The effect of prepartum feeding and lying space on metabolic health and immune function
Notice bibliographique
Résumé
The determinants of metabolic and reproductive health disorders in the peripartum period and the degree to which feeding and lying space and management can influence health are only partially understood. The objective of this randomized controlled study was to determine whether providing noncompetitive feeding and lying access in the close-up dry period improves health and immune function. Forty-eight Holstein cows of all parities were randomly assigned to a treatment group of 6 to 10 cows in 1 pen with either 80% cows to stalls and 90 cm of feeding space per cow (understocked) or 120% stocking density and 45 cm of feeding space per cow (overstocked) for 3 wk before expected calving. All cows wore electronic data loggers to monitor daily standing and lying time. Video recordings representing d 7 to 9 after group formation were reviewed, and a competition index (C_Ind) was calculated for each cow by dividing the number of times a cow displaced another as an actor by its total number of actor and reactor displacements. Cows were categorized as high success (C_Ind ≥0.6), moderate success (0.4 ≤ C_Ind <0.6), or low success (C_Ind <0.4). Weekly blood samples measured nonesterified fatty acids, β-hydroxybutyrate, calcium, glucose, albumin, aspartate aminotransferase, bilirubin, haptoglobin, insulin, and insulin-like growth factor-1 from 3 wk before to 5 wk after calving. Measures of innate immune function (neutrophil phagocytosis and oxidative burst) were assessed at -2, -1, 1, 2, 3, and 5 wk relative to calving. Liver biopsies were collected at wk 1 and 3. Cows in the understocked group spent significantly more time per day lying; the back-transformed least squares means and 95% confidence interval were 14.8 h (13.9-15.6) versus 12.8 h (12.0-13.7). Controlling for parity, there was no difference between treatments in β-hydroxybutyrate, nonesterified fatty acids, glucose, insulin, insulin-like growth factor 1, aspartate aminotransferase, bilirubin, or haptoglobin concentrations. Throughout the study, cows in the understocked treatment had higher mean calcium and tended to have higher albumin and at 3 wk after calving tended to have lower mean liver triacylglycerol content. Overall, there was no treatment effect on phagocytosis, but cows with a higher C_Ind in the understocked treatment group had greater oxidative burst function. There was no effect of treatment on endometritis. Despite increased competition and lower lying time, the expected harmful effects of crowding and competition on metabolic indicators and innate immune function were mostly not observed. Although this does not refute the importance of access to feeding and lying space, these results indicate that metabolic and reproductive health is more complex than can be explained solely by exposure to what are understood to be best practices for space allowances.
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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 | 0,001 | 0,002 |
| 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 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».