Factors contributing to plasma TCO <sub>2</sub> and acid‐base state in Ontario Standardbred racehorses
Bibliographic record
Abstract
REASONS FOR PERFORMING STUDY: 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. OBJECTIVES: 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. MATERIALS AND 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).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".