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  • Author or Editor: Deborah A. Sundstrom x
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Abstract

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 different.

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)

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in American Journal of Veterinary Research

Abstract

Objective—To determine effects of increased dietary protein and decreased dietary carbohydrate on hematologic variables, body composition, and racing performance in Greyhounds.

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)

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in American Journal of Veterinary Research

Abstract

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)

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in American Journal of Veterinary Research

Abstract

Objectives—To determine maintenance energy requirements and effect of diet on performance of racing Greyhounds.

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)

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in American Journal of Veterinary Research

Abstract

Objectives—To determine the effects of racing and training on serum thyroxine (T4), triiodothyronine (T3), and thyroid stimulating hormone (TSH) concentrations in Greyhounds.

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 other breeds.

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 Res 2001;62:1969–1972)

Full access
in American Journal of Veterinary Research