Objectives—To determine effect of α-tocopherol
supplementation on serum vitamin E concentrations
in Greyhounds before and after a race.
Animals—8 adult racing Greyhounds.
Procedure—Dogs were given 2 capsules of α-tocopheryl
acetate (total, 680 units [0.5 g]) with food that
contained ≤ 15 mg of vitamin E/kg each morning for 7
days. Dogs were exercised in a 30 × 30-m grass paddock
for 15 minutes twice a day and raced for 500 m
twice a week. Blood samples were collected before
and 5 minutes after a race, before supplementation
was begun, and after 7 days of supplementation.
Blood and diet samples were analyzed for tocopherols
and α-tocopheryl acetate.
Results—Before supplementation, serum α-tocopherol
concentration after racing (mean ± SD,
6.7 ± 2.4 mg/L ) was significantly lower than before
racing (12.2 ± 3.1 mg/L). After supplementation, α-
tocopherol concentrations were significantly higher
overall, although values obtained before (26.6 ± 5.2
mg/L) and after (29.8 ± 3.6 mg/L) racing were not significantly
Conclusions and Clinical Relevance—Supplementation
with α-tocopheryl acetate increased serum
α-tocopherol concentrations and eliminated the
decrease in α-tocopherol concentration that was
detected after a race, which may decrease oxidation
during exercise and improve performance or recovery.
(Am J Vet Res 2001;62:1118–1120)
Objective—To determine effects of increased dietary
protein and decreased dietary carbohydrate on hematologic
variables, body composition, and racing performance
Animals—8 adult Greyhounds.
Procedure—Dogs were fed a high-protein (HP; 37%
metabolizable-energy [ME] protein, 33% ME fat, 30%
ME carbohydrate) or moderate-protein (MP; 24% ME
protein, 33% ME fat, 43% ME carbohydrate) extruded
diet for 11 weeks. Dogs subsequently were fed
the other diet for 11 weeks (crossover design). Dogs
raced a distance of 500 m twice weekly. Rectal temperature,
hematologic variables before and after racing,
plasma volume, total body water, body weight,
average weekly food intake, and race times were
measured at the end of each diet period.
Results—When dogs were fed the MP diet, compared
with the HP diet, values (mean ± SD) differed
significantly for race time (32.43 ± 0.48 vs 32.61 ±
0.50 seconds), body weight (32.8 ± 2.5 vs 32.2 ± 2.9
kg), Hct before (56 ± 4 vs 54 ± 6%) and after (67 ± 3
vs 64 ± 8%) racing, and glucose (131 ± 16 vs 151 ±
27 mg/dl) and triglyceride (128 ± 17 vs 104 ± 28
mg/dl) concentrations after racing.
Conclusions and Clinical Relevance—Greyhounds
were 0.18 seconds slower (equivalent to 0.08 m/s or
2.6 m) over a distance of 500 m when fed a diet with
increased protein and decreased carbohydrate.
Improved performance attributed to feeding meat to
racing Greyhounds apparently is not attributable to
increased dietary protein and decreased dietary carbohydrate.
(Am J Vet Res 2001;62:440–447)
Objective—To determine whether mild restriction of
food intake affects clinicopathologic variables, body
composition, and performance of dogs undertaking
intense sprint exercise.
Animals—9 trained healthy adult Greyhounds.
Procedure—Dogs were offered food free choice
once daily for 9 weeks until body weight and food
intake stabilized. Dogs were then randomly assigned
to be fed either 85% or 100% of this quantity of food
in a crossover study (duration of each diet treatment
period, 9 weeks). Dogs raced a distance of 500 m
twice weekly. Clinicopathologic variables were
assessed before and 5 minutes after racing; food
intake, weight, body composition, body condition
score, and race times were compared at the end of
each diet period.
Results—Compared with values associated with
unrestricted access to food, there were significant
decreases in mean body weight (by 6%) and median
body condition score (from 3.75 to 3.5 on a 9-point
scale) and the mean speed of the dogs was significantly
faster (by 0.7 km/h) when food intake was
restricted. Body composition and most clinicopathologic
variables were unaffected by diet treatment, but
dogs given restricted access to food had slightly
fewer neutrophils, compared with values determined
when food intake was unrestricted.
Conclusions and Clinical Relevance—Results indicate
that the common practice among Greyhound
trainers of mildly restricting food intake of racing dogs
to reduce body weight does improve sprint performance.
A body condition score of approximately 3.5
on a 9-point scale is normal for a trained Greyhound in
racing condition. (Am J Vet Res 2005;66:1065–1070)
Objectives—To determine maintenance energy
requirements and effect of diet on performance of
Animals—7 adult racing Greyhounds.
Procedure—Dogs were fed a higher fat and protein
(HFP) or a lower fat and protein (LFP) diet for 8 weeks
in a crossover design. Dogs were exercised for 15
minutes twice daily in a paddock and raced 500 m
twice weekly. Blood gas, hematologic, and serum biochemical
analyses were performed before and after
racing, and race times were compared at the end of
each diet period.
Results—Mean race time was significantly shorter
(32.81± 0.65 seconds vs 33.05 ± 0.71 seconds), and
mean racing speed over 500 m was significantly
faster (15.25 ± 0.30 vs 15.13 ± 0.30 m·s–1) when dogs
were fed the HFP diet than when they were fed the
LFP diet. Diet had little or no effect on results of blood
gas, hematologic, and serum biochemical analyses,
except that Hct was 4% greater before and after racing
when the HFP diet was fed than when the LFP
diet was fed. Mean SD metabolizable energy intake
from weeks 1 through 16 was 155 ± 9 kcal·kg–0.75·d–1.
Conclusions and Clinical Relevance—Racing
Greyhounds ran faster when fed a diet containing
higher fat and protein and lower carbohydrate contents.
Their maintenance metabolizable energy
requirement was slightly higher than that of moderately
active dogs. (Am J Vet Res 2000;61:1566–1573)
Objectives—To determine the effects of racing and
training on serum thyroxine (T4), triiodothyronine (T3),
and thyroid stimulating hormone (TSH) concentrations
Animals—9 adult racing Greyhounds.
Procedure—Serum thyroid hormone concentrations
were measured before and 5 minutes after a race in
dogs trained to race 500m twice weekly for 6 months.
Resting concentrations were measured again when
these dogs had been neutered and had not raced for
3 months. Postrace concentrations were adjusted relative
to albumin concentration to allow for effects of
hemoconcentration. Thyroid hormone concentrations
were then compared with those of clinically normal
dogs of non-Greyhound breeds.
Results—When adjusted for hemoconcentration,
total T4 concentrations increased significantly after
racing and TSH concentrations decreased; however,
there was no evidence of a change in free T4 or total
or free T3 concentrations. Resting total T4 concentrations
increased significantly when dogs had been
neutered and were not in training. There was no evidence
that training and neutering affected resting
TSH, total or free T3, or free T4 concentrations.
Resting concentrations of T3, TSH, and autoantibodies
against T4, T3, and thyroglobulin were similar to those
found in other breeds; however, resting free and total
T4 concentrations were lower than those found in
Conclusions and Clinical Relevance—Except for
total T4, thyroid hormone concentrations in
Greyhounds are affected little by sprint racing and
training. Greyhounds with low resting total and free T4
concentrations may not be hypothyroid. (Am J Vet