Fitting extended lactation curves of Holsteins
Bibliographic record
Abstract
The circadian timing system (CTS) synchronizes internal physiology with regularly occurring cues such as light-dark cycle.To understand the role of circadian rhythms in regulation of lactogenesis we exposed cows to chronic phase shifts in light-dark cycle (PS) to disrupt the CTS during the dry period.Milk production efficiency increased in PS exposed cattle with no detrimental effects on blood NEFA or BHB levels.Our objective was to measure effect of PS exposure on melatonin (MEL) and serotonin (5HT) levels and circadian rhythms in cows to determine if alterations were associated with changes in production efficiency.Briefly, 5 wks before expected calving (BEC) multiparous cows were moved to tie-stalls and divided into 2 treatments: control (C, n = 16; 16 h light: 8 h dark) or phase-shifted (PS, n = 16; exposed 6 h light-dark phase shifts every 3 d).All cows were exposed to control lighting after calving.Blood samples were taken at 0600 on d 35 BEC, 21 BEC, 2 before calving (BC), and d 0, 2, 9, 15 and 22 postpartum (PP).A subset of cows (n = 6/group) were sampled every 4 h over 48 h at 3 time points: d 23 BEC, 9 BEC, and 5 PP.LC-MS/MS was used to measure MEL and 5HT.Body temperature was recorded every 30 min vaginally using calibrated iButton data loggers at d 23 BEC and d 9 BEC.PS (P < 0.05) shifted phase and attenuated circadian rhythms of core body temperature.The overall effect of PS was to increase MEL and decrease 5HT (P < 0.05) at 0600 sampling.MEL was > 1.5-fold higher on d 15 PP and 22 PP in PS than C; whereas 5HT was 1.3-fold lower (P < 0.05).Cosine fit analysis found MEL circadian rhythms were significantly affected by treatment with C cows exhibiting strong rhythms across 3 time points (r 2 ≥ 0.72; P < 0.01) and PS cows only fitting 24 h rhythm at d 23 BEC (r 2 ≥ 0.72; P < 0.01).Circadian rhythms of blood 5HT was only evident at d 9 BEC in C cows (r 2 = 0.68; P < 0.01), area under the curve of 5HT (170 ± 29 and 235 ± 29 mg/ml; P = 0.13) and MEL (1.62 ± 0.15 and 1.94 ± 0.14 ng/mL; P = 0.14) was increased from d 9 BEC to 5 PP, respectively across the treatments.These data led to hypothesis that the attenuation of circadian rhythms facilitates lactogenesis to increase milk production efficiency.
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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 | 0.006 | 0.028 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.009 | 0.003 |
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".