Effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in gastrointestinal, adipose, and liver tissue of Holstein dairy calves
Bibliographic record
Abstract
The objective of this study was to evaluate the effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in Holstein dairy calves. Seventy-one day-old calves [38.8 ± 4.4 kg, body weight ( BW ) ± sd] blocked by gender and birth BW, were randomly assigned to a 2 × 2 factorial arrangement of treatments. The first factor was weaning age [6 weeks (early) vs . Eight weeks (late)], the second factor was weaning pace [abrupt (4 step-down over 3 d, the initial milk replacer was 7.6 L, which was reduced 1.9 L in each step-down) vs . gradual (7 step-down over 14 d, the initial milk replacer was 7.6 L, which was reduced 1.09 L in each step-down)], generating early-abrupt ( EA ), early-gradual ( EG ), late-abrupt ( LA ), and late-gradual ( LG ) treatments. All treatments had 10 female and 8 male calves, except EA that had 1 fewer male calf. Milk replacer ( MR ; 24% CP, 17% fat) was bottle-fed, up to 1,200 g/d, twice daily (0600h and 1800h). EA and EG calves received 46.2 kg MR while LA and LG calves received a total of 63 kg MR. The study had 2 cohorts (2020, n=40; 2021, n=31), and each cohort included all treatments. Blood was collected from the jugular vein at 0900h on d 3 and d 7 of age, a day before starting and a day after weaning completion; male calves were humanely killed a day post-weaning. Rumen, jejunum, large intestine, liver, omental adipose and perirenal adipose tissues were sampled to determine the mRNA abundance of inflammation-related genes. Weaning pace, age, and pace × age, birth BW, and sex were included as fixed and cohort was included as random effects in the model. Blood metabolites and cortisol were analyzed as repeated measure, and sampling day, pace × sampling day, and age × sampling day were also included as additional fixed effects. Significance were noted at P ≤ 0.05 and tendencies when 0.05 < P ≤ 0.10. EA calves showed a tendency to have the greatest nonesterified fatty acid ( NEFA ) concentration compared with all other treatments. There was a pace × day effect on serum NEFA and β-hydroxybutyrate ( BHBA ); calves weaned in abrupt pace had an increased NEFA post-weaning compared with that for gradual weaning. Calves weaned in the gradual pace showed the greatest serum BHBA post-weaning. Most mRNA abundance of inflammation-related genes affected by treatments showed a similar pattern; downregulated by the abrupt (liver IL-1β) and early weaning (jejunum TNF-α and ICAM), and in some cases the interaction intensified the effect, demonstrating a weakened immune response in calves experiencing more stressful conditions (EA: IL-6 in the liver and NF-κB in the perirenal adipose tissue). Overall, the downregulation of mRNA abundance of inflammation-related genes in EA calves may be attributed to the suppression of the immune system and an immature immune response. Furthermore, the greater NEFA in EA calves could be attributed to a reduced starter intake, less developed rumen, or shorter time during the weaning transition.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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 | 0.001 |
| 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".