Kuhlers D L, Jungst S B
Animal and Dairy Science Department, Auburn University, AL 36849-5415.
J Anim Sci. 1993 Mar;71(3):595-601. doi: 10.2527/1993.713595x.
Correlated responses in reproductive and carcass traits from a line of Landrace pigs selected for increased 200-d weight along with a randomly selected control line were studied in 195 litters (109 select, 86 control) and 285 pigs (132 select, 153 control). Reproductive and maternal traits studied included litter sizes born, born alive, and alive at 21 d and litter weights at birth and at 21 d. Carcass traits studied were carcass length, longissimus area, average backfat thickness, 10th-rib backfat thickness, specific gravity, weights of closely trimmed ham, loin, and shoulder, belly weight, subjective scoring of the longissimus muscle for color and marbling, estimated percentage of muscle, and lean growth. Total weighted cumulative selection differential for 200-d weight over six generations was 88.7 kg. The realized heritability for 200-d weight was .26 +/- .08, and the change in 200-d weight was 4.2 +/- 1.3 kg per generation. None of the regression coefficients for reproductive traits differed significantly from zero. Ham weight, belly weight, marbling score, and lean growth increased by .069 +/- .027 kg, .051 +/- .020 kg, .045 +/- .012 points, and .0042 +/- .0007 kg/d, respectively, per generation. Specific gravity decreased by -.00063 +/- .00023 per generation in response to the selection for 200-d weight. The increase in lean growth in the select line was the result of an increased growth rate and not from an improvement in percentage of lean in carcasses from pigs from the select line.
对一组为提高200日龄体重而选择的长白猪品系以及一个随机选择的对照品系的繁殖性状和胴体性状的相关反应进行了研究，共涉及195窝仔猪（109窝选择品系，86窝对照品系）和285头猪（132头选择品系，153头对照品系）。所研究的繁殖和母体性状包括产仔数、出生时存活仔猪数、21日龄存活仔猪数以及出生时和21日龄时的窝重。所研究的胴体性状包括胴体长度、背最长肌面积、平均背膘厚度、第10肋处背膘厚度、比重、去骨火腿重量、里脊肉重量、肩部重量、腹部重量、背最长肌颜色和大理石纹的主观评分、肌肉估计百分比以及瘦肉生长量。六代中200日龄体重的总加权累积选择差为88.7千克。200日龄体重的实现遗传力为0.26±0.08，每代200日龄体重的变化为4.2±1.3千克。繁殖性状的回归系数均无显著异于零。每代火腿重量、腹部重量、大理石纹评分和瘦肉生长量分别增加0.069±0.027千克、0.051±0.020千克、0.045±0.012分和0.0042±0.0007千克/天。响应于对200日龄体重的选择，比重每代下降-0.00063±0.00023。选择品系中瘦肉生长量的增加是生长速度提高的结果，而非来自选择品系猪胴体瘦肉百分比的改善。
