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
Notice bibliographique
Résumé
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.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».