Impact of postpartum milking frequency on the immune system and the blood metabolite concentration of dairy cows
Bibliographic record
Abstract
The transition from pregnancy to lactation is marked by metabolic, hormonal, and immunological changes that have an impact on the incidence of infectious and metabolic diseases. The aim of this study was to evaluate the effect on immune function and blood metabolite concentration of limiting milk production in early lactation to reduce negative energy balance. Twenty-two multiparous Holstein cows were milked either once a day (1x) or twice a day (2x) for the first week postpartum. All cows were milked twice daily for the rest of lactation. Blood concentrations of nonesterified fatty acids (NEFA), beta-hydroxybutyric acid (BHBA), calcium, bilirubin, urea, phosphorus, glucose, leptin, stanniocalcin-1, and 17beta-estradiol were determined in samples collected from 5 wk before scheduled calving to 5 wk after calving. Polymorphonuclear leukocytes (PMNL) were isolated from blood to conduct assays for chemotaxis, phagocytosis, and respiratory burst. Peripheral blood mononuclear cells (PBMC) were isolated to evaluate lymphocyte proliferation and cytokine production (tumor necrosis factor-alpha, IL-4, and interferon-gamma). Cows milked 1x produced 31% less milk than cows milked 2x during the first week of lactation. Over the following 13 wk of lactation, the milk production of cows milked 1x during the first week was 8.1% lower than for cows milked 2x. However, because the percentages of fat and protein were greater in the milk from 1x cows, the yields of milk components and energy-corrected milk were similar. Calving induced an increase in the concentrations of NEFA, BHBA, urea, and bilirubin. The increases in levels of NEFA and BHBA were greater in cows milked 2x than in cows milked 1x. During the same period, the serum glucose concentration decreased but remained greater in cows milked 1x. Serum calcium on d 4 and serum phosphorus on d 4 and 5 were greater in cows milked 1x. The differences between the 2 groups persisted beyond treatment until postpartum d 24 for NEFA and glucose and until postpartum d 14 for BHBA. After calving, the concentrations of leptin and stanniocalcin-1 decreased. During the first week postpartum, the decrease of leptin was less marked in cows milked 1x. The immune functions of PBMC and PMNL isolated from experimental cows and incubated using a standard medium did not show clear-cut peripartum immunosuppression. These variables were not significantly affected by the treatments, with the exception of interferon-gamma secretion, which was greater on d 5 and 14 in cows milked 1x. In conclusion, limiting milk production in early lactation had positive effects on metabolite concentration, but larger studies are necessary to establish if this could reduce disease incidence.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".