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  • Author or Editor: Donald E. Spiers x
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Abstract

Objective—To determine whether cattle exposed to heat stress alone or heat stress while consuming endophyte-infected fescue (EIF) have lower wholeblood (WB) concentrations of glutathione (GSH).

Animals—10 Simmental cows.

Procedure—Cows were sequentially exposed to thermoneutral (TN; 2 weeks; 18 C, 50% relative humidity [RH]), heat stress (HS; 2 weeks; alternating 4-hour intervals at 26 and 33 C; 50% RH), and heat stress while consuming EIF (10 µg of ergovaline/kg/d; 2 weeks; HS + EIF). Blood samples were collected after each period and tested for GSH and oxidized glutathione (GSSG) concentrations.

Results—Feed consumption was similar when data were analyzed for time points at which WB concentrations of GSH or GSSG were determined. However, significant effects of treatment, cow, days exposed to heat, cow-by-treatment interaction, and treatment-bydays exposed to heat interaction were detected when data were considered simultaneously. Mean ± SD hematocrit for TN, HS, and HS + EIF were 35.3 ± 3, 33.3 ± 2, and 37.1 ± 3%, respectively. Mean WBGSH concentrations for TN, HS, and HS + EIF were 3.2 ± 0.65, 2.7 ± 0.62, and 2.4 ± 0.56 mmol/L of RBC, respectively. Reduced WBGSH concentrations were associated with reduced feed intake during the later part of each heat period.

Conclusion and Clinical Relevance—Decreased GSH and increased GSSG concentrations were evident during heat stress, especially when cattle consumed EIF. These were associated with reduced feed intake during heat stress. Heat stress, reductions in feed intake, and thermoregulatory effects of EIF may induce oxidative stress in cattle. (Am J Vet Res 2002;63:799–803)

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in American Journal of Veterinary Research

Abstract

Objective—To compare effects of a commercially available omeprazole paste and a compounded omeprazole suspension on healing of gastric ulcers in Thoroughbred racehorses in active training.

Design—Randomized controlled trial.

Animals—32 horses with gastric ulcers.

Procedure—Horses were assigned to 2 groups on the basis of endoscopic gastric ulcer severity. Group-1 horses were treated with omeprazole suspension for 30 days and with omeprazole paste for an additional 30 days. Group-2 horses were treated with omeprazole paste for 30 days and omeprazole suspension for an additional 30 days. Serum omeprazole concentrations were measured in 4 additional healthy horses after administration of a single dose of each formulation. In all instances, omeprazole was administered at a dose of 4 mg/kg (1.8 mg/lb), PO.

Results—Ulcer severity scores on day 0 were not significantly different between groups. On day 30, ulcer severity score was significantly decreased, compared with day-0 score, in group-2 but not in group-1 horses. On day 60, ulcer severity score was significantly decreased, compared with day-0 and day-30 scores, in group-1 horses. In group-2 horses, ulcer severity score on day 60 was significantly lower than the day-0 score but was not significantly different from the day-30 score. Maximum observed serum omeprazole concentration and area under the concentration-time curve were significantly higher after administration of the paste versus the suspension formulation.

Conclusions and Clinical Relevance—Results suggest that although administration of the commercially available paste omeprazole formulation was effective in promoting healing of gastric ulcers in these horses, administration of the compounded omeprazole suspension was ineffective. (J Am Vet Med Assoc 2002;221:1139–1143)

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in Journal of the American Veterinary Medical Association