Impacts of reducing the dry period to 40 days and eliminating the far-off diet on milk production, rumen and blood parameters, liver gene expression and rumen microbiome profile of holstein dairy cows
Notice bibliographique
Résumé
Effects of a short 40-d dry period with only a close-up diet (SHORT) and a conventional 60-d dry period with a 39-d far-off and a 21-d close-up diet (CONV) on milk production, feed intake, blood and rumen parameters, liver gene expression and rumen microbiota profile were compared in 11 second-parity and 15 third and later parity cows. Milk production was recorded daily during the first 16 wks of lactation. Differential liver gene expression was assessed by affymetrix microarray analysis and DNA extracted from rumen samples was subjected to Illumina sequencing for exploring the microbiome profile. The SHORT treatment reduced milk yield and DMI after calving in third and later parity cows, but not in second-parity cows when compared to the CONV treatment. Cows on the SHORT treatment had higher concentrations of NEFA in blood plasma and tended to have higher liver TAG immediately after calving. These effects tended to be greater in third- and later parity cows compared to second-parity cows. Expression patterns of genes involved in β-oxidation at the first week of lactation compared to those at three weeks before calving showed lower hepatic β-oxidation capacity in cows on the SHORT treatment compared to those on the CONV treatment. During this period, the expression of DGAT, a key gene in the triglyceride synthesis, increased in SHORT-treatment cows while it remained unchanged in CONV-treatment cows. The expression patterns of genes involved in gluconeogenesis showed a higher capacity at first week after calving in cows on the SHORT compared to those on the CONV treatment. Our study also showed that the SHORT treatment increased the relative abundance of Firmicutes and reduced the relative abundance of Bacteroidetes compared to the CONV treatment and reduced the shifting of rumen microbiota from before to after calving. Results also demonstrated that the rumen microbiota was more stable in the SHORT treatment during the transition period. Based on these results, a 40-d dry period management with only a close-up diet might be beneficial for second parity cows. However, this treatment may be detrimental for older cows as excessive energy intake and fat deposition during the dry period in these animals result in lower milk production and higher mobilization of NEFA and accumulation of fat in the liver.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 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 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 tête enseignante, 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 ».