Field study of the effect of an anionic supplement on the incidence of hypocalcemia, clinical disease, production, and reproduction in early lactation in dairy herds
Bibliographic record
Abstract
This thesis is an investigation of the effect of a prepartum negative dietary cation-anion difference (DCAD) diet on postpartum health, immune function, production, and reproductive performance, as well as culling risk in dairy herds. The main study was a randomized clinical trial of a negative DCAD diet, including more than 1000 cows from 4 commercial farms. Close-up pens with cows 3 wk before calving were randomly assigned to a negative DCAD (TRT; -108 mEq/kg dry matter [DM]) or a control diet (+105 mEq/kg DM with a placebo supplement). The outcomes include blood Ca concentrations, neutrophil function, postpartum disease, milk production, reproductive performance, and culling. Additionally, the diagnostic accuracy of a point-of-care blood calcium meter was evaluated. We observed a significant reduction in milk fever incidence in over-conditioned multiparous cows fed TRT. In multiparous cows, the prevalence of subclinical hypocalcemia (tCa ≤ 2.14 mmol/L) in the first 2 days in milk (DIM) was lower when fed TRT, with no differences in primiparous cows. Multiparous cows fed TRT were less likely to have more than one disease in the postpartum period, which might have contributed to the tendency of reduced risk of leaving the herd by 30 DIM, and a reduced culling risk over the whole lactation. There was a significant reduction in displaced abomasum and a tendency for lower odds of clinical mastitis within 30 DIM in TRT. Contrary to our hypothesis, peripartum neutrophil killing activity was not enhanced in healthy multiparous cows by feeding TRT. Under commercial conditions, the negative DCAD diet resulted in increased milk yield in early lactation, better reproductive performance, and reduced culling rate in multiparous cows. In primiparous cows, there were no treatment effects on milk production or culling, but treatment was detrimental for pregnancy rate. The meter assessment revealed that when used with fresh plasma, which requires additional sample preparation, the device showed some potential to classify cows as hypocalcemic, but overall its diagnostic accuracy was fair to low. Our results suggest that a negative DCAD diet in the close-up dry period should be targeted to multiparous cows, where we observed health and performance benefits.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".