Page 62 - Small Animal Clinical Nutrition 5th Edition

62 Small Animal Clinical Nutrition

The energy values expressed in this text are based on the expo-
VetBooks.ir nent (BW ) because: 1) there is greater size diversity among
0.75
kg
dogs than for other species (e.g., 1 kg for a Chihuahua to 90 kg
or more for a St. Bernard), 2) changes in lean body mass are of
primary interest, 3) this equation works well for other mam-
mals and 4) it can be easily calculated by cubing body weight in
kg and then taking its square root twice.

LIFESTAGE
Adult Maintenance
Estimates of the DER for dogs range between 95 to 200
kcal (397 to 850 kJ) of DE per (BW ) 0.75 per day (NRC,
kg
2006; Durrer and Hannon, 1962; Leibetseder, 1978; Meyer,
1983), which represents a surprisingly wide range. Differences
Figure 5-9. Comparison of three methods for calculating resting
in activity levels of dogs account for much of this range. Other
energy requirement (RER).
factors that contribute to differences in energy requirements
include differences in breed, temperament, skin and coat
based on body surface area or metabolic body size or a linear insulation, age, social environment and differences in
formula to predict energy requirements for dogs and cats is methodology used to estimate the requirement. For the aver-
largely academic (Männer et al, 1991; Männer, 1991; Kienzle age sexually intact healthy adult dog, the DER approximates
and Rainbird, 1991; Finke, 1994; NRC, 2003). Figure 5-9 1.8 x RER.
compares energy requirements calculated using several different Non-obese adult domestic cats vary in body weight from
published methods. These equations yield similar estimates, approximately 2.5 to 6.5 kg, which is a much smaller range of
especially at intermediate weight ranges. To practicing veteri- weight extremes than exists for dogs.The NRC recommends a
narians, the differences in the energy requirement predicted by DER for adult cats of 70 to 90 kcal/BW kg (290 to 380
using one exponent or another or a linear equation compared to kJ/BW ) (1986). However, Earle and Smith reported that
kg
an exponential equation are small. For example, Figure 5-10 inactive cats required less energy (39 to 66 kcal/BW kg or 162
demonstrates results among dogs and cats when the average to 278 kJ/BW ) and, similar to what is seen in dogs, they
kg
energy consumed is set at 100%. In 95% of 120 dogs, the ener- found that the energy intake per unit body weight was lower in
gy consumed varied from 65 to 135% (range 43 to 152%); in heavier cats (Earle and Smith, 1991). Generally, the DER for
95% of 76 cats, it varied from 61 to 139% (range 50 to 146%). adult intact cats is about 1.4 x RER. Energy requirements are
Thus, the amount of food needed by dogs and cats for mainte- lower for neutered animals (discussed below).
nance, even under similar environmental conditions and when
kept in cages or runs, varied threefold. Even when the extremes Growth
are excluded (the top and bottom 2.5%), the amount of energy Energy needs for growth are increased above maintenance
needed varied more than twofold. because energy is needed to form new tissue. However, growth
The following sections discuss differences in energy require- is a dynamic process; its rate declines as animals approach
ments for different physiologic and environmental conditions. maturity.Therefore, the amount of energy needed also declines

Figure 5-10. 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 LD, Morris ML Jr, Hand MS. Small Animal Clinical Nutrition III. Topeka, KS: Mark Morris Associates, 1987; 1–10.)