Effects of canola meal inclusion rate in starter mixtures for Holstein heifer calves on dry matter intake, average daily gain, ruminal fermentation, plasma metabolites, and total-tract digestibility
Notice bibliographique
Résumé
The objective of this study was to determine the effects of the canola meal (CM) inclusion rate in pelleted starter mixtures for Holstein heifer calves on dry matter intake, average daily gain, ruminal fermentation, plasma metabolites, and total-tract digestibility. Fifty Holstein heifer calves were blocked by birth date and body weight and, within block, randomly assigned to 1 of 5 pelleted starter treatments with 0, 15, 30, 45, or 60% of the crude protein supplied by CM instead of soybean meal (SBM). Pellets were formulated to be similar in crude protein (24.3%), starch (26.6%), and neutral detergent fiber (17.8%) and were provided to calves starting on d 8 of age, with starter intake measured daily. From 8.0 ± 0.0 (mean ± standard deviation) d of age through d 35.3 ± 2.4, calves were fed milk replacer at 15% of body weight, offered in 3 equal feedings at 0600, 1500, and 2100 h. After that, a gradual 21-d step-down weaning process was imposed, where no further milk replacer was provided starting on d 57.0 ± 0.0. Data for milk replacer and starter intake were calculated to determine weekly averages. On d 62.2 ± 0.8 of age, blood was collected every 4 h and analyzed for glucose, β-hydroxybutyrate, insulin, and urea concentrations. From d 66.2 ± 0.8 of age and extending for 3 d, fecal samples were collected every 12 h with a 3-h daily offset, to estimate fecal nutrient output and to determine apparent total-tract digestibility. Additionally, ruminal fluid (d 70.2 ± 0.8 of age) was sampled at 1300 h through an esophageal tube connected to a vacuum pump. The pH of ruminal fluid was measured, and ruminal fluid was analyzed to determine short-chain fatty acid and ammonia concentrations. Data were analyzed with fixed effect of treatment and random effect of block. Polynomial contrasts were calculated to assess linear, quadratic, and cubic effects with repeated measures statement for variables analyzed over time. Starter intake, average daily gain, body weight, and feed efficiency did not differ among treatments. Crude protein and ether extract digestibility were affected in a cubic manner, where CP was greatest for CM0, CM30, and CM45, and ether extract digestibility was least for CM15 and CM60. The molar proportion of acetate responded cubically, but the proportions of propionate and butyrate did not differ among treatments. Ruminal ammonia and plasma urea concentrations were not affected by CM inclusion rate. In conclusion, CM can replace up to 60% of the CP provided from SBM without affecting starter intake and growth of calves.
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 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 | 0,001 | 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 ».