Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Area de Sistemas de Producción Animal, Consejería de Medio Ambiente y Desarrollo Rural, Principado de Asturias, 33300 Villaviciosa, Asturias, Spain.
J Anim Sci. 2010 Apr;88(4):1229-39. doi: 10.2527/jas.2009-2025. Epub 2009 Dec 4.
To examine the extent of the effect of muscular hypertrophy character in beef of northern-Spanish breeds, animal performance and carcass characteristics of 152 finishing steers from 5 genotypes were studied: 32 yearling bulls from a rustic Asturiana de la Montaña (AM) breed, 96 yearling bulls from Asturiana de los Valles (AV) breed, divided in 3 groups depending on the presence of the gene responsible for double-muscling (i.e., 32 AV mh/mh, 32 AV mh/+, 32 AV +/+), and 24 yearling bulls from AM x AV cross were used. Each genotype was composed of 8 animals per year (4 animals per pen) for 4 yr, except for the AM x AV genotype, which was only evaluated in the last 3 yr of the experiment. All animals were fed indoors with concentrate meal and barley straw ad libitum. Average daily gains in AV animals (1.41 kg/d) were greater (P < 0.01) than in AM (1.12 kg/d), whereas AM x AV were intermediate (1.29 kg/d) to these. No significant differences (P = 0.604) in ADG were found among the 3 AV genotypes. Longer fattening periods (P < 0.001) were taken for AM animals to reach acceptable BW at slaughter. Double-muscled animals (AV mh/mh) were found to have the best feed efficiencies when expressed as G:F (P < 0.001). However, residual feed intake calculated on a daily basis showed a greater efficiency in AV mh/mh and AM than in other genotypes. Carcasses from double-muscled animals had greater BW, yield, conformation and compactness index, and less fat cover than the other genotypes (P < 0.001). Carcasses from AM breed were the lightest and had the worst conformation, whereas those from AM x AV generally presented intermediate characteristics between AV and AM. Double-muscled animals had the greatest LM weight and area. The sixth-rib dissection revealed a greater percentage of muscle (84.6%) and decreased percentages of subcutaneous fat (1.1%), intermuscular fat (4.7%), bone (8.5%), and other tissues (1.2%) in AV mh/mh compared with other genotypes. Water-holding capacity was greatest in AM and least in AV mh/mh. In conclusion, double-muscled AV bulls would provide the greatest economic returns at intensive feeding systems because of their greater efficiency, reduced feeding costs, greater carcass weight and conformation, and greater lean yields, though some LM characteristics (reduced fat content and water-holding capacity) could negatively affect the sensory attributes of the meat compared with other genotypes with greater fatness.
为了研究北方西班牙品种牛肉肌肉肥大特征的影响程度，研究了 5 种基因型的 152 头育肥公牛的动物性能和胴体特征：32 头来自山区阿斯图里亚纳（AM）品种的小牛，96 头来自山谷阿斯图里亚纳（AV）品种的小牛，根据是否存在导致双肌的基因（即 32 头 AV mh/mh、32 头 AV mh/+、32 头 AV +/+)，分为 3 组，24 头来自 AM x AV 杂交的小牛。每个基因型由 8 头动物组成（每栏 4 头），饲养 4 年，除 AM x AV 基因型外，该基因型仅在实验的最后 3 年进行评估。所有动物均在室内自由采食浓缩饲料和大麦秸秆。AV 动物的平均日增重（1.41kg/d）大于 AM（1.12kg/d）（P<0.01），而 AM x AV 则介于两者之间。在 3 种 AV 基因型之间未发现 ADG 有显著差异（P=0.604）。AM 动物需要更长的育肥期（P<0.001）才能达到可接受的屠宰体重。双肌动物（AV mh/mh）的饲料效率最高，以 G:F 表示（P<0.001）。然而，根据每日计算的剩余采食量，AV mh/mh 和 AM 的效率高于其他基因型。双肌动物的胴体具有更大的体重、产肉率、一致性和紧凑度指数，脂肪覆盖率低于其他基因型（P<0.001）。AM 品种的胴体最轻，一致性最差，而 AM x AV 品种的胴体通常介于 AV 和 AM 之间。双肌动物的 LM 重量和面积最大。第六肋骨解剖显示，与其他基因型相比，AV mh/mh 中的肌肉（84.6%）百分比更大，皮下脂肪（1.1%）、肌间脂肪（4.7%）、骨骼（8.5%）和其他组织（1.2%）百分比更小。水分保持能力在 AM 中最大，在 AV mh/mh 中最小。总之，由于双肌 AV 公牛具有更高的效率、降低的饲料成本、更大的胴体重量和一致性以及更大的瘦肉产量，因此在密集饲养系统中会带来最大的经济效益，尽管一些 LM 特征（降低的脂肪含量和水分保持能力）可能会对与其他基因型相比，肉类的感官特性产生负面影响，因为其他基因型的脂肪含量更高。
