Reference Values and Association of Body Weight, Age, and Sex With Echocardiographic Measurements in Non-Athletic Quarter Horses
Bibliographic record
Abstract
BACKGROUND: Echocardiographic reference intervals for Quarter Horses are infrequently reported. OBJECTIVES: To provide standard echocardiographic measurements for sedentary Quarter Horses and evaluate the relationship between physical characteristics (body weight, age, sex) and echocardiographic measurements. ANIMALS: Forty-one sedentary Quarter Horses, free of cardiac disease, from a university research herd. METHODS: A cross-sectional study evaluating standardized echocardiograms performed on sedentary Quarter Horses (41) between 2020 and 2022. Reference intervals were calculated for raw and weight-corrected values. Multiple linear regression was performed to evaluate the relationship between the physical characteristics (body weight, age, sex) and echocardiographic variables. RESULTS: Multiple linear regression showed that every 100 kg of body weight was associated with a 3 (95% CI 1-6) mm thicker left ventricular free wall in systole (p = 0.02), an 8 (95% CI 2-13) mm larger left atrial diameter (p < 0.01), and a 4 (95% CI 0-9) mm larger pulmonary artery diameter (p = 0.04). Every year in age was associated with a 0 (95% CI 0-1) mm larger left atrial diameter (p = 0.02), a 0 (95% CI 0-1) mm larger aortic diameter (p = 0.01), and a 0 (95% CI 0-1) mm larger pulmonary artery diameter (p = 0.01). Left atrial to left ventricular ratio was 1 (95% CI -1 to 0) mm smaller in geldings compared to mares (p = 0.03). CONCLUSIONS AND CLINICAL IMPORTANCE: This study provides echocardiographic reference intervals for a cohort of sedentary Quarter Horses and clarifies the association with body weight, age, and sex with these variables.
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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 | 0.002 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| 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".