Cattle performed as well as sheep when grazing a river saltbush (Atriplex amnicola)-based pasture
Notice bibliographique
Résumé
In Mediterranean-type climates, saltbush grown on saline land offers producers valuable feed during the autumn feed gap. Saltbush has high crude protein concentrations, moderate to low energy concentrations and accumulates very high concentrations of soluble salt. As ruminants cannot store quantities of salt, intake of saltbush is limited by the individuals’ ability to excrete salt. The aim of this 6-week study was to compare the relative performance, diet selection and urine concentrating ability of mature sheep and cattle grazing a young stand of river saltbush (Atriplex amnicola) with a volunteer annual understorey, consisting of senesced and germinating annual grasses. We measured liveweight and condition score of 30 mature Merino wethers and 15 mature Hereford-cross cows grazing the same saltbush stand, with a volunteer understorey of predominantly annual grasses, for 6 weeks during late autumn. Saltbush intake and diet selection were estimated at the same time using sodium (Na) : creatinine ratios in urine and carbon isotope ratios in faeces. During the first 3 weeks of grazing, the data indicated that cattle significantly outperformed sheep with a 15% increase in liveweight compared with sheep with an average increase of 4%. It is possible that some of this difference may be associated with different rates of loss of digesta associated with restricted access to food in the 2 h before weighing. No differences were found between the proportion of plants with a C4 photosynthetic pathway (saltbushes) in the diets selected by sheep and cattle for the majority of grazing. The specific gravity and Na concentration of urine was similar across livestock species. While this provided no indication of a difference in ability to concentrate or excrete Na, sheep did have a consistently higher Na : creatinine ratio in urine. The higher ratio is consistent with more efficient Na excretion and this may be significant when the species graze saltbush without low salt supplement or if water is restricted. Historically, it has been thought that cattle would not perform as well as sheep when grazing saltbush, but under the conditions of this study, when feed on offer is not limiting dry matter intake and fresh water is available, cattle are able to utilise this out of season feed source as well as, or possibly better than, sheep.
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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 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,000 | 0,001 |
| 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 | 0,001 |
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 ».