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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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Bergstrom B, Foreman J, Foreman C, Barger A. Intra- and inter-day variability in plasma tCO 2 concentration in sedentary horses. COMPARATIVE EXERCISE PHYSIOLOGY 2014. [DOI: 10.3920/cep13027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sodium bicarbonate and other alkalinising solutions (‘milkshakes’) have been given to horses surreptitiously before exercise to provide exogenous buffering effects. After an initial positive blood test, some accused horse trainers claim that their horses ‘naturally test high’, so some jurisdictions allow a secured quarantine in which the horse is tested multiple times. The objective of this experiment was to determine the intra- and inter-day variability of plasma total CO2 (tCO2) and other plasma strong ions in a group of sedentary horses housed similarly to a quarantine period. The hypothesis was that plasma tCO2 would not remain constant over a multi-day monitoring interval, but would vary measurably during that interval. Eight sedentary (unconditioned) horses were studied for 2 weeks. Horses were acclimated to a climate-controlled indoor environment and an alfalfa-only diet for a minimum of 10 days prior to sampling. Horses were sampled 3 times daily for 5 consecutive days at 7:00, 11:00 and 15:00 h. Blood samples were collected directly into 10 ml heparinised evacuated glass tubes by jugular venipuncture using a double-ended 0.91 mm needle. Samples were chilled until concentrations of plasma tCO2, Na+, K+, and Cl-, were determined within 1-3 h of sampling using an automated serum chemistry analyzer which was calibrated daily using commercial reagents obtained from the manufacturer as well as externally-obtained NIST-traceable calibrating solutions. Mean results documented mild variations in mean plasma tCO2 (range 28.9-31.6 mmol/l), but individual horses’ plasma tCO2 ranged over 4-7 units. Results showed that there was considerable intra- and inter-individual variability in plasma tCO2. Mean pooled tCO2 and measured strong ion difference (SIDm) differed by time-of-day, with both late morning and early afternoon values lower than early morning values (P<0.001). There was a strong positive linear relationship between plasma SIDm and tCO2 (r=0.75, P<0.001).
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Affiliation(s)
- B.E. Bergstrom
- College of Veterinary Medicine, Department of Veterinary Clinical Medicine, University of Illinois, 1008 West Hazelwood Drive, Urbana, IL 61802, USA
| | - J.H. Foreman
- College of Veterinary Medicine, Department of Veterinary Clinical Medicine, University of Illinois, 1008 West Hazelwood Drive, Urbana, IL 61802, USA
| | - C.R. Foreman
- College of Veterinary Medicine, Department of Veterinary Clinical Medicine, University of Illinois, 1008 West Hazelwood Drive, Urbana, IL 61802, USA
| | - A.M. Barger
- College of Veterinary Medicine, Department of Veterinary Clinical Pathobiology, University of Illinois, 1008 West Hazelwood Drive, Urbana, IL 61802, USA
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Lindinger MI, Ecker GL. Gastric emptying, intestinal absorption of electrolytes and exercise performance in electrolyte-supplemented horses. Exp Physiol 2012; 98:193-206. [DOI: 10.1113/expphysiol.2012.065185] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Odongo NE, Greenwood SL, Or-Rashid MM, Radford D, AlZahal O, Shoveller AK, Lindinger MI, Matthews JC, McBride BW. Effects of nutritionally induced metabolic acidosis with or without glutamine infusion on acid-base balance, plasma amino acids, and plasma nonesterified fatty acids in sheep1. J Anim Sci 2009; 87:1077-84. [DOI: 10.2527/jas.2008-1165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Electrolyte supplementation after prolonged moderate-intensity exercise results in decreased plasma [TCO2] in Standardbreds. ACTA ACUST UNITED AC 2007. [DOI: 10.1017/s1478061507890086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThe present study used the physicochemical approach to characterize the changes in acid–base status that occur in Standardbreds after post-exercise electrolyte supplementation. Jugular venous blood was sampled from six conditioned Standardbreds on two separate occasions, at rest and for 24 h following a competitive exercise test (CET) designed to simulate the speed and endurance test of a 3-day event. After the CETs, horses were given water ad libitum and either a hypotonic commercial electrolyte solution, via nasogastric tube followed by a typical hay/grain meal, or a hay/grain meal alone. The electrolyte supplementation resulted in c. 2 mmol l− 1 decreased plasma [TCO2] during the recovery period as compared with control. The primary contributor to the decreased [TCO2] with electrolyte supplementation was a decreased strong ion difference ([SID]), as a result of the non-significant increase in plasma [Cl− ]. Additionally, electrolyte supplementation resulted in faster restoration of hydration status compared with control, as evidenced by faster recovery of plasma [protein] and total weak acid concentration ([Atot]). It is concluded that oral administration of a hypotonic electrolyte solution after prolonged moderate-intensity exercise diminishes the post-exercise alkalosis, and that recovery of hydration status is still incomplete 24 h after exercise when no electrolytes are given. Thus, supplementation with electrolytes according to estimated sweat losses may attenuate post-exercise increases in plasma [TCO2], which is of significant practical interest to the horse racing community, as a testing threshold of greater than 37 mmol l− 1 is used by many racing jurisdictions to determine whether a horse has been administered an alkalinizing agent.
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Las JE, Odongo NE, Lindinger MI, AlZahal O, Shoveller AK, Matthews JC, McBride BW. Effects of dietary strong acid anion challenge on regulation of acid-base balance in sheep1. J Anim Sci 2007; 85:2222-9. [PMID: 17504956 DOI: 10.2527/jas.2007-0036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The acid-base status of the extracellular fluid is directly affected by the concentrations of strong basic cations and strong acid anions that are absorbed into the bloodstream from the diet. The objective of this study was to develop and characterize a model for dietary acid challenge in sheep by decreasing the dietary cation-anion difference (DCAD) using NutriChlor (HCl-treated canola meal), an anionic feed supplement. Ten fully fleeced sheep (Rideau-Arcott, 54.3 +/- 6.7 kg of BW) were fed either a control supplement [200 g/d of canola meal, DCAD = 184 mEq/kg of DM, calculated as (Na+ + K+) - (Cl- + S2-)] or an anionic supplement (AS; 200 g/d of NutriChlor, DCAD = -206 mEq/kg of DM) offered twice daily at 0700 and 1100 in a randomized complete block design. The sheep were individually housed and limit-fed a basal diet of dehydrated alfalfa pellets (22% CP and 1.2 Mcal of NE(g)/kg, DM basis) at 1.1 kg of DM/d offered twice daily at 1000 and 1300. Two days before the beginning of the experiment, the sheep were fitted with vinyl catheters (0.86-mm i.d., 1.32-mm o.d.) in the left jugular vein to facilitate blood sampling. Blood and urine samples were obtained daily from 1100 to 1130 on d 1 through 9 and at 0700, 1000, 1300, 1600, and 1900 on d 10. Blood was analyzed for hematocrit, plasma pH, gases, strong ions, and total protein. Urine samples were analyzed for pH. The AS induced a nonrespiratory acid-base disturbance associated with lower (P < 0.05) plasma pH (7.47 vs. 7.39), lower (P < 0.05) urine pH (8.13 vs. 6.09), and lower (P < 0.05) strong ion difference (42.5 vs. 39.5). The AS reduced (P < 0.05) the concentration of plasma glucose, base excess, and bicarbonate and increased (P < 0.05) the concentration of K+ and Cl-. Lowering DCAD increased (P < 0.05) Ca2+ concentrations in plasma by 13%. In conclusion, this dietary model successfully induced a significant acid-base disturbance in sheep. Although the acidifying effects of negative DCAD in the diet may have short-term prophylactic effects of elevating the concentration of Ca2+ in plasma, negative DCAD may have detrimental effects on acid-base balance.
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Affiliation(s)
- J E Las
- Department of Animal and Poultry Science, University of Guelph, Ontario, Canada, N1G 2W1
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