Lactational performance effects of supplemental histidine in dairy cows: A meta-analysis
Notice bibliographique
Résumé
The objective of this meta-analysis was to examine the effects of supplemental His on lactational performance, plasma His concentration and efficiency of utilization of digestible His (Eff His ) in dairy cows. The meta-analysis was performed on data from 17 studies published in peer-reviewed journals between 1999 and 2022. Five publications reported data from 2 separate experiments, which were included in the analyses as separate studies, therefore resulting in a total of 22 studies. In 10 studies, His was supplemented as rumen-protected (RP) His; in 1 study, 2 basal diets with different dHis levels were fed; and in the remaining experiments, free His was infused into the abomasum (4 studies), the jugular vein (3 studies) or deleted from a mixture of postruminally infused AA (4 studies). The main forages in the diets were corn silage in 14 and grass silage in 8 studies. If not reported in the publications, the supplies of dietary CP, metabolizable protein (MP), net energy of lactation, and digestible His (dHis) were estimated using NRC (2001). An initial meta-analysis was performed to test the standard mean difference (SMD; raw mean difference of treatment and control means divided by the pooled standard deviation of the means), that is, effect size, and the corresponding 95% confidence interval (CI) in production parameters between His-supplemented groups versus control. Further, regression analyses were also conducted to examine and compare the relationships between several response variables and dHis supply. Across studies, His supplementation increased plasma His concentration (SMD = 1.39; 95% CI: 1.17–1.61), as well as DMI (SMD = 0.240; 95% CI: 0.051–0.429) and milk yield (MY; SMD=0.667; 95% CI: 0.468–0.866), respectively. Further, milk true protein concentration (MTP; SMD=0.236; 95% CI: 0.046–0.425) and milk true protein yield (MTPY; SMD=0.581; 95% CI: 0.387–0.776) were increased by His supplementation. Notably, the increase in MTP concentration and MTPY were 3.9 and 1.3 times greater for studies with MP-deficient (according to NRC 2001) diets compared with studies with MP-adequate diets. The regression analyses revealed that production parameters (DMI, MY, and MTPY) responded in a nonlinear manner to increasing His supply. Further, we detected a difference in the magnitude of change in MTPY and plasma His concentration with the level of His supply and between His supplementation methods, being greater for infused His compared with RPHis. Lastly, a linear and negative relationship between Eff His and the ratio of total digestible His to net energy for lactation supply was observed, indicating an important interaction between dHis and energy supply and Eff His (i.e., utilization of dHis to support protein export). Overall, these analyses confirm His as an important AA in dairy cattle nutrition.
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 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 | 0,013 | 0,016 |
| Méta-épidémiologie (sens strict) | 0,003 | 0,002 |
| Méta-épidémiologie (sens large) | 0,013 | 0,044 |
| Bibliométrie | 0,003 | 0,004 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,003 | 0,001 |
| Science ouverte | 0,002 | 0,001 |
| Intégrité de la recherche | 0,002 | 0,002 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 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 ».