Nutritional Math Review Questions

Resting energy requirements are based on what?

RER is based on the energy needed to maintain essential body functions at rest, such as breathing, circulation, and temperature regulation.

What calculations provide an estimate of energy use?

• Resting Energy Requirement (RER) = energy for basic body function.

• Daily Energy Requirement (DER) = RER × activity or life stage factor to estimate total daily energy use.

Why is the allometric formula used most often?

Because it is the most accurate and widely accepted formula across species and body weights. It works for small and large animals and accounts for metabolic scaling.

What does ME mean?

Metabolizable Energy – the usable energy from food after losses in feces, urine, and gases; expressed in kilocalories (kcal).

What does kcal mean?

Kilocalorie, a unit of energy equal to 1,000 calories, used to measure energy in food.

What conditions can affect DER calculations?

• Life stage (growth, adult, senior)

• Activity level

• Pregnancy or lactation

• Illness or hospitalization

• Environmental temperature

Each condition changes the activity factor used to calculate DER.

What values do you need to calculate the feeding volume for an animal?

• The food’s metabolizable energy (ME) (kcal/kg or kcal/can)

• The animal’s RER or DER

• The food’s moisture percentage (to convert to dry matter if needed)

What is the difference between liquid and dry measuring cups? Why does it matter which is used to measure food?

• Liquid cup measures volume of fluids (8 fl. oz.)

• Dry cup measures weight/volume of solids (8 oz dry)
  They’re not interchangeable — using the wrong one can cause over- or underfeeding errors, especially with calorie-dense foods.

What % of the diet should be fed as treats?

No more than 10% of the pet’s total daily caloric intake should come from treats.

How does BCS/MCS relate to the determination of RER/DER?

BCS and MCS help evaluate current nutritional status.
If BCS is high (overweight), use ideal weight for RER/DER.
If underweight or low MCS, adjust feeding to promote healthy weight or muscle gain.

What does AABW (listed on your card) mean, and why is that important for puppy energy requirements?

Average Adult Body Weight.
Used to predict final growth size and determine proper DER factors. Large and giant breeds require controlled growth to prevent developmental orthopedic disease (DOD).

What is DOD? Which breeds are at risk, and why?

Developmental Orthopedic Disease – growth-related bone/joint disorders caused by excess calories or rapid growth.
Large and giant breeds (e.g., Great Danes, Labs) are most at risk because of their fast growth rates and heavy body mass.

Calculate % dry matter utilizing pet food label

Formula:
100 – % moisture = % dry matter

Example:
82% moisture → 100 – 82 = 18% DM

Compare diet components based on % DM

Formula:
(% nutrient as-fed ÷ % dry matter) × 100 = % nutrient DM

Example:
8% protein AF, 18% DM → (8 ÷ 18) × 100 = 44.4% protein DM

Calculate RER from pet history and card

Formula:
RER = 70 × (Body Weight in kg)^0.75

Example:
Dog weighs 10 kg → 70 × (10^0.75) = ~395 kcal/day

Determine appropriate DER factor based on pet age/activity

Use an activity factor from quick reference:

• Growing puppy: 2–3 × RER (based on AABW)

• Adult maintenance: 1.4–1.8 × RER

• Active working dog: 2–8 × RER

• Weight loss: 1 × RER

Calculate DER from pet history and card

Formula:
DER = RER × Activity Factor

Example:
RER = 395 kcal/day, factor = 1.6 →
DER = 395 × 1.6 = 632 kcal/day

Calculate feed portion based on RER/DER

Formula:
Daily kcal need ÷ kcal per can or per kg = feeding amount

Example:
DER = 632 kcal/day
Food = 400 kcal/can → 632 ÷ 400 = 1.58 cans/day

Calculate feeding costs for diet comparison

Formula:
Cans/day × cost/can = daily cost
Daily cost × 30 = monthly cost

Example:
1.5 cans/day × $1.79 = $2.69/day
$2.69 × 30 = $80.70/month

Why are these calculations important?

They allow technicians to create individualized, accurate feeding plans, prevent over- or underfeeding, and help monitor and adjust as pets grow or health conditions change.