Level and source of fat in the diet of gestating beef cows. II. Effects on the postpartum performance of the dam and the progeny1
Notice bibliographique
Résumé
A study was conducted to evaluate the effects of level and source of fat in the diet of gestating beef cows on the postpartum performance of the dam and the progeny. Each year, 75 mature pregnant (183±4.8 d until calving) Angus cows with similar BW (663±21.5 kg) and BCS (2.6±0.12; 1 to 5 scale) were randomly assigned to one of 15 outdoor pens. Each pen was assigned to one of three iso-caloric and iso-nitrogenous treatments: a low-fat diet (LF; 1.4±0.12% EE), and two high-fat diets (HF; 3.3±0.20% EE) including a canola seed (CAN) or a flaxseed (FLX) based pelleted feed. Diets were formulated to meet the requirements of pregnant beef cows and fed until calving. Data were analyzed as a randomized complete block design with contrasts for the effects of level (LF vs. HF) and source (CAN vs. FLX) of fat. No differences (P≥0.21) were found for BW or calving to weaning ADG of cows. The average BCS during the first 42 d of lactation was greater (P<0.01) for LF compared to HF (2.63 vs. 2.51) with no difference (P=0.35) for CAN vs. FLX cows. Subcutaneous fat thickness over the ribs was greater (P≤0.01) for LF compared to that of HF cows at calving (5.7 vs. 4.3 mm) and at weaning (4.3 vs. 3.7 mm) with no difference (P≥0.11) for CAN vs. FLX cows. Over the first 42 d of lactation, no difference (P≥0.23) was observed for 12-h milk yield. Milk protein concentration was greater (P=0.03) for CAN compared to FLX (3.11 vs. 3.01%) cows while no difference (P≥0.28) was observed for any other milk component. Milk fat from FLX cows had greater (P < 0.01) CLA and CLnA concentrations than that of CAN cows during the first 42 d of lactation. Pregnancy rate of HF cows tended (P=0.07) to be greater than that of LF cows with no difference (P=0.77) for CAN vs. FLX cows. Calves from HF cows were heavier (P≤0.01) at birth (42.9 vs. 40.2 kg) than those from LF cows. From calving to weaning, ADG of calves born to CAN cows was greater (P=0.03) that that of calves born to FLX cows (1.19 vs. 1.13 kg/d) with no difference (P=0.18) for calves born to LF vs. HF cows. At slaughter, progeny of HF cows had greater (P≤0.03) shrunk BW (605 vs. 579 kg) and HCW (355 vs. 339 kg) compared to those from LF cows with no difference (P≥0.16) for progeny of CAN vs. FLX cows. These results show that feeding a HF diet over gestation results in heavier calves at birth and at slaughter, and superior calf gains from birth to slaughter as well as heavier carcasses, possibly due to a developmental programming effect.
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 | 0,001 | 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 | 0,000 |
| 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 ».