Turner S P, Roehe R, D'Eath R B, Ison S H, Farish M, Jack M C, Lundeheim N, Rydhmer L, Lawrence A B
Sustainable Livestock Systems Group, Scottish Agricultural College, Edinburgh, EH9 3JG, UK.
J Anim Sci. 2009 Oct;87(10):3076-82. doi: 10.2527/jas.2008-1558. Epub 2009 Jul 2.
The objective of the study was to estimate genetic correlations between skin lesions and aggressive behavior postmixing and under more stable social conditions as a potential means of selecting against pig aggressiveness. Postmixing aggression in commercial pig production is common, compromises welfare and profitability, and cannot be significantly reduced by low-cost changes to the environment. A genetic component to individual aggressiveness has been described in pigs and other species. Selective breeding against aggressiveness ought to be possible if an easily measured indicator trait can be shown to be genetically associated with aggressive behavior. Aggressive behavior was recorded continuously for 24 h after mixing, and a count of skin lesions (lesion count, LC) was recorded at 24 h and 3 wk postmixing on 1,663 pigs. Two behavioral traits were found to have a moderate to high heritability similar to that of growth traits; duration of involvement in reciprocal fighting (0.43 +/- 0.04) and delivery of nonreciprocal aggression (NRA; 0.31 +/- 0.04), whereas receipt of NRA had a lower heritability (0.08 +/- 0.03). Genetic correlations (r(g)) suggested that lesions to the anterior region of the body 24 h after mixing were associated with reciprocal fighting (r(g) = 0.67 +/- 0.04), receipt of NRA (r(g) = 0.70 +/- 0.11), and to a lesser extent, delivery of NRA (r(g) = 0.31 +/- 0.06). Lesions to the center and rear were primarily genetically associated with receipt of NRA (r(g) = 0.80 +/- 0.05, 0.79 +/- 0.05). Genetic correlations indicated that pigs that engaged in reciprocal fighting delivered NRA to other animals (r(g) = 0.84 +/- 0.04) but were less likely to receive NRA themselves (r(g) = -0.41 +/- 0.14). A genetic merit index using lesions to the anterior region as one trait and those to the center or rear or both as a second trait should allow selection against animals involved in reciprocal fighting and the delivery of NRA. Positive correlations between LC 24 h and 3 wk after mixing were found, especially for lesions to the center and rear of the body, indicating that postmixing lesions are predictive of those received under more stable group conditions. As well as reducing immediate aggression at mixing, selection on postmixing LC is expected to have a long-term impact on injuries from aggression, even after dominance relationships are established.
本研究的目的是估计皮肤损伤与混群后以及在更稳定的社会条件下攻击行为之间的遗传相关性，作为选择对抗猪攻击性的一种潜在手段。在商业养猪生产中，混群后的攻击行为很常见，会损害福利和盈利能力，并且通过低成本的环境改变无法显著降低。猪和其他物种中已经描述了个体攻击性的遗传成分。如果能证明一个易于测量的指示性状与攻击行为存在遗传关联，那么针对攻击性进行选择性育种应该是可行的。对1663头猪在混群后连续24小时记录攻击行为，并在混群后24小时和3周记录皮肤损伤计数（损伤计数，LC）。发现两个行为性状具有中度到高度的遗传力，与生长性状相似；相互打斗的持续时间（0.43±0.04）和非相互攻击（NRA）的发生频率（0.31±0.04），而遭受NRA的遗传力较低（0.08±0.03）。遗传相关性（r(g)）表明，混群后24小时身体前部的损伤与相互打斗（r(g)=0.67±0.04）、遭受NRA（r(g)=0.70±0.11）以及在较小程度上与NRA的发生频率（r(g)=0.31±0.06）相关。身体中部和后部的损伤主要与遭受NRA存在遗传关联（r(g)=0.80±0.05，0.79±0.05）。遗传相关性表明，参与相互打斗的猪会对其他动物实施NRA（r(g)=0.84±0.04），但它们自己遭受NRA的可能性较小（r(g)=-0.41±0.14）。使用身体前部的损伤作为一个性状以及身体中部或后部或两者的损伤作为第二个性状的遗传价值指数，应该能够选择出不参与相互打斗和实施NRA的动物。发现混群后24小时和3周的LC之间存在正相关，特别是身体中部和后部的损伤，这表明混群后的损伤可以预测在更稳定的群体条件下遭受的损伤。除了减少混群时的即时攻击外，对混群后LC进行选择预计对攻击造成的伤害有长期影响，即使在优势关系建立之后。
