Bullock K D, Kuhlers D L, Jungst S B
Dept. of Anim, and Dairy Sci., Auburn University, AL 36849-5415.
J Anim Sci. 1991 Apr;69(4):1409-19. doi: 10.2527/1991.6941409x.
Duroc boars from a line previously selected over five generations for 200-d weight and those from a randomly selected control line were mated to Landrace sows either from a line previously selected for increased 70-d weight or from a randomly selected pedigree control line. From these matings, 900 pigs were farrowed to examine the effects of crossing lines of pigs mass selected for weight at two ages on growth rate, survival, and carcass composition. A greater (P less than .01) percentage of pigs farrowed survived birth from control-line sows (.974) than from select-line sows (.914). Of those pigs born alive, a greater (P less than .05) percentage of pigs out of control-line sows survived to 21 d (.893) than out of select-line sows (.829). Pigs sired by select-line boars weighed 2.1 kg heavier (P less than .05) at 70 d than pigs sired by control-line boars. Pigs out of select-line sows weighed .11 kg less (P less than .10) at birth and .3 kg less (P less than .10) at 21 d of age but grew .026 kg/d faster (P less than .10) from 70 d to slaughter, weighed 3.9 kg more at 165 d of age (P less than .05), and reached 100 kg 7.0 d sooner (P less than .05) than pigs out of control-line sows. Carcasses from barrows sired by select-line boars had .29 cm more (P less than .10) fat at the 10th-rib than carcasses from barrows sired by control-line boars. Marbling scores were .31 unit greater (P less than .05) and muscle color scores were .25 unit greater (P less than .10) for carcasses from pigs out of select-line sows than for carcasses from pigs out of control-line sows. Selection for increased 70-d weight decreased age at 100 kg without increasing fat deposition. However, survival rates up to 100 kg were reduced. Mass selection for 200-d weight effectively increased 70-d weight, but fat thickness at 100 kg also increased.
来自一个经过五代选育、200日龄体重增加的杜洛克公猪品系，以及来自随机选择的对照品系的杜洛克公猪，与长白母猪交配。这些长白母猪要么来自一个经过选育、70日龄体重增加的品系，要么来自随机选择的系谱对照品系。通过这些交配，共分娩出900头仔猪，以研究两个年龄阶段体重选择的品系杂交对生长速度、存活率和胴体组成的影响。对照品系母猪所产仔猪的出生存活率（0.974）高于选择品系母猪所产仔猪（0.914），差异极显著（P<0.01）。在存活的仔猪中，对照品系母猪所产仔猪存活至21日龄的比例（0.893）高于选择品系母猪所产仔猪（0.829），差异显著（P<0.05）。选择品系公猪所产仔猪在70日龄时比对照品系公猪所产仔猪重2.1千克，差异显著（P<0.05）。选择品系母猪所产仔猪出生时轻0.11千克（P<0.10），21日龄时轻0.3千克（P<0.10），但从70日龄到屠宰时生长速度快0.026千克/天（P<0.10），165日龄时重3.9千克（P<0.05），达到100千克的时间比对照品系母猪所产仔猪早7.0天（P<0.05）。选择品系公猪所产阉公猪的胴体在第10肋骨处的脂肪比对照品系公猪所产阉公猪的胴体厚0.29厘米，差异显著（P<0.10）。选择品系母猪所产仔猪的胴体大理石纹评分比对照品系母猪所产仔猪的胴体高0.31分，差异显著（P<0.05）；肌肉颜色评分高0.25分，差异显著（P<0.10）。选择增加70日龄体重可降低达到100千克的年龄，且不增加脂肪沉积。然而，100千克前的存活率降低。对200日龄体重进行群体选择有效地增加了70日龄体重，但100千克时的脂肪厚度也增加了。
