Front Matter

84 Canine Sports Medicine and Rehabilitation

should be between 0.6 and 1.2% dry matter,
with similar amounts of phosphorus to main-
tain calcium homeostasis for structural integ-
rity of bone and appropriate cellular signaling
and buffering capacities (National Research
Council, 2006c). Magnesium is also a concern
when bone is not a constituent in a nontradi-
tional diet when commercial feed is not
being used. Deficiency can manifest in exer-
cising dogs as hyperextension of the carpus.
Deficiencies of other major minerals including
sodium, potassium, and chloride have never
been observed in adult working dogs. However,
nonclinical hyponatremia has been observed in
endurance Huskies during races and simulated
endurance races (Hinchcliff et al., 1993, 1997a,
1997c; McKenzie et al., 2007). It is believed that
due to the high calorie meat consumption and
high water turnover rate during these strenu-
ous exercises, sodium conservation is height-
ened by increases in the renin/aldosterone/
angiotensin system as well as modest sodium
loss causing a mild hyponatremia and hypoka-
lemia (Hinchcliff et al., 1997a, 1997c). It must be
noted that this chronic hyponatremia was
observed in the Yukon quest in 1992 and simu-
lated endurance events with a specific kennel
(Burr et al., 1993; Hinchcliff et al., 1997a, 1997c).
Studies examining this phenomenon in three
teams participating in the 2012 Yukon Quest
suggest that each team responded differently.
One team was provided with sodium chloride
in the diet and showed no signs of subclinical
hyponatremia or hypokalemia (Ermon et al.,
2014). More recently, Frank and colleagues
examined correlations of electrolytes to muscle
creatine kinase (CK) 2 days into a race and
found that the declines in potassium and
sodium were both correlated to a CK rise, sug-
gesting that hypokalemia is associated with
muscle cell permeability (Frank et al., 2015).
These findings do not warrant use of electrolyte

mixtures to sustain dogs who are eating com-

mercial rations as these studies are in dogs

being fed large amounts of meat, which is low

in sodium and potassium compared to their

normal training rations. Currently studies

using electrolyte mixtures have shown no ben-

eficial effects and/or potential gastrointestinal

upset (diarrhea) after a day of activity (Young et

al., 1960; Mazin et al., 2001). Most importantly, if

sufficient commercial dog food formulated

according to the Association of American Feed

Controls Officials (AAFCO) regulations is pro-

vided, supplementation with any of these major

minerals is not necessary; however, it should be

noted that calcium availability will be hindered

when providing fat at over 60% of the ME in a

feed. Competitions where aggressive fat supple-

mentation is used are usually a few days to a

week in duration and should not affect long‐term

calcium homeostasis.

Trace mineral intake (see Table  4.3) will

increase proportionally with intake of commer-

cial dog food and will also increase to a lesser

degree when using meat to supplement com-

mercial diets. To date there has not been an

observed clinical deficiency in copper, zinc,

iron, manganese, iodine, or selenium in athletic

canines being fed traditional commercial or

commercial dog food/meat mix diets. This is

likely due to the amounts of trace minerals

incorporated into most pet foods being greater

than the minimum amount legislated by

AAFCO, and the increased intake of food in

athletic dogs. Currently, it is unknown whether

supplemental trace minerals are needed, or if

the amounts deemed sufficient for pet dogs will

meet the demands of performance canids.

Vitamins/antioxidants and the

canine athlete

Vitamins are classified as either fat‐ or water‐

soluble (Table  4.4). Water‐soluble vitamins are

involved in metabolism as intermediates and

coenzymes within the citric acid cycle or as car-

riers and coenzymes for carbon transfer.

Sufficiency in these vitamins is absolutely

required for metabolism. Many commercial dog

foods and meats tend to be fairly rich in these

vitamins. Most commercial pet food will con-

tain two to ten times the minimum requirement

Table 4.3 Essential major and trace minerals

Major minerals Trace minerals

Potassium

Calcium

Phosphorus

Sodium

Chloride

Magnesium

Iron

Zinc

Copper

Manganese

Iodine

Selenium