Front Matter

76 Canine Sports Medicine and Rehabilitation

dog working at maximal oxygen consumption

would need approximately 700–900 kcal per

hour of work based on the experimental condi-

tions set forth in simulated treadmill exercise

(Ordway et al., 1984; Musch et al., 1985; Reynolds

et al., 1999). This oxygen consumption is directly

related to skeletal muscle mitochondrial den-

sity and volume. In the field, there are many

other factors to take into consideration such

as  external temperature, thermal regulation,

Acyl-CoA

Acetyl-CoA

ATP

Oxidative

phosphorylation

β-oxidation

Mitochondrial

matrix

CO 2 ATP

H 2 O

TCA cycle

NADH

FADH 2

Acyl carnitine

Carnitine Acyl carnitine

CoA

Cytosol

Fatty acid

Fatty acyl-CoA

Carnitine-acyl transferase II

Carnitine-acyl transferase I

Carnitine

CoA

Figure 4.4 Fatty acid entry into the mitochondria is
dependent on carnitine‐mediated transport through both
the outer and inner mitochondrial membranes via
carnitine palmitoyl transferase 1 and carnitine
acylcarnitine translocase. After fatty acid transport
carnitine is recycled through the actions of carnitine
palmitoyltransferase II. Fat within the mitochondria will
then undergo beta‐oxidation and entry of acetyl CoA into
the citric acid cycle. Source: Picture reproduced from
Hand et al., 2010.

Box 4.2 Calculations for resting and active energy requirements

Linear equation for a 30‐kg dog

Restingenergyrequirement BWkg kcal

Activemainten

30 70 970

aance energyrequirement 2307 BW 0 1940 kcal

Exponential equation for a 30‐kg dog

Restingenergyrequirement BWkg kcal

Activemainte

70 07.^5897

nnancerequirement 140 BWkg^07.^51794 kcal

Box 4.1 Atwater’s and modified Atwater’s

equations

The following formulas demonstrate the use of

Atwater’s formula and modified Atwater’s formula,

respectively, to calculate kcal in a pet food that

consists of 24% protein, 12% fat, and 50% carbo-

hydrates on a dry matter basis in 100 g. Note the

modest differences between the two equations. The

modified Atwater’s equation is used to calculate

most commercial pet foods and can potentially

undercalculate the number of kilocalories in highly

digestible foods.

Atwater’s formula

Protein kcal/g kcal

Fat kcal/g kcal

Carbohydrat

42496

912 108

ee kcal/g kcal

Totalkcal kcal

450 200

(^404)
Modified Atwater’s formula
Protein kcal/g kcal
Fat kcal/g kcal
Carbohy
35 24 84
85 12 102
.
.
ddrate kcal/g kcal
Totalkcal kcal
35 50 175
361
.