82 Canine Sports Medicine and Rehabilitation
animals, including Foxhounds, hunting dogs,
and service dogs, rely on detection capabilities,
the potential use of polyunsaturated fatty acids
in olfaction is of interest. A small study using
only four dogs in a Latin square design showed
that olfactory performance was affected by
altering fat content in the diet by adding either
corn oil rich in polyunsaturated fatty acids or
medium‐chain triglycerides from coconut/
palm oils. This study suggested that corn oil
and its high linoleic acid might enhance olfac-
tory capability in pointers. More importantly,
scent detection may decrease with the use of
medium‐chain triglycerides (Altom et al., 2003).
More recently a study looking at dietary fat
and protein:fat ratios in the diet suggested
that detection of target in trained detection
Labradors was slightly better on a high corn oil
diet where 54% of the ME was fat and only 18%
of the ME was protein (Angle et al., 2014).
Whether this was due to substrate utilization or
the high polyunsaturated nature of the fat
affecting olfaction cannot be determined, but
physiologically the dogs on the corn oil‐based
high‐fat diet had better thermal recovery from
exercise (Ober et al., 2016). Another study exam-
ining hunting dogs suggested that a diet with
slightly higher protein and higher fat improved
bird find rates (Davenport et al., 2001). Whether
this was due to the altered substrates, differ-
ences in ingredients, or long‐chain polyunsatu-
rated fat enrichment could not be determined
based on the experimental design.
Carbohydrates—timing and strategy
The use of carbohydrates as a major dietary
substrate makes sense in sprinting animals like
Greyhounds, with approximately 40–50% of
the ME in the diet as highly digestible carbohy-
drates. Endurance sled dogs may need less than
15% of the ME as carbohydrates, as there are no
definitive carbohydrate requirements (Reinhart,
1998; Hill et al., 2001b), although this is now
up for debate with findings of robust glucose
utilization in endurance sled dogs (Miller et al.,
2015).
Carbohydrate loading is a principle used in
human athletics, which can translate into the
canine arena. It may be beneficial for sprinting
and intermediate athletes, particularly over
multiple‐day events, where muscle glycogen
is depleted daily and needs to be replenished
(Reynolds et al., 1997; Wakshlag et al., 2002b;
McKenzie et al., 2008). Studies performed in
sled dogs have definitively shown that post‐
exercise supplementation with a maltodextrin
supplement at 1.5 g/kg BW within 30 minutes
of exercise increases skeletal muscle glycogen
within 4 to 24 hours. In both studies, it was
evident that this dosing returned muscle
glycogen to baseline concentrations before
exercise the following day, while without sup-
plementation skeletal muscle glycogen con-
tent was only 50% of baseline concentrations
(Reynolds et al., 1997; Wakshlag et al., 2002b).
Based on this information, post‐exercise car-
bohydrate repletion is recommended in dogs
running anywhere between 5 minutes and 3
hours per day, particularly when expected to
perform similarly the following day. The
effectiveness of this strategy in endurance
events is unknown and is not routinely
recommended.
In the human athletic arena, protein with
carbohydrate is often provided post exercise.
The protein is thought to help curb skeletal
muscle proteolysis after intermediate exercise
(Betts & Williams, 2010). This approach has not
been examined in the canine performance
arena. In human athletics, the use of whey‐
based protein in young athletes post exercise
appears to help in retention of lean mass andTable 4.2 Differences between medium‐ and long‐chain triglycerides
Medium‐chain triglycerides Long‐chain triglyceridesChain length 10–14 carbons long 16–22 carbons long
Kilocalories per gram Approx. 8 kcal Approx. 9 kcal
Primary GI absorption Direct enterocyte to portal blood Synthesis into chylomicrons
Transport in blood Carried via albumin Chylomicrons and lipoproteins
Cell absorption Diffusion Lipase‐dependent absorption