Equine veterinary journal. Supplement2011; (38); 592-600; doi: 10.1111/j.2042-3306.2010.00249.x

Factors contributing to plasma TCO2 and acid-base state in Ontario Standardbred racehorses.

Waller, AP
·
Pearson, W
·
Lindinger, MI

Abstract: Standardbred and Thoroughbred racehorses around the world are tested for performance enhancing substances. Among these are blood alkalising substances that raise plasma pH and total carbon dioxide (TCO(2)) concentration. However, many horses have an elevated TCO(2) due to dietary, environmental and health concerns without having been administered an alkalising substance. Objective: The purposes of this study were to determine the acid-base profile of a cross section of Standardbred horses in racing/race training in Ontario and the main independent variables that contributed to acid-base state. Methods: On nonracing days, blood from 211 horses at rest, from 9 training facilities, was analysed within 30 min for plasma pH (7.406 ± 0.039; mean ± s.e.), PCO(2) (50.0 ± 3.4 mmHg), from which [HCO(3)(-)] (31.2 ± 2.8 mmol/l) and [TCO(2)] (33.1 ± 2.9 mmol/l; range 25.66-42.9) were calculated. From these, a subset of 161 horses had full data sets for plasma protein and strong ion concentrations. These data were further analysed by facility and level of TCO(2). Data on nutrition, training, racing and medications were also collected. Results: There were significant differences amongst facilities with respect to plasma pH, TCO(2), strong ion difference ([SID]), PCO(2) and total weak acid concentration ([A(tot)]). Horses having the highest TCO(2) (37.0-42.9 mmol/l, n = 16) had significantly higher [SID] (52.9 ± 0.8 mEq/l) and PCO(2) (52.5 ± 0.7 mmHg) and relatively low [A(tot)] (14.9 ± 0.7 mEq/l) compared to average TCO(2) (32.1.0-34.9 mmol/l) horses (n = 75). In horses with the lowest TCO(2) (n = 11) the greatest contributor was elevated [A(tot) ] (21.0 ± 0.7 mEq/l) and unmeasured (acetate, citrate, proprionate, butyrate) weak acids (7.0 ± 0.2 mEq/l) while [SID] (49.6 ± 0.8 mEq/l) and PCO(2) (47.8 ± 1.0 mmHg) were similar to average TCO(2) horses. Thirty-two horses had a TCO(2) ranging from 35.0-36.9 mmol/l). Conclusions: There is a wide range of acid-base state and factors contributing to acid-base state amongst Standardbred race horses in Ontario. Dietary, environmental and handling practices and health concerns, that elevate plasma [SID], lower [A(tot)] and lower the concentration of unmeasured weak acids are the primary contributors to alkalosis and elevated TCO(2).

Get Full Text

Publication Date: 2011-05-27 PubMed ID: 21059066DOI: 10.1111/j.2042-3306.2010.00249.xGoogle Scholar: Lookup

The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.

Facebook X LinkedIn Email Copy

Summary
Cite This
Publication
Affiliations
MeSH
Citations

Journal Article
Research Support
Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research evaluated factors leading to variations in total carbon dioxide (TCO2) and acid-base balance in Standardbred racehorses in Ontario. The study sought to understand causes other than the administration of blood alkalising substances, such as dietary, environmental, and health factors, that could affect these parameters.

Research Methods

The study involved observing and analyzing blood samples from 211 Standardbred horses at rest on non-racing days from nine training facilities in Ontario. The analysis focused on plasma pH, CO2 partial pressure (PCO(2)), bicarbonate concentration ([HCO(3) (-)]) and total carbon dioxide concentration ([TCO2]).
From the initial 211 horses, a subset of 161 horses was further investigated for plasma protein and strong ion concentrations. The data were scrutinized depending on the facility and level of TCO2 in the horses.
The research team also collected data about nutrition, training routines, racing schedules, and medication records for the participating horses.

Research Findings

The study found significant differences among training facilities regarding plasma pH, TCO2, strong ion difference ([SID]), PCO(2), and total weak acid concentration ([A(tot)]).
Horses with higher levels of TCO2 were also found to have significantly elevated [SID] and PCO2, and relatively low [A(tot)], compared to horses with average TCO2 levels.
In contrast, the primary contributor in horses with the lowest TCO2 levels was raised [A(tot)] and unmeasured weak acids, such as acetate, citrate, propionate, and butyrate.
[SID] and PCO2 levels were found to be similar in horses with average and low TCO2 levels.

Conclusions

The research concluded that a wide range of acid-base states and contributing factors exist among Standardbred racehorses in Ontario.
Major factors that contribute to alkalosis and elevated TCO2 are dietary, environmental, and handling practices, along with health issues that increase plasma [SID], decrease [A(tot)], and lower the concentration of unmeasured weak acids.

Cite This Article

APA

Waller AP, Pearson W, Lindinger MI. (2011). Factors contributing to plasma TCO2 and acid-base state in Ontario Standardbred racehorses. Equine Vet J Suppl(38), 592-600. https://doi.org/10.1111/j.2042-3306.2010.00249.x