Chapter 4 The Role of Nutrition in Canine Performance and Rehabilitation 79and colleagues examined diets of approxi-
mately 72 and 85 g/1000 kcal and showed that
there was no difference in the hematocrit
decline over a 6‐month period of training, but
the higher protein group had elevated post‐
exercise hematocrit, further suggesting that
protein may affect parameters associated with
performance (Querengaesser et al., 1994). An
interesting study of mongrel dogs exercised
4 hours per day at 12 km/h compared soy
protein versus fish meal‐based protein at
approximately 35% of the ME. After 3 weeks,
this study showed decreased hematocrit, and
increased red blood cell fragility in the dogs
fed soybean meal (Yamada et al., 1987). These
data suggested that endurance dogs should
receive minimally 70 g/1000 kcal (approxi-
mately 26% of ME) of highly digestible
animal‐source protein with no upper limit yet
defined.
In sprinting dogs, the picture may be slightly
different as Hill and colleagues performed
studies suggesting that racing Greyhounds per-
form better on lower protein diets of 63 g/1000
kcal versus 106 g/1000 kcal (Hill et al., 2001b).
These diets substituted carbohydrates for the
protein in an isocaloric exchange of nutrients;
therefore the enhanced performance may have
been due to the increased carbohydrate in the
diet, not the lack of protein. Though it appears
that approximately 60 g/1000 kcal may be
adequate for racing Greyhounds, further
decreases in protein have not been evaluated
and are very contrary to current feeding prac-
tices. Most Greyhounds are provided 0.25–0.5
kg of meat mixed with dry commercial dog
food, approaching 106 g/1000 kcal to meet their
energy requirements (Kohnke, 1998; Hill, 1998).
The differences noted in sprinting dogs and
endurance dogs may be related to overall mus-
cle turnover rates, as exercise leads to increased
protein turnover, and increased muscle inflam-
mation observed with increased duration of
exercise (Wasserman et al., 1988, 1989, 1991;
Wakshlag et al., 2002a). Without firm recom-
mendations or studies in sprinting dogs, a rea-
sonable recommendation is that most sprinting
and intermediate activity dogs receive mini-
mally 60 g/1000 kcal consumed (22–24% ME).Dietary fat and carbohydrate—energy
and demandsThe respiratory quotient (RQ) is the ratio of
oxygen consumed to CO 2 generated. If the RQ
is close to 0.7, primarily fat is being consumed
for CO 2 production, while if the RQ is closer to
1 primarily glucose is being consumed
(Figure 4.6). Early in exercise (the first 20–30
minutes) protein oxidation is minimal, there-
fore substrate utilization and changes in oxygenRunning speed (% maximum)Low intensityModerate intensityHigh intensity120100806040200
020406080100Vo 2 maximumOxygen consumption(%Vo(^2)
maximum)
Figure 4.6 Depiction of running speed versus the maximal oxygen consumption. Note that the Vo2 max is reached well
before maximal speed is reached reflecting the generation of energy by anaerobic glycolysis, which can only be
sustained for short periods of time. Vo2 max is often reached at between 65 and 75% of maximal running capacity. Source:
Picture reproduced from Hand et al., 2010.