Mitigation of variability between competitively fed dairy cows through increased feed delivery frequency
Notice bibliographique
Résumé
The objective of this study was to determine whether increased frequency of total mixed ration (TMR) delivery could mitigate the effects of feed bunk competition on the behavior and productivity of individual lactating dairy cows within a group. We hypothesized that, for competitively fed cows, a greater frequency of TMR delivery would improve access to feed, and reduce individual variability in behavior, meal patterns, and production between cows. Sixteen lactating Holstein dairy cows (first lactation = 4, second lactation = 5, ≥ third lactation = 7) averaging 72 ± 35 d in milk and producing 42 ± 6 kg of milk/d at the start of the trial, were categorized as either young (≤ second lactation) or mature (≥ third lactation) and paired to maximize difference in parity. Pairs were housed 4 at a time and competitively fed a TMR at a ratio of 2 cows:1 feed bin. Cow pairs were exposed, in a crossover design, to each of 2 feed delivery frequency treatments: low (2×/d) and high (6×/d) frequency. Treatments were applied for 10 d, with dry matter intake (DMI), feeding behavior (feeding time, feeding rate, and meal patterns), and replacement frequency for each cow recorded using an automated feed intake system on d 6 to 10 of each period. Rumination time, feed sorting, lying behavior, and productivity were also measured for this period. Variability in behavior within pairs of cows was determined by averaging the absolute difference within each pair over the recording period to provide 1 value per pair. Frequency of TMR delivery did not affect feeding time, feeding rate, DMI, replacement frequency, feed sorting, or productivity. At the high delivery frequency, there was a tendency for rumination time to increase [low = 519.3; high = 544.3 min/d; standard error of the difference (SED) = 11.32], and to be more variable within pairs (low = 38.0, high = 50.0 min/d; SED = 5.57). Cows also had longer lying bouts at the high delivery frequency (low = 53.0; high = 55.5 min/bout; SED = 1.00). No differences in daily meal patterns were found between treatments; however, the average first meal following each feeding indicated that cows under the high delivery frequency spent less time, consuming smaller meals during peak feeding periods. Comparing the young and mature individuals within each treatment pair revealed that feeding rate (young = 0.16; mature = 0.19 kg/min; SED = 0.014) and DMI (young = 25.6; mature = 28.6 kg of DM/d; SED = 1.36) were lower for the young cows on both treatments. Meal frequency was greater in young cows (young = 9.0; mature = 7.5 meals/d; SED = 0.71) and meal size was greater in mature cows (young = 3.2; mature = 4.2 kg of DM/meal; SED = 0.32) across treatments. These results suggest that for cows fed at a high level of competition, increasing TMR delivery frequency from 2 to 6×/d led to consumption of shorter, smaller meals during peak periods of feed consumption. However, under these conditions, the relative parity of competitively fed cows had a greater effect on feeding behavior, meal patterns, and production than did the frequency of feed delivery.
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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) | 0,000 | 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 | 0,001 |
| 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 ».