Kaplon M J, Rothschild M F, Berger P J, Healey M
Dept. of Anim. Sci., Iowa State University, Ames 50011.
J Anim Sci. 1991 Feb;69(2):551-8. doi: 10.2527/1991.692551x.
Performance test records collected from 1978 to 1987 from on-farm tests of young Polish Large White boars from 94 herds and reproductive records of Polish Large White sows from 81 nucleus farms were used to estimate the phenotypic, environmental, and genetic trends. There were, after editing, 114,347 boar performance records and 41,080 litter records on sows. Both data sets were analyzed by use of an animal model. Estimated annual phenotypic and environmental trends were relatively large and desirable and were, respectively, .17 +/- .05, .11 +/- .05 (number born alive); .16 +/- .04, .10 +/- .04 (21-d litter size); 1.86 +/- .63, 1.43 +/- .62 (21-d litter weight, kg); 6.80 +/- .60, 6.76 +/- .72 (average daily gain, g/d); -.065 +/- .007, -.058 +/- .023 (backfat thickness, mm); -2.76 +/- .28, -2.75 +/- .29 (days to 110 kg). In contrast, all estimated genetic trends were relatively small and not always favorable. The genetic trends estimated from animal, sire and dam genetic values were, respectively, .01 +/- .01, .02 +/- .01, .01 +/- .01 (number born alive and 21-d litter size); .04 +/- .06, .10 +/- .05, .05 +/- .04 (21-d litter weight, kg); .04 +/- .04, .50 +/- .10, -.43 +/- .05 (average daily gain, g/d), -.009 +/- .001, -.015 +/- .002, -.004 +/- .0004 (backfat thickness, mm); and -.01 +/- .01, -.17 +/- .04, .19 +/- .02 (days to 110 kg). Neither examination of selection practices nor boar utilization provided an explanation for the lack of genetic progress.
1978年至1987年期间从94个猪群的波兰大白幼龄公猪农场测试中收集的性能测试记录，以及来自81个核心猪场的波兰大白母猪繁殖记录，用于估计表型、环境和遗传趋势。编辑后，有114,347条公猪性能记录和41,080条母猪窝产记录。两个数据集均使用动物模型进行分析。估计的年度表型和环境趋势相对较大且令人满意，分别为：每窝活产仔数为0.17±0.05、0.11±0.05；21日龄窝仔数为0.16±0.04、0.10±0.04；21日龄窝重（千克）为1.86±0.63、1.43±0.62；平均日增重（克/天）为6.80±0.60、6.76±0.72；背膘厚（毫米）为-0.065±0.007、-0.058±0.023；达110千克体重日龄为-2.76±0.28、-2.75±0.29。相比之下，所有估计的遗传趋势相对较小，且并非总是有利。从动物、父系和母系遗传值估计的遗传趋势分别为：每窝活产仔数和21日龄窝仔数为0.01±0.01、0.02±0.01、0.01±0.01；21日龄窝重（千克）为0.04±0.06、0.10±0.05、0.05±0.04；平均日增重（克/天）为0.04±0.04、0.50±0.10、-0.43±0.05；背膘厚（毫米）为-0.009±0.001、-0.015±0.002、-0.004±0.0004；达110千克体重日龄为-0.01±0.01、-0.17±0.04、0.19±0.02。对选择方法的检查和公猪的利用情况均无法解释遗传进展的缺乏。
