Cisneros F, Ellis M, Miller K D, Novakofski J, Wilson E R, McKeith F K
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
J Anim Sci. 1996 Nov;74(11):2566-76. doi: 10.2527/1996.74112566x.
Live animal real-time ultrasound scans and carcass measures were taken on 80 pigs comprising two sexes (42 barrows; 38 gilts) and two halothane genotypes (40 carriers and 40 negatives) that were slaughtered between 108 and 148 kg live weight. Transverse scans (TRUS), at right angles to the midline, were taken on right (RS) and left (LS) sides at the last rib. Longitudinal scans (LON) were taken 6.5 cm off the midline immediately anterior (ANT) and posterior (PST) to the last rib on both the RS and LS. Longissimus muscle depth and area and backfat thickness over the longissimus muscle were measured on TRUS. Backfat thickness and longissimus muscle depth were measured at each end of the LON. Backfat thickness and longissimus muscle measurements were taken at the 10th and last rib on the RS of the carcass. Carcasses were fabricated using standard techniques to establish lean cut yields and carcass soft tissue was chemically analyzed to determine fat-free lean contents. Stepwise regression analysis was performed to develop equations to predict the weights and percentages of lean cuts and fat-free lean. Fat and muscle measures taken from ultrasound scans were generally less accurate than last rib carcass measures at predicting composition. There was little difference in R2 for equations based on either TRUS or ANT/LON; however, PST/LON, generally, were less accurate than ANT/LON. Combining measurements from more than one scan gave little improvement in R2 compared with the best single scan. Estimates of sex bias for carcass composition prediction were small. Halothane genotype and carcass lean content biases were detected; equations derived from the pooled data tended to overestimate the lean content of negative pigs and fatter carcasses and underestimate the lean content of carrier animals and leaner carcasses.
对80头猪进行了活体动物实时超声扫描和胴体测量，这些猪包括两种性别（42头阉公猪；38头小母猪）和两种氟烷基因型（40头携带者和40头阴性猪），它们在108至148千克活体体重时被屠宰。在最后一根肋骨处，与中线成直角进行横向扫描（TRUS），分别在右侧（RS）和左侧（LS）进行。纵向扫描（LON）在RS和LS上，在最后一根肋骨前方（ANT）和后方（PST）距中线6.5厘米处进行。在TRUS上测量背最长肌深度、面积以及背最长肌上方的背膘厚度。在LON的两端测量背膘厚度和背最长肌深度。在胴体右侧的第10根和最后一根肋骨处测量背膘厚度和背最长肌。使用标准技术分割胴体以确定瘦肉切块产量，并对胴体软组织进行化学分析以确定无脂瘦肉含量。进行逐步回归分析以建立预测瘦肉切块重量和百分比以及无脂瘦肉的方程。从超声扫描获得的脂肪和肌肉测量值在预测组成方面通常不如最后一根肋骨处的胴体测量值准确。基于TRUS或ANT/LON的方程在R2上差异不大；然而，一般来说，PST/LON不如ANT/LON准确。与最佳单次扫描相比，组合来自多个扫描的测量值在R2上几乎没有改善。胴体组成预测的性别偏差估计值较小。检测到氟烷基因型和胴体瘦肉含量偏差；从合并数据得出的方程往往高估阴性猪和较肥胴体的瘦肉含量，而低估携带者动物和较瘦胴体的瘦肉含量。
