Evaluation of lighting programs, diet density, and short term use of mash as compared to crumbled starter to reduce incidence of sudden death syndrome in broiler chicks to 35 d of age
Notice bibliographique
Résumé
Restricted lighting is used commercially to regulate early growth and limit losses associated with sudden death syndrome (SDS), ascites and leg problems. Standard lighting programs may not be suited for broilers marketed at 35 d of age, and promote injury (scratching, i.e., cellulitis) by creating peak feeding periods. This study evaluates four lighting programs, three phases of mash or crumble starter feeding and two diet densities on performance and mortality of broilers marketed at 35 d of age. Two trials each utilized 7200 male broiler (Cobb × Cobb) chicks randomly housed in six (2.75 × 4.90 m) floor pens in each of eight rearing rooms. Four lighting programs were replicated in each trial and consisted of: (a) 23C (23L:1D 0–35 d); (b) 16C (23L:1D 0–3 d, 16L:8D 4–35 d); (c) DDI (delayed decreasing increasing) (23L:1D 0–3 d; 20L:4D 4–6 d, 16L:8D 7–10 d; 8L:16D 11–15 d; 12L:12D 16–20 d; 16L:8 D 21–28 d; and 20L:4 D 29–35 d); and (d) IL (intermittent lighting, provided in four cycles of 6 h d -1 the same total daily hours of light as the DDI program). Two diet densities were applied for the starter and grower diets; high (ME 3170/3200 kcal; CP 251/210 g) or low (ME 3100/3060 kcal; CP 235/195 g kg -1 starter/grower diet, respectively). The two starter types were fed as combinations of mash (M) or crumble (C): (1) M 0–12 d followed by C 12–21 d; (2) C 0–12 d followed by M 12–21 d; and 3) C 0–21 d. The respective grower/finisher density diets were fed in a pelleted form. By 35 d of age the body weight (BW) of broilers maintained under the DDI lighting program was significantly lower than BW of broilers held under the other lighting programs (16C a > IL ab > 23C b ). Overall (0–35 d) feed conversion (corrected for mortality, but not market weight at 35 d) was highest for broilers reared under the 23C a > IL ab > DDI b > 16C c lighting programs, respectively. SDS (%) mortality was highest for IL (1.68 a ) = 23C (1.53 a ) ≥ 16C (1.02 ab ) ≥ DDI (0.80 b ) lighting programs. There were no significant differences in 35 d BW or feed conversion of broilers fed mash or crumble starter. Feeding mash diets did lower 21 d BW, but this decrease in early growth did not significantly reduce overall mortality. Broilers fed the low as compared to the high density diets weighed less at 21 d, but weighed significantly more at 35 d, and had a higher (P < 0.05) 0–35 d feed conversion. Low as compared to high density diets did reduce SDS mortality significantly (0.72 vs. 1.81%, respectively). Lighting programs that do provide variable extended dark periods will alleviate broiler mortality as compared to constant (23 or 16 h) or intermittent lighting programs. However, these broilers had a significantly lower body weight when marketed at 35 or less days of age. Key words: Lighting, broilers, mash, diet density, sudden death, ascites
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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 | 0,001 | 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 | 0,000 | 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) | 0,000 | 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 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 ».