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Dirikolu L, Waller P, Malveaux K, Lucas CH, Lomnicka I, Pourciau A, Bennadji H, Liu CC. Total Carbon Dioxide (TCO 2) Concentrations in Thoroughbred and Quarter Racehorses in Louisiana. J Equine Vet Sci 2023; 121:104220. [PMID: 36621701 DOI: 10.1016/j.jevs.2023.104220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/03/2023] [Accepted: 01/03/2023] [Indexed: 01/09/2023]
Abstract
The TCO2 (total carbon dioxide) test is performed on the blood of racehorses as a means of combatting the practice of administering alkalizing agents. This study evaluated serum TCO2 concentrations and factors influencing concentration of TCO2 in Thoroughbred and Quarter Horses. The normality of data were evaluated with a Shapiro-Wilk test. Mann-Whitney tests and Kruskal-Wallis tests were used against different effects. When a fixed effect was detected, Dunn's post-hoc comparisons were performed. The median pre-race serum TCO2 concentration (32.20 mmol/L (interquartile range (IQR): 30.80-33.50)) was higher than that of post-race samples (26.70 mmol/L (IQR: 24.55-29.25)) (P < .0001). The median TCO2 concentrations in pre-race samples were different between Thoroughbred (32.40 mmol/L (IQR: 30.90-33.60)) and Quarter Horses (31.30 mmol/L (IQR: 30.00-32.50)) (P < .0001). The median pre-race TCO2 concentrations were 32.75 (IQR: 31.40-33.90), 31.40 (IQR: 29.80-32.80), 32.50 (IQR: 31.20-33.88), and 31.60 (IQR 30.00-32.70) mmol/L in racehorses at Fair Grounds, Louisiana Downs, Delta Downs, and Evangeline Downs racetracks, respectively (P < .0001). The total serum TCO2 concentrations in Thoroughbred and Quarter Horse racehorses were affected by seasonal temperature variation (P < .0001). A smaller sample size was available for post-race samples (n = 205) and Quarter Horse pre-race samples (n = 351). The results of this study indicated that the breed, seasonal temperature variation, pre-race or post-race sampling, and track location are strongly correlated to total TCO2 concentrations. It was not clear whether the statistically significant differences in TCO2 levels among racetracks in Louisiana were due to location of racetracks and/or seasonal temperature variation.
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Affiliation(s)
- Levent Dirikolu
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA.
| | - Pamela Waller
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Kesha Malveaux
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Cam H Lucas
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Izabela Lomnicka
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Ashley Pourciau
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Hayat Bennadji
- Equine Medication Surveillance Laboratory, Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
| | - Chin-Chi Liu
- Department of Veterinary Clinical Services, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
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Lindinger MI. Total Carbon Dioxide in Adult Standardbred and Thoroughbred Horses. J Equine Vet Sci 2021; 106:103730. [PMID: 34670689 DOI: 10.1016/j.jevs.2021.103730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/02/2021] [Accepted: 08/08/2021] [Indexed: 10/20/2022]
Abstract
The TCO2 (total carbon dioxide) test is performed on the blood of racehorses as a means of combatting the practice of administering alkalizing agents for the purpose of enhancing performance. The purposes of this review are to present an overview of the factors contributing to TCO2 and to review the literature regarding TCO2 in adult Standardbred and Thoroughbred horses to demonstrate the range of variability of TCO2 in horses. Most of the research published on the topic of TCO2 or bicarbonate measurement in racehorses was accessed and reviewed. PubMed and Google Scholar were the primary search engines used to source the relevant literature. The main physicochemical factors that contribute to changes in TCO2 in horses at rest are changes in strong ions concentration, followed by changes in weak acid (i.e. plasma albumin) concentrations. There is a wide normal distribution of TCO2 in horses ranging from 23 mmol/L to 38 mmol/L. Independent of administration of alkalizing agents, blood TCO2 is affected mainly by feeding, time of day (diurnal variation), season and exercise. There are few studies that have reported hour-by-hour changes in TCO2. Racehorse population studies suffer from lack of validation regarding whether or not a horse was administered an alkalizing agent. It is concluded that the normal range of TCO2 in non-alkalized Standardbred and Thoroughbred horses is significantly wider than has been appreciated, that periods of elevated TCO2 appear to be normal for many horses at rest, and that a TCO2 test alone is not definitive for the purposes of determining of an alkalizing agent has been administered to a horse.
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