The Effects of Ractopamine and Hormonal Growth Promotants on Growth and Meat Quality of Crossbred Angus Steers
Notice bibliographique
Résumé
ObjectivesMeat tenderness is an important quality parameter that influences consumer preference. The cattle industry has over the years seen the emergence of feed additives and hormonal growth promotants in the form of β-adrenergic agonists (β-AA) and steroids, respectively. The objective of this study was to analyze the effect of hormonal growth implants and ractopamine on slaughter weight and meat quality parameters of steers selected for high (inefficient) and low (efficient) residual feed intake (RFI) performance.Materials and MethodsForty-eight crossbred Angus steers identified from individual GrowSafe data as high (n = 21) or low (n = 27) RFI cattle were randomly assigned to pens according to treatment (n = 12). Treatments included control (no ractopamine hydrochloride (RAC)/no steroids), RAC and steroids, steroids only, and RAC only in a 2x2x2 factorial design. Steers on steroid treatment received a first implant (200mg progesterone, 20mg estradiol benzoate and 29mg tylosin tartrate) at about 350 d of age and 450kg live weight and a terminal implant (120 mg trenbolone acetate and 24mg estradiol) at about 100 d before slaughter. RAC was fed to the appropriate group 28 d before slaughter at a rate of 200mg head–1d–1. Cattle were slaughtered at about 16 mo of age over 6 consecutive weeks by weight and back fat, with 1 animal per treatment represented in each kill for a total of 8 animals slaughtered per week. Hot carcass weights (HCW) were recorded. Gluteus medius (GM) muscles were obtained from the carcasses 3 d post mortem and halved for ageing, with one half aged a further 12 d under vacuum. After ageing at 4°C, muscle halves were assessed for pH, color, drip loss and Warner-Bratzler shear force (WBSF). For all data the experimental unit was the steer as the effect of ageing was not considered. Data was analyzed using the General Linear Model procedure in SAS (SAS Inst. Inc., Cary, NC) with RFI, steroids, RAC and their interactions as fixed factors with slaughter day used as a covariate. Mean differences were determined using Least Square Means and Tukey’s multiple comparisons.ResultsResults revealed no effect (P > 0.05) of RFI and RAC on slaughter weight (SW) but steroids increased (P < 0.0001) SW of steers. An interaction effect (P = 0.0381) was seen between RFI, steroids and RAC on HCW, where high RFI steers that were implanted with steroids and fed RAC had a higher HCW at 389.64 ± 8.70 kg than low RFI steers that were neither implanted nor fed RAC (325.68 ± 7.05kg). An interaction between RFI, steroids and RAC (P = 0.045) for drip loss was observed on muscles aged for 12 d, where high RFI steers that were implanted but not fed RAC had a higher drip loss (1.93 ± 0.23 g) than low RFI steers that were not implanted but feed RAC (0.63 ± 0.19g). Muscles from implanted steers had a higher mean WBSF value than muscles from non-implanted steers on d 12 post-mortem (P = 0.039), while high RFI steers that received RAC had the lowest mean WBSF (P = 0.015).ConclusionResults indicated that steroids compromised the development of tenderness during post mortem ageing in the GM. This suggests that the benefit of steroid use on slaughter and hot carcass weights will compromise tenderness of this muscle. Additional post mortem ageing beyond 12 d may be required. Conversely, the use of the β-AA RAC showed potential for decreasing cooked GM toughness in high RFI steers regardless of the ageing period.
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 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 | 0,001 |
| 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 | 0,001 |
| 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 ».