Page 339 - Small Animal Clinical Nutrition 5th Edition

346 Small Animal Clinical Nutrition

and supplements. When assessing the overall ration, it is
Box 18-8. Acid-Base Balance and Exercise.
VetBooks.ir important to assess all foods and supplements fed.The nutrient
profile of the total daily ration should be evaluated for the key
nutritional factors based on the type and amount of exercise
Muscle contraction produces metabolic acid (CO and/or lac-
2
tate), which decreases the intracellular pH of muscles. performed by each dog.
Changes in intracellular pH can affect the function of muscle Most intermediate athletes are fed commercial foods, where-
enzymes responsible for ATP generation and contraction. The as many elite sprint and endurance athletes (racing dogs) are
mechanisms that act to blunt the detrimental effects of acid fed homemade foods or more commonly a mixture of commer-
production within muscles include: 1) intracellular buffering cial food and other ingredients. The use of supplements is
and 2) removal of acids by the bloodstream. prevalent with working and sporting dogs of all types.
In equine athletes, two approaches have been used to help Comparing the nutritional content of the current food to the
counteract exercise-induced acidosis to improve athletic per-
formance. The first is to base load the horse via stomach tube key nutritional factors allows decisions to be made about the
several hours before exercise. Sodium bicarbonate in water is adequacy of the food for individual dogs. If the current food is
the base used most often. This solution is frequently called a appropriate (key nutritional factors in balance with the dog’s
“milkshake” due to its milky white appearance. This approach needs) then that food can continue to be fed. If discrepancies
can effectively alter resting acid-base status, but hasn’t been exist between the key nutritional factors for the dog and the
proven to alter performance. The second approach is to alter content of the food, the food should be changed or “balanced”
the ionic composition of food to change the acid-base status to meet the dog’s needs.
of the animal. Investigators have been able to alter resting
acid-base status by altering the dietary cation-anion balance Commercial Foods
of the food, but again it is unclear if this alteration affects per- Table 18-12 lists the key nutritional factors for working and
formance. Alteration of acid-base status by dietary or supple- sporting dogs and compares them to the key nutritional factor
mentation means has not been investigated extensively in
dogs; however, the basic principles investigated in horses content of selected commercial foods formulated for these
should apply to dogs. dogs. For those commercial foods not found in Table 18-12,
minimum fat and protein levels are listed in the guaranteed or
The Bibliography for Box 18-8 can be found at typical analysis on the pet food label. (See Chapter 1 for limi-
www.markmorris.org. tations of this information.) The carbohydrate portion of a food
can also be estimated as described above under “Carbohydrates”
in the “Key Nutritional Factors” section or in Chapter 5.
Digestibility information is usually only available from the
cally dense so that canine athletes can consume enough food to manufacturer. The energy density of most commercial foods is
meet their energy requirements. Second, the food must be not high enough for dogs engaged in true endurance activity.
acceptable and highly digestible. DM digestibility should Table 18-12 provides energy density information for commer-
exceed 80% (Downey et al, 1980; Lewis et al, 1987). High cial foods supplemented with vegetable oil in order to meet the
digestibility reduces fecal bulk and fecal water loss and may energy density needs for endurance athletes.
decrease the risk of developing stress diarrhea (Houpt, 1984;
Downey et al, 1980). Finally, the food should be practical. Homemade Foods
Factors such as the cost of the food, the form of the food, the Homemade foods can be very complicated mixtures of many
environment in which the food is stored and fed and the num- ingredients. Chapter 10 discusses assessment of homemade
ber of dogs being fed are all important considerations. What is foods in detail. Fortunately, most recipes for homemade foods
practical for a single hunting dog at home may not be practical for working and sporting dogs use a commercial dry dog food
for a team of sled dogs hundreds of miles from civilization, as a base. Many racing greyhound food regimens contain dry
agility dogs at an out-of-town competition or racing grey- dog food mixed with either raw or cooked meat,water,vitamin-
hounds at a track. mineral supplements and a variety of other ingredients.
Because the greatest nutritional demand of exercise is for Likewise, many sled-dog mushers mix animal fat or both meat
energy, foods for canine athletes must provide sufficient kcal and fat with dry dog food and other ingredients. If the com-
from the right sources. Increasing the fat content of the food mercial dry food constitutes 50 to 75% of the mixture on a
usually enhances energy density. The appropriate fat content is weight basis and most of the added ingredients are wet ingre-
dictated by energy need and exercise intensity. Dogs participat- dients or fat, it is unlikely that vitamin and mineral deficiencies
ing in short-duration, maximal exercise may benefit from lower will occur.
fat, higher carbohydrate foods. Because many elite canine athletes (racing greyhounds and
Assessment of the food includes: 1) physical evaluation of the sled dogs) are fed homemade foods containing meat and ani-
food, 2) evaluation of the product label for commercial foods mal by-products of variable quality, the safety of these foods
and 3) evaluation of the food’s nutritional content relative to the should always be evaluated. Some raw meat sources contain
animal’s needs (key nutritional factors) (Chapter 1). abundant bacteria and bacterial toxins (Case 11-1). Raw
Working and sporting dogs are fed a wide variety of foods foods may pose a health hazard for people who care for these