van der Steen H A, Schaeffer L R, de Jong H, de Groot P N
Anim. Breed. Dept., Agricultural University, Wageningen, The Netherlands.
J Anim Sci. 1988 Feb;66(2):271-9. doi: 10.2527/jas1988.662271x.
Sows, especially primiparous, may show aggressive behavior at parturition against their own piglets, resulting in wounding or death of the piglets. Frequency, environmental influences and heritability of aggressive behavior were studied in two data sets. The first (923 first litters) was collected at an experimental farm and the other (925 first litters) came from a pig breeding organization. Frequency of aggressiveness ranged, depending on its definition, from 7 to 12%. Fixed effects of year, season and feeding level of the gilt during the rearing period did not affect the frequency of aggressiveness. A regression of aggression on postpartum sow weight was found, suggesting that low weight at first farrowing might predispose sows to aggressive behavior. Coefficients for backfat and litter size were positive but nonsignificant. Heritability of aggressiveness on the underlying normal scale, estimated from the paternal half-sib component of variance, averaged .12 for the first data set, and .25 for data set II. Estimates from daughter-dam regression were .49 and .87 for the two data sets, respectively. A simulation study indicated that this difference might be due to maternal effects. A simple application would be to select boars and gilts from non-aggressive sows only. Response to selection would be rather slow if the frequency of aggressive behavior is low. At frequencies that are too high from an economic point of view, estimation of breeding values, combining own performance and(or) data from relatives, is required.
母猪，尤其是初产母猪，在分娩时可能会对自己的仔猪表现出攻击行为，导致仔猪受伤或死亡。在两个数据集中研究了攻击行为的发生频率、环境影响和遗传力。第一个数据集（923窝头胎仔猪）来自一个实验农场，另一个数据集（925窝头胎仔猪）来自一个养猪育种组织。根据攻击行为的定义不同，其发生频率在7%至12%之间。饲养期内年份、季节和后备母猪饲养水平的固定效应不影响攻击行为的发生频率。发现攻击行为与产后母猪体重之间存在回归关系，这表明头胎分娩时体重较低可能使母猪易发生攻击行为。背膘厚度和产仔数的系数为正，但不显著。根据父本半同胞方差分量估计，在潜在正态分布尺度上，攻击行为的遗传力在第一个数据集中平均为0.12，在第二个数据集中为0.25。两个数据集通过女儿-母亲回归得到的估计值分别为0.49和0.87。一项模拟研究表明，这种差异可能是由于母体效应。一个简单的应用是只从不具攻击性的母猪中选择公猪和后备母猪。如果攻击行为的发生频率较低，选择反应会相当缓慢。从经济角度来看，当攻击行为发生频率过高时，需要结合自身表现和（或）亲属数据来估计育种值。
