Metabolic parameters in transition cows as indicators for early-lactation culling risk
Bibliographic record
Abstract
A retrospective cohort study was performed with the objective of determining whether the serum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), or calcium were associated with the risk of culling within 60 d in milk (DIM) in Holstein cows, and to establish thresholds for each metabolite that were predictive of increased culling risk. Data from 5,979 cows in Ontario (Canada) and several US states were obtained from 4 previously reported studies. For each metabolite and each of 3 sampling weeks (-1, +1, and +2 relative to calving), an optimal threshold was calculated based on having the maximum combined sensitivity (Se) and specificity (Sp) and used to categorize the serum concentrations into high and low risk groups. Logistic regression models were built for each metabolite and each week of sampling, as well as considering together all metabolites in wk -1 and wk +1 relative to calving. Cow was considered the experimental unit and herd as a random effect. Considered separately, precalving NEFA ≥ 0.4 mmol/L [odds ratio (OR)=1.8; 95% confidence interval (CI)=1.4 to 2.2], NEFA ≥ 0.8 mmol/L in wk +1 relative to calving (OR=2.0; 95% CI=1.5 to 2.6) and NEFA ≥ 0.8 mmol/L in wk +2 (OR=4.2; 95% CI=1.9 to 9.4 for cows in lactation 2; OR=2.1; 95% CI=1.4 to 3.3 for cows in lactation ≥ 3) were each associated with an increased risk of culling within the first 60 DIM. Similarly, BHBA ≥ 0.7 mmol/L in wk -1 (OR=1.8; 95% CI=1.3 to 2.5), BHBA ≥ 1.2 mmol/L in wk +1 (OR=1.8; 95% CI=1.4 to 2.2), and BHBA ≥ 1.6 mmol/L in wk +2 (OR=3.2; 95% CI=1.6 to 6.4 for cows in lactation 2; OR=2.3; 95% CI=1.6 to 3.3 for cows in lactation ≥ 3) were each associated with an increased risk of culling within the first 60 DIM. Likewise, calcium ≤ 2.3 mmol/L in wk -1 (OR=1.6; 95% CI=1.2 to 2.2), calcium ≤ 2.2 mmol/L in wk +1 (OR=1.5; 95% CI=1.2 to 1.9), and calcium ≤ 2.3 mmol/L in wk +2 (OR=2.3; 95% CI=1.1 to 3.1) were each associated with an increased risk of culling within the first 60 DIM. When all metabolites were analyzed together, serum NEFA and calcium concentrations in wk -1 and serum NEFA concentration in wk +1 remained in the models. In conclusion, elevated serum NEFA and BHBA concentrations and lower serum calcium concentrations within 1 wk before calving through 2 wk after calving were associated with an increased risk of culling in early lactation. Measuring the concentration of selected metabolites around parturition may help to develop monitoring and intervention strategies to prevent early culling in transition dairy cows.
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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 | 0.001 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".