1Department of Animal Science,Universidade Federal de Santa Maria,Avenida Roraima, 1000, Cidade Universitária, Bairro Camobi, Santa Maria, RS 97105-900,Brazil.
2Instituto Federal de Educação, Ciência e Tecnologia Farroupilha,Campus of Santo Augusto, Rua Fábio João Andolhe, 1100, Bairro Floresta, Santo Augusto, RS 98590-000,Brazil.
Animal. 2019 Aug;13(8):1744-1749. doi: 10.1017/S1751731118003178. Epub 2018 Nov 27.
The increase of sheep meat competitiveness in international markets can be attributed to the rise of the quantity and the improvement of the quality of the edible portion of sheep carcasses. Usually, carcass yield is established after the slaughter of the animals. Yet, when carcass yield is determined in vivo, it can be both a costly and subjective method. This study proposes models for predicting the physical characteristics of lamb carcass using bioimpedance analysis (BIA) in live animals. Thirty-one Texel × Ile de France crossbreed ram lambs were slaughtered at 20, 26, 32 or 38 kg of BW. Before the slaughter, values of resistance (Rs) and reactance (Xc) were collected using a single-frequency BIA equipment (Model RJL Quantum II Bioelectrical Body Composition Analyzer). Then, BIA main variables such as body bioelectrical volume (V), phase angle (PA), resistive density (RsD) and reactive density (XcD) were calculated. After slaughter, cold carcass weight (CCW), cold carcass yield (CCY), subcutaneous fat thickness (SFT), soft tissue weight (STW) and soft tissue yield (STY) were also measured. Multiple regression analyses were carried out using the physical characteristics as dependent variables and the bioimpedance values as independent variables. Predictive performance of the models was assessed using leave-one-out cross-validation. The prediction model of CCW was obtained using the V, PA and RsD (R2 = 0.97), STW through the V, RsD and XcD (R2 = 0.97), CCY by Rs, Z and XcD (R2 = 0.69), STY by V and XcD (R2 = 0.67), and SFT only for XcD (R2 = 0.84). The results indicated that BIA has the potential to predict carcass characteristics of lambs at different body masses.
羊肉在国际市场上竞争力的提高可归因于胴体可食部分数量和质量的提高。通常，胴体产率是在动物屠宰后确定的。然而，当在活体中确定胴体产率时，它既昂贵又主观。本研究提出了使用活体动物生物阻抗分析（BIA）预测羔羊胴体物理特性的模型。31 只特克赛尔× Ile de France 杂交公羊羔羊在 20、26、32 或 38 kg BW 时屠宰。屠宰前，使用单频 BIA 设备（Model RJL Quantum II 生物电阻抗身体成分分析仪）收集电阻（Rs）和电抗（Xc）值。然后，计算 BIA 主要变量，如身体生物电容积（V）、相位角（PA）、电阻密度（RsD）和电抗密度（XcD）。屠宰后，还测量冷胴体重（CCW）、冷胴体产率（CCY）、皮下脂肪厚度（SFT）、软组织重量（STW）和软组织产率（STY）。使用多元回归分析，将物理特性作为因变量，将生物阻抗值作为自变量。使用留一法交叉验证评估模型的预测性能。CCW 的预测模型通过 V、PA 和 RsD 获得（R2 = 0.97），STW 通过 V、RsD 和 XcD 获得（R2 = 0.97），CCY 通过 Rs、Z 和 XcD 获得（R2 = 0.69），STY 通过 V 和 XcD 获得（R2 = 0.67），SFT 仅通过 XcD 获得（R2 = 0.84）。结果表明，BIA 具有预测不同体重羔羊胴体特性的潜力。
