Berg E P, Neary M K, Forrest J C, Thomas D L, Kauffman R G
Purdue University, West Lafayette, IN 47907-1151, USA.
J Anim Sci. 1996 Nov;74(11):2672-8. doi: 10.2527/1996.74112672x.
Market weight lambs, average weight 52.5 kg (+/-6.1), were used to evaluate nontraditional live animal measurements as predictors of carcass composition. The sample population (n = 106) represented U.S. market lambs and transcended geographic location, breed, carcass weight, yield grade, and production system. Realtime ultrasonic (RU) measurements and bioelectrical impedance analysis (BIA) were used for development and evaluation of prediction equations for % boneless, closely trimmed primal cuts (BCTPC), weight or % of dissected lean tissue (TDL), and chemically derived weight or % fat-free lean (FFL). Longitudinal ultrasonic images were obtained parallel to the longissimus thoracis et lumborum (LTL), positioning the last costae in the center of the transducer head. Images were saved and fat and LTL depths were derived from printed images of the ultrasonic scans. Bioelectrical impedance analysis was administered via a four-terminal impedance plethysmograph operating at 800 microA at 50 kHz. Impedance measurements of whole-body resistance and reactance were recorded. Prediction equations including common linear measurements of live weight, heart girth, hindsaddle length, and shoulder height were also evaluated. All measurements were taken just before slaughter. Bioelectrical impedance measurements (as compared to RU and linear measurements) provided equations for %BCTPC, TDL, %TDL, FFL and %FFL with the highest R2 and lowest root mean square error. Even though BIA provided the best equations of the three methodologies tested, prediction of proportional yield (%BCTPC, %TDL, and %FFL) was marginal (R2 = .296, .551, and .551, respectively). Equations combining BIA, RU, and linear measurements greatly improved equations for prediction of proportional lean yield.
体重为市场平均水平的羔羊，平均体重52.5千克（±6.1千克），用于评估非传统活体动物测量指标作为胴体组成预测指标的效果。样本群体（n = 106）代表美国市场的羔羊，涵盖了不同地理位置、品种、胴体重、产量等级和生产系统。实时超声（RU）测量和生物电阻抗分析（BIA）用于开发和评估预测方程，以预测去骨、精修主要切块（BCTPC）的百分比、解剖瘦肉组织（TDL）的重量或百分比，以及化学衍生的无脂瘦肉（FFL）的重量或百分比。纵向超声图像平行于胸腰最长肌（LTL）获取，将最后一根肋骨置于换能器头部中心。图像被保存，脂肪和LTL深度从超声扫描的打印图像中得出。生物电阻抗分析通过一个四端阻抗体积描记器进行，该描记器在50 kHz频率下以800微安运行。记录全身电阻和电抗的阻抗测量值。还评估了包括活重、胸围、后臀长和肩高的常规线性测量值的预测方程。所有测量均在屠宰前进行。生物电阻抗测量（与RU和线性测量相比）为%BCTPC、TDL、%TDL、FFL和%FFL提供了R2最高且均方根误差最低的方程。尽管BIA在所测试的三种方法中提供了最佳方程，但比例产量（%BCTPC、%TDL和%FFL）的预测效果一般（R2分别为0.296、0.551和0.551）。结合BIA、RU和线性测量值的方程极大地改进了比例瘦肉产量预测方程。
