SRUC (Scotland's Rural College), West Mains Road, Edinburgh, Scotland EH9 3JG, UK.
PIC Europe, C/Pau Vila, 22 2o piso, 08174, Sant Cugat del Valles, Barcelona, Spain.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad070.
This study estimated the genetic parameters for human-directed behavior and intraspecific social aggression traits in growing pigs, and explored the phenotypic correlations among them. Data on 2,413 growing pigs were available. Pigs were mixed into new social groups of 18 animals, at 69 ± 5.2 d of age and skin lesions (SL) were counted 24 h (SL24h) post-mixing. Individual behavioral responses to isolation in a weighing crate (CRATE) or when alone in an arena while a human directly approached them (IHAT) were assessed within 48 h post-mixing. Additionally, pigs were tested for behavioral responses to the presence of a single human observer walking in their home pen in a circular motion (WTP) within one (T1) and 4 wk post-mixing (T2) noting pigs that followed, nosed or bit the observer. Animal models were used to estimate genetic and phenotypic parameters for all studied traits. Heritabilities (h2) for SL, CRATE and IHAT responses were low to moderate (0.07 to 0.29), with the highest h2 estimated for speed of moving away from the approaching observer. Low but significant h2 were estimated for nosing (0.09) and biting (0.11) the observer at T2. Positive high genetic correlations (rg) were observed between CRATE and IHAT responses (0.52 to 0.93), and within SL traits (0.79 to 0.91) while positive low to high correlations between the estimated breeding values (rEBV) were estimated within the WTP test (0.24 to 0.59) traits. Positive moderate rg were observed between CRATE and central and posterior SL24h. The rEBV of CRATE and IHAT test responses and WTP test traits were low, mostly negative (-0.21 to 0.05) and not significant. Low positive rEBV (0.06 to 0.24) were observed between SL and the WTP test traits. Phenotypic correlations between CRATE and IHAT responses and SL or WTP test traits were mostly low and not significant. Under the conditions of this study, h2 estimates for all studied traits suggest they could be suitable as a method of phenotyping aggression and fear/boldness for genetic selection purposes. Additionally, genetic correlations between aggression and fear indicators were observed. These findings suggest selection to reduce the accumulation of lesions is likely to make pigs more relaxed in a crate environment, but to alter the engagement with humans in other contexts that depends on the location of the lesions under selection.
本研究旨在评估生长猪的行为和种内社会攻击特征的遗传参数，并探讨它们之间的表型相关性。研究数据来自 2413 头生长猪。在 69±5.2 日龄时，将猪混合到新的社会群体中，24 小时后（SL24h）记录皮肤损伤（SL）。在混合后 48 小时内，通过隔离在称重箱（CRATE）或独自在竞技场中当人类直接接近它们时（IHAT）评估个体对隔离的行为反应。此外，当单个人类观察者在他们的猪圈中以圆形运动（WTP）行走时，猪被测试对存在的行为反应，记录跟随、嗅探或咬观察者的猪。使用动物模型估计所有研究性状的遗传和表型参数。皮肤损伤、CRATE 和 IHAT 反应的遗传力（h2）为低至中等（0.07 至 0.29），最高的 h2 估计为远离接近观察者的速度。在 T2 时，对观察者进行嗅探（0.09）和咬（0.11）的低但显著的 h2 也得到了估计。CRATE 和 IHAT 反应之间存在正的高遗传相关性（rg）（0.52 至 0.93），以及 SL 性状内（0.79 至 0.91），而在 WTP 测试内（0.24 至 0.59）性状中，估计的育种值（rEBV）之间存在正的低至高相关性。在 CRATE 和中央及后部 SL24h 之间观察到正的中度 rg。CRATE 和 IHAT 测试反应和 WTP 测试性状的 rEBV 较低，主要为负（-0.21 至 0.05）且不显著。在 SL 和 WTP 测试性状之间观察到低正 rEBV（0.06 至 0.24）。CRATE 和 IHAT 反应与 SL 或 WTP 测试性状之间的表型相关性大多较低且不显著。在本研究的条件下，所有研究性状的 h2 估计表明，它们可能适合作为遗传选择目的的攻击性和恐惧/大胆性表型的方法。此外，还观察到攻击性和恐惧指标之间的遗传相关性。这些发现表明，选择减少病变的积累可能会使猪在 CRATE 环境中更加放松，但要改变在其他情况下与人类的接触，这取决于选择下病变的位置。
