Nitrogen efficiency in cows fed red clover- or alfalfa-silage-based diets differing in rumen-degradable protein supply
Notice bibliographique
Résumé
Nitrogen pollution is an important issue in modern agriculture. For the dairy industry, increasing the efficiency of milk protein production may reduce the environmental impact of commercial farms. Optimal N utilization can be achieved by combining forage and concentrate varying in their degradability in the rumen. The aim of this study was to gain insight into the fate of dietary N as affected by forage type and rumen-degradable protein supply in lactating dairy cows, with an emphasis on milk N efficiency. Four rumen-fistulated Holstein cows were used in a 4 × 4 Latin square design balanced for residual effects. Four treatments consisting of a 2-by-2 factorial arrangement of alfalfa silage (AL) or red clover (RC)-based diets designed to satisfy 100 (rumen-degradable protein (RDP)-100) or 85% (RDP-85) of rumen degradable protein demand, by varying the amounts of ground and steam-flaked corn grain, as well as non-treated and heat-treated soybean meals. Dietary CP concentrations were greater in diets based on AL as compared with RC (P < 0.01). Kinetics of in sacco N disappearance revealed that the rapidly disappearing fraction was lower with RC than with AL diets, and this difference tended to be more pronounced for RDP-85 than RDP-100 (interaction, P = 0.06). On the contrary, slowly disappearing N fraction and fractional rate of disappearance were greater for RC as compared with AL diets (P < 0.01). Reducing RDP from 100 to 85% of requirements increased the slowly disappearing N fraction, but decreased the rapidly disappearing fraction and the fractional rate of disappearance of N (P < 0.01). Intakes of DM and N were lesser with RC compared with AL, and these differences were more pronounced with RDP-85 than with RDP-100 (interaction, P ≤ 0.04). As a proportion of N intake, fecal excretion tended to be greater (P = 0.09), whereas urinary excretion was lower (P = 0.04) with RC than with AL diets. Milk yield (tendency; P = 0.07) and total N secreted in milk were reduced (P < 0.01) with RC compared with AL diets. Feeding RC increased milk N efficiency (g of milk N/ kg of N intake) as compared with AL, and this difference tended to be of greater magnitude for RDP-85 than RDP-100 (interaction, P = 0.06). In conclusion, combining forage and concentrate of different CP degradability can improve milk N efficiency in dairy cows.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 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 ».