Energy Needs of the Canine

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Energy Needs of the Canine

• AS 223

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Energy

• With exception of water, most critical component
  to consider in a diet
• Energy is necessary for performing metabolic work
• Maintaining and synthesizing body tissues
• Engaging in physical work
• Regulating body temperature

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Energy Intake

• Animals are capable of regulating their energy
  intake to accurately meet their daily caloric
  requirements
• Energy density Concentration of energy in a
  given quantity of food
• If FI is regulated by energy intake, all other
  nutrients must be balanced with respect to energy
  density

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Measurement of Energy in the Diet

• No measurable mass, but chemical energy contained
  in foods is ultimately transformed by body into
  heat, which can be measured
• Nutrients that provide energy
• Fat, CHO, proteins

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Measurement of Energy in the Diet

• Calorie Amount of energy required to raise 1 g
  of water, 1? C (14.5? C - 15.5? C)
• Bomb calorimeter allows us to measure the gross
  energy of a substance
• Measures the ? heat when a known amount of sample
  is ignited by monitoring the temperature of the
  surrounding water
• Gross Energy (GE) Energy released as heat when
  an organic substance is completely oxidized to
  CO2 and H2O

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Partitioning of Feedstuff Energy
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Metabolizable Energy

• Amount available to tissues of the body after
  losses to urine and feces
• Most often used to express energy concentration
  of pet food diets
• Energy requirements of dogs/cats expressed as
  kcal of ME

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Metabolizable Energy

• Depends on nutrient composition of food AND
  animal consuming the food
• Due to length of GIT a horse can derive more
  energy from grass than a dog
• So higher ME for grass for horses than dogs

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Determination of Energy Density

• Feeding trials
• Calculation methods
• Extrapolation from other species

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Calculation of ME

• ME values can be determined using mathematical
  formulas that estimate a foods ME from its
  analyzed CHO, protein, and fat content
• The formula contains constants that account for
  fecal and urinary losses of energy

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Calculation of ME

• Atwater factors (4-9-4) commonly used to
  estimate ME for CHO, fat, and protein
• Assumes digestibility of 96, 91, 96
• Data from humans
• Digestibility lower for pet food
• Digestibility 85, 80, 90
• Modified Atwater Factors 3.5-8.5-3.5

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Modified Atwater Factors

• Provide better estimate of ME values for pet
  foods
• Highly digestible protein sources/low fiber
• ME underestimated
• Poor quality protein/high fiber
• ME overestimated

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Calculation of ME in commercial pet foods

• Studies shown following equation is a good
  estimation of ME content of pet foods
• ME 3.075 0.066 fat
• fat on pet food label

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Nutrient Density

• Since FI is determined by energy density, it is
  more appropriate to express nutrients on a
  density related to energy
• Expressing nutrient content as units per 1000
  kcal of ME

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Calculation of nutrient density of commercial pet
foods
For Example, Dry Food 27 CP, 3800
kcal/kg Canned Food 7 CP, 980 kcal/kg
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Calculation of nutrient density of commercial pet
foods using guaranteed analysis
To calculate energy density 383 kcal/100 g
1000g/kg 3830 kcal/kg
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Food Intake as related to Energy Density

• Energy density is needed to estimate amount of
  food required daily
• Knowing energy requirement of adult dog is 1100
  kcal/d, how much of the food from previous slide
  should we feed?

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Food Intake as related to Energy Density

• Step 1
• 1100 kcal/d 3830 kcal/kg 0.39 kg/d
• Step 2
• 0.39 kg/d 2.2 lb/kg 0.85 lb/d
• Step 3
• 0.85 lb/d 16 oz/lb 13.63 oz/d
• Step 4 (assuming cup 3 oz food)
• 13.63 oz/d 3 oz/cup 4.5 cups/d