PSVIII-17 A comparison of a monoculture barley crop to a barley-based complex mixture on forage yield, quality, dry matter intake, enteric methane emissions and growth performance of pregnant yearling heifers
Notice bibliographique
Résumé
Abstract The objective of the study was to compare forage yield and composition, dry matter intake (DMI), growth, and enteric methane emissions for heifers grazing a barley monoculture (MON) or a barley-based complex forage blend (COM). The 2-year study was conducted near Saint Brieux (SK, Canada) and evaluated 2 treatments with 4 paddocksּ treatment-1ּ yr-1. Treatments included MON (CDC Rosser) seeded at 123 kg/ha or a COM which contained barley seeded at 61.5 kg/ha and a mixture of species seeded at 12.3 kg/ha. The COM mixture included 54% millet (Proso and Japanese), 14% Italian ryegrass, 13.5% clover (Berseem, Persian, Crimson), 4.5% hairy vetch, 4.5% black oil sunflower, 3% forage collards, 3% turnips, 2% phacelia, and 1% chicory. Forages were seeded in alternating strips (0.4 ha) to create individual paddocks. Pregnant yearling heifers (n = 80/yr) were weighed on 2 consecutive days at the start and end of the study, randomly allocated based on BW to each treatment, and assigned to a paddock (10 heifers/paddock). Heifers were provided fresh forage daily. Grazing was initiated at the late milk stage for MON and continued until the hard dough stage of maturity. Paddocks were then swathed, and grazing continued resulting in 84 and 77 d in yr 1 and 2, respectively. Forage samples and residual forage were collected weekly to estimate forage yield, composition, and intake. Rib and rump fat measurements were taken at the start and end of the study. Methane emissions were measured using the sulfur hexafluoride (SF6) tracer gas technique over a 4-d period while grazing both standing and swathed crops in each year. Forage yield [dry matter (DM) basis] did not differ among treatments (P = 0.59) during the growing season averaging 5.6 t/ha and did not differ (P = 0.57) once swathed averaging 5.7 t/ha. Treatment and date of sampling affected (P < 0.01) the proportion of barley, with barley representing 95% of the DM for MON and 81% for COM. Chemical composition did not differ among treatments for OM, CP, NDF, lignin, and starch; however, DM tended (P = 0.08) to be less for COM, and ADF and WSC were greater (P = 0.01 and P = 0.02) for COM than MON. Dry matter intake (DMI) was not affected while grazing standing (P = 0.98) or swathed (P = 0.50) forages with mean values of 8.8 and 10.2 kg/d, respectively. Rib and rump fat did not differ, but average daily gain was 0.1 kg/d greater (P < 0.01) for COM than MON. As a result, gain:feed was 0.08 kg/kg greater for heifers grazing COM (P < 0.01) than MON. Enteric methane emissions did not differ for treatment when heifers were grazing standing (P = 0.77) or swathed (P ≥ 0.99) forages. Growing an annual complex forage mixture rather than a monoculture crop may improve growth of yearling heifers, but does not affect forage yield, DMI, or enteric methane production.
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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 | 0,000 | 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) | 0,001 | 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 ».