healthy pets.
Physical Evaluation of the Food
Conducting a physical evaluation of the food is of limited use-
fulness. It can provide information about a food’s consistency
and whether or not there are extraneous materials in the food.
It can also determine package quality, which may or may not
reflect product quality. Physical evaluation of the food is prob-
ably most useful for assessing whether or not the food has
spoiled (Chapter 11).
Small Animal Clinical Nutrition
14
As an example, the Pearson squarecan be used to solve the
following problem: How much calcium carbonate containing
36% calcium must be added to a meat-based food to increase
its calcium content from 0.01% to 0.3% on an as fed basis?
Assume you aremaking 5 kg of the mixture. The problem is set
up and worked as follows:
The final step converts fraction to percentages by dividing the
numerator of the fractions by the denominator and multiplying
by 100.
Meat-based food: (35.70 ÷ 35.99) x 100 = 99.19%
Calcium carbonate: (0.29 ÷ 35.99) x 100 = 0.81%
If the total mixture is 5 kg, then 99.19% (4.96 kg) should be
ameat-based food and 0.81% (0.04 kg, or 40 g) should be
calcium carbonate.
%calcium in
calcium carbonate
=36.0
%calcium in
meat-based food
=0.01
36.0 – 0.3 = 35.70
+
0.30 – 0.01 = 0.29
35.99
Figure 1-4. Example of how to use the Pearson square.
%calcium
required = 0.3
It is not the intention of this book to teach complete food for-
mulation or extensive food balancing. Few practitioners
need to know how to formulate balanced foods from
scratch. Nutrient requirement information is readily avail-
able; however, accurate/relevant ingredient nutrient data-
bases, an understanding of the availability of nutrients in
various ingredients, knowledge of the effect of cooking on
nutrient availability and knowledge of all of these variables
on palatability are complex issues. Such information is not
readily available, and usually requires assimilation by a team
of experts, including veterinarians, nutritionists and food sci-
entists to ensure proper formulation of complete and bal-
anced foods.
Fortunately, numerous complete pet food options are
readily available from commercial pet food manufacturers.
Many homemade food recipes have also been published. Be
sure to obtain homemade food recipes from reliable sources
as discussed in Chapter 10.
Box 1-5. Food Formulation and
Extensive Food Balancing.
15
An Iterative Process
Calculations to estimate food dosage are based on the assumption
that if a food contains the proper proportions of nutrients relative to
its energy density, and is fed to meet an animal’s energy require-
ment, then the animal’s requirements for non-energy nutrients will
automatically be met. This calculation has three steps:
1) Estimate the energy requirement of the animal (Table 1).
2) Determine the energy density of the food (kcal or kJ ME/g food,
as fed basis). Sources include product labels, product literature,
contacting the product’s customer service department by phone
or e-mail (phone numbers or e-mail addresses can often be
found on the product label). The energy density can be calculat-
ed using Atwater values (Tables 2 and 3).
3) Divide the energy requirement of the patient by the energy den-
sity of the food to determine the daily amount to feed (food
dosage).
Table 1. Calculation of energy requirements.
Calculation of daily energy requirement (DER) is based on the rest-
ing energy requirement (RER) for the animal modified by a factor to
account for normal activity or production (e.g., growth, gestation,
lactation, work). RER is a function of metabolic body size. RER is
calculated by raising the animal’sbody weight in kg to the 0.75
power.The average RER for mammals is about 70 kcal/day/kg
metabolic body size: RER (kcal/day) = 70(BWkg)0.75 or 30(BWkg) +
70 (if the animal weighs between 2 and 45 kg). RER values can
also be obtained from Table 5-2, Part 3. Expressed in kJ, the aver-
age RER for mammals is about 293(BWkg)0.75.These energy
requirements should be used as guidelines, starting points or esti-
mates of energy requirements for individual animals and not as
absolute requirements.
Feline DER
Maintenance (0.8 to 1.8 x RER)
Neutered adult = 1.2-1.4 x RER
Intact adult = 1.4-1.6 x RER
Inactive/obese prone = 1.0 x RER
Weight loss = 0.8 x RER
Senior adult (7-11 years) = 1.1-1.4 x RER
Very old adult (>11 years) = 1.1-1.6 x RER
Critical care = 1.0 x RER
Weight gain = 1.2-1.8 x RER at ideal weight
Gestation
Energy requirement increases linearly during gestation in cats.
Energy intake should be increased to 1.6 x RER at breeding and
gradually increased through gestation to 2 x RER at parturition.
Free-choice feeding of pregnant queens is also recommended.
Lactation
Lactation is nutritionally demanding and the physiologic and nutri-
tional equivalent of heavy work. Recommend 2 to 6 x RER
(depending on number of kittens nursing) or free-choice feeding.
The following table may also be used to estimate the DER of lac-
tating queens:
Weeks of lactation DER
Weeks 1-2 RER + 30% per kitten
Week 3 RER + 45% per kitten
Week 4 RER + 55% per kitten
Week 5 RER + 65% per kitten
Week 6 RER + 90% per kitten
Growth
Daily energy intake for growing kittens should be about 2.5 x RER.
Free-choice feeding is recommended.
Canine DER
Maintenance (1.0 to 1.8 x RER)
Neutered adult = 1.6 x RER
Intact adult = 1.8 x RER
Inactive/obese prone = 1.2-1.4 x RER
Weight loss = 1.0 x RER
Critical care = 1.0 x RER
Weight gain = 1.2-1.8 x RER at ideal weight
Work
Light work = 1.6-2.0 x RER
Moderate work = 2.0-5.0 x RER
Heavy work = 5.0-11.0 x RER
Gestation
First 42 days: feed as an intact adult.
Last 21 days: use 3 x RER. (This quantity may need to be
increased to maintain normal body condition for some dogs, espe-
cially larger breeds.)
Lactation
Lactation is nutritionally demanding and the physiologic and nutri-
tional equivalent of heavy work.
Recommend 4 to 8 x RER (depending on number of puppies nurs-
ing) or free-choice feeding.
The following table may also be used to estimate the DER of lac-
tating bitches:
Puppies (No.) DER
13.0 x RER
23.5 x RER
3-4 4.0 x RER
5-6 5.0 x RER
7-8 5.5 x RER
96.0 x RER
Growth
Daily energy intake for growing puppies should be 3 x RER from
weaning until four months of age.
At four months of age energy intake should be reduced to 2 x RER
until the puppy reaches adult size.
Table 2. Energy available from protein, fat and digestible carbohy-
drate (nitrogen-free extract).
Metabolizable energy (kcal/g)
Digestible
Species Crude protein Crude fat carbohydrate
All*4.4 x digest.*9.4 x digest.*4.15 x digest.*
Dogs
and cats** 3.5** 8.5** 3.5**
Metabolizable energy (kJ/g)
Digestible
Species Crude protein Crude fat carbohydrate
All*18.41 x digest.*39.33 x digest.*17.36 x digest.*
Dogs
and cats** 14.64** 35.56** 14.64**
Key: digest. = digestibility
*The most accurate value to use when the digestibility of the three
nutrients is known. (Adapted from Lewis et al, 1987)
**“Modified” Atwater values (Dog Food Nutrient Profiles and Cat
Food Nutrient Profiles). Association of American Feed Control
Officials 2007.
Box 1-6. A Method for Calculating the Food Dosage Estimate.
Label Evaluation
The ingredient panel of the pet food label provides general
information about which ingredients were used and their rela-
tive amounts. The ingredients used in the product are listed in
descending order by weight in many countries. The ingredient
panel can be useful if specific ingredients are contraindicated
for certain animals or an owner has an ingredient concern.
However, the quality of the ingredients cannot be determined
from the label and there is much misinformation and, as a
result, misunderstandings about pet food ingredients (Chapter
8). As mentioned above, the presence or absence of specific
protein sources or other ingredients in a food can be obtained
from the product label.
Depending on the country, product labels will also provide
information that indicates by what means the product has been
shown to be nutritionally adequate (Chapter 9).
Assess and Determine the Feeding Method
Feeding methods relate directly to the physiologic or disease
state of the animal and the food or foods being fed. Thus, the
information obtained by assessing the animal and the food is
fundamental to assessing the feeding method. There are at
least three things to consider regarding feeding methods: 1)
feeding route, 2) amount fed and 3) how the food is offered
(when, where, by whom and how often). In addition, feeding
factors that affect compliance should be considered, such as
whether or not the animal has access to other foods and who
provides the food.
Feeding Route
Whether or not the feeding route is appropriate depends on
the animal’s condition.Although most animals are able to feed
themselves, orphans and some critical care patients may
require assistance. Assisted-feeding methods are described in
detail in Chapters 25 and 26. Assisted-feeding methods
include enteral feeding by syringe or tube (several approaches)
and parenteral feeding.
Amount Fed
The nutrient needs of an animal are met by a combination of
the nutrient levels in the food and the amount of food offered
and eaten. Even if a food has an appropriate nutrient profile,
significant over- or undernutrition could result if too much or
too little is consumed. Thus, it is important to know if the
amount being consumed is appropriate.
The amount of food offered should be determined when
taking the patient’s history. Although many animals are fed
free choice, owners should still be able to provide a reasonable
estimate of the actual amount being consumed. The owner
may need to return home and measure the amount the pet
consumes to provide an accurate report or estimate the amount
based on the purchasing frequency of bags or cans. The
amount actually being consumed can then be compared with
the amount that should be fed. If the animal in question has a
normal BCS (3/5) and no history of weight changes, the
amount fed is probably appropriate. Exceptions to this gener-
alization include growing animals, animals that are gestating
or lactating and hunting dogs and other canine athletes early
in the athletic event season.
The appropriate amount to feed can be difficult to determine
precisely, but can be estimated. For most commercial pet foods,
food dosage estimates can be found in the feeding guidelines on
the product label. However, food dosages can be calculated if
guidelines are unavailable. The precision of feeding guidelines
or calculated food dosages is limited because the efficiency of
food use varies among individuals because of differences in
physical activity,metabolism, body condition, insulative charac-
Small Animal Clinical Nutrition
16
Table 3. Example calculation of caloric density of a pet food.*
Analysis Metabolizable energy (kcal)
kcal/g kcal/g
% of nutrient** of food
Protein 22 x 3.5 = 0.77
Fat 9 x 8.5 = 0.77
Fiber*** 3 x 0 = 0
Moisture 10 x 0 = 0
Ash*** 5 x 0 = 0
Digestible
carbohydrate51 x 3.5 = 1.79
Total 3.32††
Analysis Metabolizable energy (kJ)
kJ/g kJ/g
%of nutrient** of food
Protein 22 x 14.64 = 3.22
Fat 9 x 35.56 = 3.20
Fiber*** 3x0 = 0
Moisture 10 x 0 = 0
Ash*** 5x0 = 0
Digestible
carbohydrate51 x 14.64 = 7.47
Total 13.89††
3.33 kcal/g (13.89 kJ/g) x amount of food/measuring cup
=kcal/measuring cup†††
*As fed basis.
**From Table 1-8.
***If not available, these may be estimated as 3% fiber and
9% ash in dry foods, 1% fiber and 6% ash in soft-moist
foods and 1% fiber and 2.5% ash in moist foods.
Percent digestible carbohydrate (nitrogen-free extract)
usually is not stated but can be calculated on an as fed
basis by subtracting the percent protein, fat, fiber,mois-
tureand ash from 100.
††If the nutrient percentages were obtained from the label
guarantee, multiply the food’s caloric density by 1.2 for
moist pet foods and 1.1 for semi-moist and dry pet foods.
In this example, 3.33 (13.89 kJ) x 1.1 = 3.66 kcal (15.28
kJ)/g of dry food.
†††An 8-oz. (volume) measuring cup holds 3 to 3.5 oz. by
weight (85 to 100 g) of most dry pet foods or 3.5 to 5 oz.
by weight (100 to 150 g) of most semi-moist pet foods. It
is more accurate to use the average weight of three indi-
vidual measuring cups of food in determining kcal or
kJ/cup.
Box 1-6 continued
teristics of the coat and external environment. Even when envi-
ronmental conditions and physical activity are similar, sizable
individual differences can exist.
Figure 1-5 contains data generated from several controlled
studies about the amount of food (energy content standardized)
consumed by mature, non-reproducing dogs and cats kept in
kennels or runs under similar environmental conditions while
maintaining body weight. The total amount of energy needed
by dogs and cats for maintenance, even under similar environ-
mental conditions can vary two- to threefold. Even when the
extremes are excluded (the top and bottom 2.5%), the amount
of energy needed varied more than twofold (Lewis et al, 1987).
Therefore, a commercial products amount to feed guideline or
acalculated food dosage should only be considered an estimate
or a starting point that may very likely need adjustment.
Calculations to estimate food dosage are based on the
assumption that if a food contains the proper proportions of
nutrients relative to its energy density,and is fed to meet an ani-
mal’s energy requirement, then the animal’s requirements for
non-energy nutrients will be met automatically. This is an
important concept. Box1-6 demonstrates the method for cal-
culating food dosage estimates. Case 1-2 includes an example
of a food dosage problem.
How the Food is Offered
The amount fed is usually offered in one of three ways: 1) free-
choice feeding (dogs and cats), 2) food-restricted meal feeding
(dogs and cats) and 3) time-restricted meal feeding (dogs).
The number of feedings per day must be considered when the
last two methods areused.
Free-choice feeding (also referred to as ad libitum or self
feeding) is a method in which more food than the dog or cat
willconsume is always available; therefore,the animal can eat as
much as it wants, whenever it chooses.The major advantage of
free-choice feeding is that it is quick and easy. All that is nec-
essary is to ensure that reasonably fresh food is always available.
Free-choice feeding is the method of choice during lactation.
Free-choice feeding also has a quieting effect in a kennel and
timid dogs have a better chance of getting their share if dogs are
fed in a group.
Disadvantages include: 1) anorectic animals may not be
noticed for several days, especially if two or more animals are
fed together, 2) if food is always available, some dogs and cats
will continuously overeat and may become obese (such animals
should be meal fed) and 3) moist foods and moistened dry
foods left at room temperature for prolonged periods can spoil
and are inappropriate for free-choice feeding (Chapter 11).
When changing a dog from meal feeding to free-choice
feeding, first feed it the amount of the food it is used to receiv-
ing at a meal. After this food has been consumed and the dog’s
appetite has been somewhat satisfied, set out the food to be fed
free choice. This transitioning method helps prevent engorge-
ment by dogs unaccustomed to free-choice feeding.
Engorgement is generally not a problem when transitioning
cats to free-choice feeding. Although dogs and cats unaccus-
tomed to free-choice feeding may overeat initially, they gener-
ally stop doing so within a few days, after they learn that food
is always available. Avoid taking the food away at any time
during this transition period. Each time food is taken away
increases the difficulty in changing the animals to a free-choice
feeding regimen.
With food-restricted meal feeding, the dog or cat is given a
specific, but lesser,amount of food than it would eat if the
amount offered werenot restricted (i.e., free choice). Time-
restricted meal feeding is a method in which the animal is given
morefood than it willconsume within a specified period of
time,generallyfive to 15 minutes. Time-restricted meal feed-
ing is of limited usefulness with dogs and has little if any prac-
tical application in cats. Many dogs can eat an entire meal in
less than two minutes. Both types of meal feeding are repeated
at a specific frequency such as one or more times a day. Some
people combine feeding methods, such as free-choice feeding a
17
An Iterative Process
Figure1-5. Variation in expected energy intake required to maintain optimal body weight in dogs and cats. Data were collected from 120 dogs
and 76 cats kept under similar conditions and fed the amount of a variety of commercial pet foods necessary to maintain body weight
(Adapted from Lewis et al, 1987).
dry or semi-moist food and meal feeding a moist food or other
foods such as meat or table scraps.
Food consumption resulting from frequent meal and free-
choice feeding has several advantages. Small meals fed fre-
quently throughout the day result in a greater loss of energy
due to an increase in daily meal-induced heat production.
Also, providing frequent small meals generally result in greater
total food intake than does less frequent feeding (Mugford and
Thorne, 1980). Frequent feeding of small meals benefits ani-
mals with dysfunctional ingestion, digestion, absorption or use
of nutrients.
Frequent feeding is also desirable in normal animals that
require a high food intake. Puppies and kittens less than six
months old, some dogs engaged in heavy work (high levels of
physical activity), dogs and cats experiencing ambient temper-
ature extremes, bitches and queens during the last month of
gestation and during lactation should be fed at least three
times per day to ensure that their nutritional needs are met.
These animals may require one and one-half to four times as
much food per unit of body weight than most normal adult
dogs and cats. A reduced frequency might limit total food
intake in these situations. Also, more frequent feeding during
periods of variable appetite suppression, such as occurs with
psychologic stress or high ambient temperatures, helps ensure
adequate food intake.
Most clinically normal adult dogs that are not lactating,
working or experiencing stress willhave a sufficient appetite
and physical capacity to consume all of the food required daily
in a single 10-minute period (assuming food of typical nutrient
density[about 3.5 kcal/g or 14.64 kJ/g drymatter]). Cats are
less likelyto eat their entiremeal in one 10-minute sitting,but
once-a-day feeding is adequate for most healthy adults.
Although manydogs and cats are fed once daily without
noticeable detrimental effects, at least twice daily feeding is
generally recommended.
In summary,how the food is provided and how often it is fed
depend on the animal’s condition and in some cases the lifestyle
of the owner.Each animal’s situation will dictate which feeding
method is most desirable (free choice, time-restricted meal
feeding or food-restricted meal feeding). For many physiologic
and disease conditions this consideration will not be important.
For others it will be very important. Recommendations for the
best method of providing the food and the number of times per
day the food is offered are included in each individual chapter.
Compliance
Owner compliance is necessary for effective clinical nutrition.
Feeding methods should reinforce or enable compliance.
Enabling compliance includes limiting access to other foods
and knowing who provides the food. An animal from a multi-
pet household may have access to the other pets’ food. If so,
such access needs to be denied or limited. Restriction can be
difficult in some homes. In such cases the veterinary health care
team and pet owner may need to compromise.
Compliance can be eroded if everyone in the family does not
support the feeding plan. Whoever feeds the pet must under-
stand the consequences when the wrong foods are fed or even
the right foods are fed in the wrong amounts. Client education
is essential for the successful outcome of any feeding plan.
Specific client education must be provided for feeding healthy
pets and for those with specific disease problems. Both oral and
written instructions encourage compliance with feeding plans.
Veterinarians and their health care teams should actively
involve clients in the formulation of the feeding plan to ensure
commitment to the plan. The hospital staff should strive to
uncover issues that clients may have about the feeding plan and
negotiate mutually acceptable solutions. Open communication
about the client’s and the health care team’s objectives, concerns
and shared responsibilities is necessary for successful imple-
mentation of the feeding plan. Authoritarian approaches are
unlikely to be effective because they discount the high degree of
independent decision making that clients have based on their
own perceptions of nutrition. Veterinarians and their health
careteams can guide clients and enable them to make informed
decisions. For moreabout compliance see Chapter 3.
REASSESSMENT
Finally, monitoring, or reassessing the animal, should be per-
formed at appropriate intervals to evaluate the effectiveness of
the feeding plan. For patients undergoing intensive care,
reassessment may need to be done every few hours, whereas
pets in a health maintenance program could be reassessed
annually. Reassessment signals the initiation of the iterative
step of the clinical nutrition process. Involving the client in an
action plan is an essential component of the veterinarian-client
relationship.The reader is referred to the remaining chapters of
this book for information about specific feeding plans and prac-
tices according to nutritional needs of pets in health and in spe-
cific diseases.
REFERENCES
The references for this chapter can be found at
www.markmorris.org.
Small Animal Clinical Nutrition
18
CASE 1-1
Calcium Supplementation in a Great Dane Puppy
Michael S. Hand, DVM, PhD, Dipl. ACVN*
Hill’s Science and Technology Center
Topeka, Kansas, USA
Patient Assessment
A10-week-old male Great Dane puppy weighing 15 kg was examined as part of its routine health maintenance procedures. The
results of a physical examination were normal. The puppy’s body condition score was 3/5.
Assess the Food and Feeding Method
The puppy is fed a dry lamb and rice-based commercial food. The owner feeds the puppy four 8-oz. measuring cups of food daily.
The owner also provides eight calcium tablets daily as a supplement to “ensure enough calcium.” A phone call to the pet food com-
pany’s customer service department determined that the food’s calcium content is 2.3% and that it provides 3.6 kcal/g (15.1 kJ/g)
on an as fed basis (10% moisture). The customer service department also indicates that the food density is 94 g/cup. Product liter-
ature included with the calcium tablets indicates that each tablet provides 0.5 g of calcium carbonate, and that calcium carbonate
contains 36% calcium (0% moisture). The owner asked if this is enough calcium for the puppy.
Questions
1. How many g of food and how many g of calcium carbonate are being fed (dry matter [DM])?
2. Determine the total amount of calcium (DM) provided by the food and supplement.
3. Determine the percentage of calcium in the DM of the combined food and supplement.
4. Convert the energy density on an as fed basis to DM.
5. Does the combination of the food and supplement meet the calcium requirement for a giant-breed puppy?
Answers and Discussion
1. Four cups x 94 g/cup = 376 g of food. Because the two components being evaluated have differing moisture contents (food =
90% DM and calcium carbonate tablets = 100% DM), it is advisable to convert the food to DM at this point: 376 g of food on
an as fed basis x 90% DM = 338 g food DM.
The owner feeds eight calcium tablets daily.The calcium carbonate source has no moisture so as fed basis equals DM: eight
calcium tablets x 0.5 g calcium carbonate per tablet = 4 g calcium carbonate (as fed and DM).
2. According to the manufacturer, the food provides 2.3% calcium on an as fed basis.To convert this to DM, divide the as fed per-
centage by the DM percentage: 2.3% calcium as fed basis ÷ 90% DM = 2.6% calcium DM.
We have already determined that the calcium tablets provide 4 g calcium carbonate and that calcium carbonate contains 36%
calcium. To determine how much calcium is provided by each component, multiply the amount of each component being fed
by the amount of calcium in eachcomponent and add them:
338 g food dry matter x 2.6% calcium = 8.8 g calcium
4gcalcium carbonate x 36% calcium = 1.4 g calcium
10.2 g total
calcium (DM)
3. Total food DM is the sum of the two components:
338 g food DM + 4 g calcium carbonate DM =
342 g total food DM
10.2 g total calcium (DM) ÷ 342 g total food DM =
3.0% calcium
4. We need to consider the effect of the supplemental calcium source on the energy density of the food and convert the energy den-
sityto DM. In this case, we ignore any dilutional effect the 4 g of calcium carbonate has on the energy density of the food because
it would be inconsequential (4 g ÷ 342 g = 1%). To convert 3.6 kcal ME/g (15.06 kJ ME/g) as fed to DM, as described previ-
19
An Iterative Process
ously, divide the as fed basis by the DM percentage:
3.6 kcal ME/g as fed ÷ 90% DM = 4 kcal ME/g (DM), or
15.06 kJ ME/g as fed ÷ 90% DM = 16.74 kJ ME/g (DM)
Thus, the total food contains 3.0% DM calcium and provides 4 kcal ME/g (16.74 kJ) DM.
5. To compare a food’s nutrient content with a recommended target level requires that the energy density of the food and that spec-
ified for the target level be similar or the same. Calcium is a key nutritional factor (nutrient of concern) for large- and giant-
breed puppies. Calcium levels in foods intended for large- and giant-breed growth should not exceed 1.2% DM in foods that
provide <3.8 kcal ME/g (<15.90 kJ) (Chapter 33). As described above, the conversion is made by generating a multiplier that
converts the requirement to the same energy density as the food. This is done by dividing the food energy density by the require-
ment energy density and multiplying the requirement by the multiplier: 4 kcal ME/g ÷ 3.6 kcal ME/g = 1.1 (multiplier), or 16.74
kJ ME/g ÷ 15.06 kJ ME/g = 1.1 or 1.1 x 1.2% maximum = 1.32% maximum.
In this case, the combined food and supplement are providing excessive calcium for this giant-breed puppy (3% in food vs. 1.32%
maximum recommended) (Chapter 33).
*Current address: Arroyo Hondo, New Mexico, USA.
CASE 1-2
Food Dosage Estimate for a Lactating Queen
Michael S. Hand, DVM, PhD, Dipl. ACVN*
Hill’s Science and Technology Center
Topeka, Kansas, USA
Patient Assessment
A4-kg, three-year-old queen is presented for weight loss.The cat is nursing five, three-week-old kittens. The queen’s body condi-
tion score is 2/5 and the patient record indicates the cat has lost 1 kg since its postpartum checkup.
Assess the Food and Feeding Method
The cat is being fed one cup of a commercial dry food daily,free choice.The food is suitably balanced for feline lactation. The ener-
gy density of the food is 535 kcal metabolizable energy (ME)/cup (2,238 kJ ME/cup) on an as fed basis.
Questions
1. What is this queen’s estimated daily energy requirement (DER)?
2. What should the food dosage be based onthis queen’s DER?
Answers and Discussion
1. Resting energy requirement (RER) (kcal ME/day) = 70(BWkg)0.75
=70(4 kg)0.75 =70(2.83) = 198 kcal ME/day, or
=293(4 kg)0.75 =293(2.83) = 829 kJ ME/day
Modifier for adult feline = 1.5 x RER = DER
DER = 1.5 x 198 kcal ME/day = 297 kcal ME/day, or
1.5 x 829 kJ ME/day = 1,243.5 kJ ME/day
Modifier for feline lactation = (1 + 0.25[number kittens nursing]) x DER
=[1 + 0.25(5)] x 297 kcal ME/day
=2.25 x 297 kcal ME/day = 668 kcal ME/day, or
2.25 x 1,243.5 kJ ME/day = 2,798 kJ ME/day
2. The food being fed has a nutrient profile that is satisfactory for feline lactation.The energy density of the food is 535 kcal (2,238
kJ) ME/cup. Divide the energy requirement by the energy density of the food to determine how much to feed the cat:
668 kcal ME/day requirement ÷ 535 kcal ME/cup = 1.25 cups/day, or
2,798 kJ ME/day requirement ÷ 2,238 kJ ME/cup = 1.25 cups/day
According to these calculations the cat is being underfed. The amount offered free choice should be increased by at least
25%.
*Current address: Arroyo Hondo, New Mexico, USA.
Small Animal Clinical Nutrition
20
CASE 1-3
Altering the Food and Feeding Method for a Young Rottweiler
Rebecca L. Remillard, PhD, DVM, Dipl. ACVN
Angell Animal Medical Center
Boston, Massachusetts, USA
Patient Assessment
Afour-month-old, female Rottweiler was examined for diarrhea of five days’ duration.The puppy had escaped from a fenced yard
on trash pickup day and the owners suspected it had eaten garbage. The puppy appeared bright and alert, weighed 18 kg and had
abody condition score of 3/5. The results of the physical examination were normal except for fluid-filled intestines on abdominal
palpation. The owners described the stools as being small volume but frequent (eight to 10/day) and liquid with some bright red
blood and mucus. A fecal examination was negative for intestinal parasites.
Assess the Food and Feeding Method
The puppy was fed a commercial dry puppy food three times per day until its escape. The puppy still had a good appetite, but
seemed to be drinking more than usual amounts of water. On Day 1 of the diarrheic episode, the veterinarian examined the puppy
and asked the owner to feed a moist commercial veterinary therapeutic food (poultry, egg and rice based) with moderate fat (13%)
and low fiber (<1%) (Prescription Diet i/d Caninea). However, the diarrhea had not resolved after feeding the food for three days.
Question
What is the appropriate food and feeding method for this patient with large bowel diarrhea?
Answer and Discussion
The food was replaced with a moist commercial veterinary therapeutic food that contained 13% fat and 12% crude fiber on a dry
matter basis (Prescription Diet w/d Caninea).The owners were instructed to feed the puppy at its estimated resting energy require-
ment (805 kcal [3,368 kJ]/day) with two cans of the new food divided into four meals per day for one to two days; then to feed at
the estimated daily energy requirement (1,600 kcal/day [6,694 kJ]) with four cans of the new food divided into three to four meals
per day for another two days. The owners were instructed to return for a recheck if the puppy did not have a normal stool by the
fourth day. If the puppy’s stool was normal, the owners were instructed to transition the food back to the original puppy food using
the shortschedule outlined in Table 1-1.
Progress Notes
Nostool was produced within the first 24 hours of feeding the higher fiber food. By the end of the second day the dog had a nor-
mal bowel movement with no blood or mucus.The owners continued to feed the higher fiber food for another two days as instruct-
ed. The puppy was then switched back to the dry puppy food over seven days with no problems.
Endnote
a. Hill’s Pet Nutrition Inc., Topeka, KS, USA.
21
An Iterative Process
CASE 1-3
Altering the Food and Feeding Method for a Young Rottweiler
Rebecca L. Remillard, PhD, DVM, Dipl. ACVN
Angell Animal Medical Center
Boston, Massachusetts, USA
Patient Assessment
Afour-month-old, female Rottweiler was examined for diarrhea of five days’ duration.The puppy had escaped from a fenced yard
on trash pickup day and the owners suspected it had eaten garbage. The puppy appeared bright and alert, weighed 18 kg and had
abody condition score of 3/5. The results of the physical examination were normal except for fluid-filled intestines on abdominal
palpation. The owners described the stools as being small volume but frequent (eight to 10/day) and liquid with some bright red
blood and mucus. A fecal examination was negative for intestinal parasites.
Assess the Food and Feeding Method
The puppy was fed a commercial dry puppy food three times per day until its escape. The puppy still had a good appetite, but
seemed to be drinking more than usual amounts of water. On Day 1 of the diarrheic episode, the veterinarian examined the puppy
and asked the owner to feed a moist commercial veterinary therapeutic food (poultry, egg and rice based) with moderate fat (13%)
and low fiber (<1%) (Prescription Diet i/d Caninea). However, the diarrhea had not resolved after feeding the food for three days.
Question
What is the appropriate food and feeding method for this patient with large bowel diarrhea?
Answer and Discussion
The food was replaced with a moist commercial veterinary therapeutic food that contained 13% fat and 12% crude fiber on a dry
matter basis (Prescription Diet w/d Caninea).The owners were instructed to feed the puppy at its estimated resting energy require-
ment (805 kcal [3,368 kJ]/day) with two cans of the new food divided into four meals per day for one to two days; then to feed at
the estimated daily energy requirement (1,600 kcal/day [6,694 kJ]) with four cans of the new food divided into three to four meals
per day for another two days. The owners were instructed to return for a recheck if the puppy did not have a normal stool by the
fourth day. If the puppy’s stool was normal, the owners were instructed to transition the food back to the original puppy food using
the shortschedule outlined in Table 1-1.
Progress Notes
Nostool was produced within the first 24 hours of feeding the higher fiber food. By the end of the second day the dog had a nor-
mal bowel movement with no blood or mucus.The owners continued to feed the higher fiber food for another two days as instruct-
ed. The puppy was then switched back to the dry puppy food over seven days with no problems.
Endnote
a. Hill’s Pet Nutrition Inc., Topeka, KS, USA.
21
An Iterative Process
... El P es constituyente de fosfolípidos y adenosín trifosfato (ATP), importante para las células y su metabolismo, mientras que el Ca participa en las contracciones musculares (Case et al., 1997). La deficiencia de P en la dieta podría causar alteraciones esqueléticas como raquitismo y osteomalacia (Hand et al., 2000;Laflamme, 2012;Laflamme & Gunn-Moore, 2014). ...
... El sodio (Na) y el cloro (Cl) presentes en la sal, son minerales que participan en el funcionamiento del sistema nervioso, intervienen en la producción y transmisión de los impulsos nerviosos (Case et al., 1997). La deficiencia de sal en la dieta puede ocasionar nerviosismo, menor consumo de agua, debilidad y aumento del ritmo cardiaco en gatos (Hand et al., 2000). ...
... Los gatos son animales carnívoros, que tienen requerimientos especiales en el contenido de proteína de los alimentos (Di Cerbo et al., 2017), una deficiencia de este nutrimento podría causar un crecimiento deficiente en animales en desarrollo, ya que limita el aporte de aminoácidos para la síntesis de tejidos (Lynn Sanderson, 2016). Además, el nivel de proteína es crítico, porque disminuye el aporte de energía de la dieta, debido a que sintetizan glucosa a partir de los esqueletos de carbono de los aminoácidos (Hand et al., 2000;Lynn Sanderson, 2016). ...
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Introduction. The regulations that govern balanced pet food ensure the welfare of pets, public health, and consumer safety, making it valuable to verify the nutritional content declared on labels. Objective. To determine the of the guaranteed analysis of 34 imported foods for dogs, cats, hamsters, rabbits, ornamental fish, and turtles and compare the results with the nutritional recommendations found in the literature. Materials and methods. During the months of August and December of 2018, food samples of dog (10), cat (10), ornamental fish (5), turtles (4), hamster (3), and rabbits (2) food were obtained by direct purchase at different points of sale in San José, Costa Rica. The content of moisture, crude protein (CP), ether extract (EE), crude fiber (CF), calcium, phosphorus, salt, and carbohydrates were analyzed. The average content, standard deviation, maximum and minimum value of each nutrient in each group of food were calculated according to the animal species. The individual and average values obtained were compared with the values declared on the label and the nutritional recommendations found in the literature. Results. The nutrients that presented non-compliances were: salt (27), calcium (16), and energy (14). Additionally, it was found that some foods did not declare the content of salt (14), calcium (9), and phosphorus (7). With respect to the minimum nutritional requirements, twenty-two samples presented deficiencies or excesses in at least one nutriment [carbohydrates (11) and ether extract (7)]. Conclusions. Imported balanced foods for dogs, cats, rabbits, hamsters, turtles, and ornamental fish presented non-compliances in the guaranteed content of CP, EE, CF, ME, Ca, P, and salt declared on the label. The nutritional composition of the evaluated foods limits compliance with the nutritional requirements of the animals, except for rabbits that do comply with the requirements.
... El P es constituyente de fosfolípidos y adenosín trifosfato (ATP), importante para las células y su metabolismo, mientras que el Ca participa en las contracciones musculares (Case et al., 1997). La deficiencia de P en la dieta podría causar alteraciones esqueléticas como raquitismo y osteomalacia (Hand et al., 2000;Laflamme, 2012;Laflamme & Gunn-Moore, 2014). ...
... El sodio (Na) y el cloro (Cl) presentes en la sal, son minerales que participan en el funcionamiento del sistema nervioso, intervienen en la producción y transmisión de los impulsos nerviosos (Case et al., 1997). La deficiencia de sal en la dieta puede ocasionar nerviosismo, menor consumo de agua, debilidad y aumento del ritmo cardiaco en gatos (Hand et al., 2000). ...
... Los gatos son animales carnívoros, que tienen requerimientos especiales en el contenido de proteína de los alimentos (Di Cerbo et al., 2017), una deficiencia de este nutrimento podría causar un crecimiento deficiente en animales en desarrollo, ya que limita el aporte de aminoácidos para la síntesis de tejidos (Lynn Sanderson, 2016). Además, el nivel de proteína es crítico, porque disminuye el aporte de energía de la dieta, debido a que sintetizan glucosa a partir de los esqueletos de carbono de los aminoácidos (Hand et al., 2000;Lynn Sanderson, 2016). ...
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Introducción. La normativa que regula los alimentos balanceados asegura el bienestar de las mascotas, la salud pública y la seguridad al consumidor, por lo que es valioso corroborar el contenido de los nutrimentos declarados en las etiquetas. Objetivo. Determinar el cumplimiento del análisis de garantía de 34 alimentos importados para perros, gatos, hámsters, conejos, peces ornamentales y tortugas, y comparar los resultados con las recomendaciones nutricionales encontradas en la literatura. Materiales y métodos. Durante los meses de agosto y diciembre del año 2018, se obtuvieron muestras de alimento de perros (10), gatos (10), peces ornamentales (5), tortugas (4), hámster (3) y conejos (2); mediante compra directa en diferentes puntos de venta en San José, Costa Rica. Se analizó el contenido de humedad, proteína cruda (PC), extracto etéreo (EE), fibra cruda (FC), calcio, fósforo, sal y carbohidratos. Se calculó el contenido promedio, la desviación estándar, el valor máximo y mínimo de cada nutrimento en cada grupo de alimento, según la especie animal. Los valores individuales y promedios obtenidos se compararon con los valores declarados en la etiqueta y las recomendaciones nutricionales encontradas en la literatura. Resultados. Los nutrimentos que presentaron incumplimientos fueron: sal (27), calcio (16) y energía (14). Además, se encontró que alimentos no declaraban el contenido de sal (14), calcio (9) y fósforo (7). Con respecto a los requerimientos mínimos nutricionales, veintidós alimentos presentaron deficiencias o excesos en al menos un nutrimento [carbohidratos (11) y extracto etéreo (7)]. Conclusiones. Los alimentos balanceados importados para perros, gatos, conejos, hámster, tortugas y peces ornamentales presentaron incumplimientos en los contenidos de PC, EE, FC, EM, Ca, P y sal garantizados en la etiqueta. La composición nutricional de los alimentos evaluados limita el cumplimiento de requerimientos nutricionales de los animales, excepto para conejos que sí se cumple con los requerimientos.
... All biochemical parameters fell into the physiological range for canine species (12). In our study, the highest levels of albumin and lowest concentration of fructosamine were reported in the dogs that were fed the GF2 diet. ...
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Introduction Dog owners have gradually changed their approach, paying more attention to the nutrition and health of their animals. Various pet foods with different ingredients and nutritional characteristics are available on the market. The present study aimed to evaluate the administration of three diets, namely, two grain-free (GF1 and GF2) and one grain-based (CB), with different sources of carbohydrates that can influence the glycemic and insulin postprandial responses in healthy dogs. Materials Fifteen healthy dogs were dived in three groups and alternatively fed each diet for 50 days. Blood samples were collected at beginning of each feeding period. Glycemia and insulin were measured before and after 120, 240 and 360 minutes diet administration to evaluate postprandial responses. Results GF2 diet showed the highest level of albumin and mean insulin concentration ( p < 0.001). Furthermore, the GF1 diet caused the smallest ( p < 0.001) glucose and insulin area under the curve (AUC) and the lowest ( p < 0.05) glucose nadir. Otherwise, GF1 showed the highest ( p < 0.01) insulin time to peak. The GF2 diet showed the highest level of albumin while reporting the lowest amount of fructosamine ( p < 0.05). The diet GF2 registered the highest ( p < 0.001) level of insulin zenith. The cereal-based (CB) diet reported the highest amount of fructosamine ( p < 0.05). The CB diet had the highest levels of glucose and the highest ( p < 0.001) glucose and insulin mean concentrations. Diet CB reported the lowest ( p < 0.001) insulin nadir. Discussion Diets with different carbohydrate sources and chemical compositions could modulate the glycemic response in healthy dogs. Bearing in mind that glycemic/insulin postprandial responses influence energy availability and that different dogs have specific lifestyles, it may be preferable to also consider these aspects when choosing a maintenance diet for animals
... Considering the dog's physical examination, clinical and feeding (Table 1) history, risk factors (10,11) (Table 2), and key nutrients (10) ( Table 3) for each disease (obesity, chronic pancreatitis, and CaOx), a weight loss regimen was advised. The selection of the diet aimed to prevent CaOx by feeding a low relative supersaturation (RSS) diet, prevent pancreatitis by reducing the fat intake, and safely reduce the dog's body weight (BW). ...
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Background: To our knowledge, this is the first description of long-term nutritional management in a dog with paroxysmal dyskinesia. Case summary: An obese 9-year-old, male entire, German Spitz was presented for dietary management after being diagnosed with calcium oxalate urolithiasis and suspected pancreatitis. Since he was seven years old, the dog has had a history of neurological signs, which were thought to be epileptic seizures. He was treated with phenobarbital and potassium bromide and was clinically controlled. For his nutritional advice, aiming to minimize one of the most important risk factors for the diseases, a weight loss program was started and successfully executed. However, 10 months later, the dog restarted presenting neurological episodes at a high frequency (3x/week). Based on videos and the characteristics of the neurological signs, the dog was diagnosed with paroxysmal dyskinesia. To investigate the role of gluten intake on this patient's neurological signs, a dietary trial with a commercial hypoallergenic diet (gluten-free; hydrolyzed protein) was followed. During the 3 months of the dietary trial, four neurologic episodes related to food indiscretion occurred. Upon the decrease in neurological episodes, the anti-seizure drugs were slowly discontinued. During this period, the dog presented only two neurologic episodes that were related to the days that the anti-seizure drugs were decreased. For 4 months the dog remained episode-free. However, a change in the dog's diet to another gluten-free diet (higher fat) led the dog to vomit and experience another neurologic episode. Once the dog was back to the previous gluten-free diet, it clinically improved, and no other clinical signs were reported by the client during the next 5 months. Conclusion: Although a relationship between gluten and paroxysmal dyskinesia cannot be confirmed, the dog's improvement after the nutritional management and the removal of the anti-seizure therapy is supportive of dietary association.
... Proteínas que possuem grande qualidade são aquelas que proporcionam quantidade apropriadas de todos os aminoácidos essenciais. A qualidade é proporcional à efetividade dos aminoácidos convertidos no tecido e, por sua vez, dependem da fonte de proteína, da concentração de aminoácidos essenciais e da sua biodisponibilidade (Thatcher et al., 2010). ...
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... ALT is a hepato-specific enzyme in dogs located in the cytoplasm of hepatocytes and is released when there is light damage to cell membranes. Therefore, ALT is a good parameter for screening liver and heart diseases [23]. ALP, in turn, is not hepato-specific and may be increased when there is cholestasis, hepatic steatosis, or inflammation of the hepatic parenchyma. ...
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We aimed to evaluate the effects of an herbal source of choline on the coefficients of total tract apparent digestibility (CTTAD), diet palatability, fecal characteristics, blood variables, liver morphology, and cardiac function of dogs. Sixteen adult dogs were randomly assigned to two groups (n = 8) which were fed two different diets for 45 days: control, containing 0.28% choline chloride 60, and test, containing 0.14% of an herbal source of choline. Feces were collected between days 39 and 44 to determine nutrient CTTAD and fecal characteristics. On days 0 and 45, blood samples were collected and the liver morphology was evaluated. Cardiac function, in turn, was evaluated only on day 45, and the palatability test was performed on two consecutive days (n = 32). There were no changes in nutrient CTTAD, diet palatability, or fecal characteristics of dogs fed the test diet (p > 0.05). However, on day 45, dogs fed the test diet showed lower (p < 0.05) serum total cholesterol, triglycerides, alkaline phosphatase, and alanine aminotransferase when compared to the control group. We concluded that the herbal source of choline can be a possible substitute for choline chloride in dog nutrition.
... For each animal enrolled, signalment data [(i.e., breed, age (young, mature, old, and geriatric) (Quimby et al. 2021) and sex (male, female and neutered)] as well as baseline information [(i.e., clinical history, concomitant treatments relevant to CKD, antibiotic treatment, laboratory tests and imaging, daily bladder management in spinal cord-injured cats (manual or with catheterisation)] were recorded. A complete physical examination, including body condition score (BCS; based on a 1 to 5 scale with 3 being optimal) (Thatcher et al. 2010), was also performed with particular regard to the presence of clinical signs suggestive of systemic infection (hyperthermia, reduced/absent appetite, vomiting/diarrhoea, cough, sneezing, ocular and nasal discharge, reduce tolerance to physical activity) (DeClue 2017) and/or clinical signs consistent with LUT infection (stranguria, hematuria and pollakiuria). Cats with and without clinical signs compatible with LUTD were included in the study. ...
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Urinary tract infections are defined as the adherence, multiplication, and persistence of an infectious agent within the urogenital system, causing an associated inflammatory response and clinical signs; instead, the presence of bacteria in urine as determined by positive bacterial culture (PUC) from a properly collected urine specimen, in the absence of clinical signs, is defined subclinical bacteriuria. Limited information on the prevalence of PUC in spinal cord injury cats affected by neurogenic bladder (NB) is available. On contrary, in NB dogs and humans the prevalence of bacteriuria is well documented. Moreover, while in humans information about bacteriemia associated with NB is already available, this aspect has never been studied in NB cats. The aim of this prospective study was to determine the prevalence of PUC in cats with NB, compared to animals affected by chronic kidney disease (CKD) and healthy cats. Furthermore, the prevalence of bacteriemia in cats with NB was evaluated. Fifty-one cats met the inclusion criteria: 12 cats were affected by NB, 22 had CKD and 17 were healthy. The prevalence of PUC was 58.33% and 18% in NB and CKD cat populations, respectively. All blood cultures were negative. The incomplete bladder emptying and the decreased resistance in the bladder wall could be considered predisposing elements to PUC in the NB feline population. The results of this study highlight, for the first time, an high prevalence of PUC in cats affected by NB, which was not found to be associated with bacteriemia.
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Canine atopic dermatitis (CAD) is a common, chronic, inflammatory skin disease in dogs worldwide. This disease often predisposes for secondary organisms overgrowth and skin infections with pathogens, such as Staphylococcus pseudintermedius and Malassezia pachydermatis. Unfortunately, the causes of this disease in both humans and animals are not fully understood; therefore, the only possible option is a lifelong, symptomatic treatment. The management of CAD is mainly based on limiting contact with allergens and antipruritic therapy, most often with glucocorticoids and antihistamines. A serious problem in this situation is the fact, that long-term administration of glucocorticoids leads to side effects like polyuria, alopecia, increased susceptibility to infection, muscle atrophy, and many others. For this reason, great emphasis is placed on the development of replacement and supportive therapies. It is a well-documented fact that reduced concentrations of serum vitamin D3 contribute to the severity of atopic dermatitis symptoms in humans. Moreover, unlike the most commonly used therapeutic methods, of which the main goal is to ameliorate inflammation and pruritus, namely the symptoms of AD, vitamin D3 supplementation affects some underlying factors of this disease. Therefore, in this review, we summarize the current state of knowledge regarding the role of vitamin D3 in CAD, its protective effect against secondary bacterial and fungal infections, and the potential of its supplementation in dogs.
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Elevations in circulating trimethylamine N-oxide (TMAO) and its precursors are observed in humans and dogs with heart failure and are associated with adverse outcomes in people. Dietary intervention that reduces or excludes animal ingredients results in rapid reduction of plasma TMAO and TMAO precursors in people, but the impact of diet in dogs has not been studied. The objective of the current study was to determine the effect of diet on plasma TMAO and 2 of its precursors (choline and betaine) in dogs fed a commercial extruded plant-based diet (PBD) or a commercial extruded traditional diet (TD) containing animal and plant ingredients. Sixteen healthy adult mixed breed dogs from a university colony were enrolled in a randomized, 2-treatment, 2-period crossover weight-maintenance study. Mean (SD) age and body weight of the dogs were 2.9 years (± 1.7) and 14.5 kg (± 4.0), respectively. Eight dogs were female (3 intact, 5 spayed) and 8 dogs were male (4 intact, 4 castrated). Plasma choline, betaine and TMAO were quantified by LC-SID-MRM/MS at baseline, and after 4 weeks on each diet. Choline and betaine were also quantified in the diets. Plasma choline levels were significantly lower (P = 0.002) in dogs consuming a PBD (Mean ± SD, 6.8 μM ± 1.2 μM) compared to a TD (Mean ± SD, 7.8 μM ± 1.6 μM). Plasma betaine levels were also significantly lower (P = 0.03) in dogs consuming a PBD (Mean ± SD, 109.1 μM ± 25.3 μM) compared to a TD (Mean ± SD, 132.4 μM ± 32.5 μM). No difference (P = 0.71) in plasma TMAO was detected in dogs consuming a PBD (Median, IQR, 2.4 μM, 2.1 μM) compared to a TD (Median, IQR, 2.3 μM, 1.1 μM). Betaine content was lower in the PBD than in the TD while choline content was similar in the diets. Our findings indicate consumption of a commercial extruded PBD for 4 weeks reduces circulating levels of the TMAO precursors choline and betaine, but not TMAO, in healthy adult dogs.
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