Page 65 - Small Animal Clinical Nutrition 5th Edition

Macronutrients 65

30 and 90 days postneutering, respectively (Anatharanman- under various disease conditions (Chapters 25 and 26).
VetBooks.ir Barr, 1990). which the RER and DER are used as references to assess
One investigator recommended a practical approach in
whether a sick animal’s voluntary food consumption is ade-
BREED
Some breeds such as Newfoundlands and huskies have rela- quate or inadequate (Burkholder, 1995). Forced nutritional
tively lower energy requirements, whereas Great Danes have intervention is recommended if food consumption is less than
energy requirements above the average (Kienzle and Rainbird, the calculated RER. If food intake approaches DER for adult
1991; Rainbird and Kienzle, 1990; Zentek and Meyer, 1992). maintenance, additional nutritional support is probably not
Breed-specific needs probably reflect differences in: 1) tem- needed. Regardless of whether a sick animal consumes food
perament (resulting in higher or lower activity), 2) stature, 3) voluntarily or is forced to eat, the food should have a nutrient
insulative capacity of skin and coat (which influence the degree composition that is optimized for recovery as discussed in
of heat loss) and 4) lean body mass. However, when data are Chapters 25 and 26.
corrected for age, interbreed differences become less important
(Finke, 1994). WEIGHT LOSS/UNDERWEIGHT
The prevalence of suboptimal body condition begins to
GENDER increase at about 11 years of age and rises sharply in very old
In people, gender has a significant effect on energy require- animals, especially cats (Armstrong and Lund, 1996). Anorexia
ment because of the proportionately greater muscle mass of is common in elderly people and can also occur in older cats
men. (Women have a greater proportion of body fat.) No effect and dogs. Changes in appetite can be influenced by many fac-
of gender, however, has been found in dogs (Männer, 1991; tors including decline in acuity of taste and smell, dental prob-
Kienzle and Rainbird, 1991) or reported to occur in cats. lems, physical disabilities, acute or chronic diseases, drugs and
other therapies including dietary modifications. Prolonged
DISEASE, INJURY, INFECTION reductions in food intake ultimately lead to chronic energy
AND CANCER deficiency. As a result, loss of body weight occurs as body ener-
As a result of metabolic and physiologic changes, animals gy stores are diminished (fat and muscle protein).
must recover from trauma, repair wounds, mount an immune In people, data show that reductions in body weight are lin-
response or compete with cancer to survive. These processes early related to reductions in RER and are described by the
involve cellular work that requires energy. Energy-supplying regression equation resting energy requirement (REE)
nutrients must be provided in sufficient amounts to prevent (kcal/day) = -78.8 + 11.9 x weight change (kg) (Saltzman and
catabolism of body tissues with resultant loss of function. Roberts, 1995). Decreases in lean tissue lead to decreased pro-
However, most sick animals are inactive and anorectic and; tein turnover, which reduces energy expenditure. Thus, reduc-
therefore, their energy requirement is reduced. Thus, energy tions in RER are due in part to reductions in body protein
requirements for diseased animals logically lie somewhere turnover and reduced body size. Other factors such as changes
between RER and DER. Although mathematical factors have in Na-K ATPase activity, hormonal changes affecting nutrient
been reported to multiply times RER (or MER) to estimate metabolism and alterations in sympathetic nervous system
energy requirements for diseased dogs and cats (Kronfeld, activity may also reduce overall RER in weight loss (Saltzman
1991; Hill, 1993; Donoghue, 1989; Remillard and Thatcher, and Roberts, 1995). Data from obese dogs suggest that RER
1989), very few studies have verified their validity by measuring may be reduced by up to 25% following a weight loss of 17%
the actual energy requirements of hospitalized dogs and cats (Brown, 1991). It is unknown whether similar reductions in

Box 5-6. Quick Canine Feeding Guide.
Unlike cats, dogs come in variable sizes from Chihuahuas to Great Danes. Therefore, the same assumptions cannot be made when simpli-
fying food offerings for dogs. However, daily feed offerings can be simplified for the initial food offering in kcal/lb body weight (Table 1).
Table 1. Summary of caloric food offerings per day.*
BW (lb) Weight loss (1.0 x RER) Inactive/obese prone (1.4 x RER) Maintenance (1.6 x RER)
<10 20 kcal/lb 28 kcal/lb 32 kcal/lb
10–20 15 kcal/lb 21 kcal/lb 24 kcal/lb
>20 9 kcal/lb 13 kcal/lb 15 kcal/lb
Key: BW = body weight, RER = resting energy requirement.
*Example: A 15-lb dog would require 225 kcal/day (15 lb x 15 kcal) for weight loss.
If a wet food contains 150 kcal/can then offer the dog 1 and 1/2 cans per day.
If a dry food contains 300 kcal/cup then offer the dog 3/4 cup of food per day.
These are starting points and food offerings should be adjusted to maintain or achieve the desired body weight.