The importance of social stability and its influence on the expression of the social behaviour repertoire in domestic animals remains poorly understood, especially for affiliative behaviours and other putative socio-positive behaviours such as social play. This study investigated the occurrence and type of social behaviours, with a focus on socio-positive behaviours, and their relation to growth and welfare indicators within groups of littermates vs. groups composed of pigs from several litters and initially unfamiliar to each other. We hypothesised that pigs kept with littermates would show more positive social interactions than pigs socially mixed after weaning, and that social interactions would change over time as mixed groups progressively regained social stability. The behaviour of 14 groups of indoor-housed weaned pigs (7 groups per treatment; 8–14 pigs per group) was observed from the day after weaning (4 weeks of age) and thereafter once per week until the seventh week using scan sampling (48 scans per individual per day) and continuous observations (30 min per group per day). Pigs spent most time lying together (on average 50 % of the scans) or performing non-social behaviours (31 % of scans). Exploring together was the most common social activity, observed in 7.32 % of scans. Other social behaviours occurred infrequently and each accounted for only 0.04%–1.09% of scans. Treatment significantly influenced mounting behaviour, with more mounting between pigs in the mixed groups as compared to littermate groups (0.52 % vs. 0.27 % of scans, respectively; P = 0.03). Other behaviours did not differ between treatments or the interaction of treatment and day. Nosing proximity, social play, exploring together, and oral manipulation of conspecifics varied between days (i.e. age; all P < 0.01). Pigs in littermate groups showed a better growth rate over the seven days after weaning (littermates: 1.03 ± 0.11 kg vs. mixed: 0.78 ± 0.11 kg; P = 0.01). In conclusion, socio-positive behaviours were more prevalent than socio-negative behaviours overall, supporting that positive social interactions may be an important but overlooked aspect of social life. Groups of littermates did not show more positive social behaviour than mixed groups, but they did show less mounting behaviour and seemed less affected by the stress caused by weaning.

社会稳定的重要性及其对家畜中社会行为表述的影响仍然知之甚少，特别是对于亲属行为和其他假定的社会积极行为（如社会游戏）而言。这项研究调查了社会行为的发生和类型，重点是社会积极行为，以及它们与同窝仔和成年仔群体内的增长和福利指标之间的关系。。由几窝猪组成，最初彼此不熟悉的猪群。我们假设饲养同窝仔猪的猪比断奶后在社会上交往的猪表现出更多的积极社交互动，并且随着交往群体逐渐恢复社会稳定，社交互动会随着时间而改变。从断奶后的第二天（4周龄）开始，观察到14组室内饲养的断奶猪（每处理7组；每组8–14头猪）的行为，此后每周一次，直到第七周使用扫描采样（每人每天48次扫描）和连续观察（每组每天30分钟）。猪大部分时间躺在一起（平均占扫描的50％）或进行非社交行为（占扫描的31％）。共同探索是最常见的社交活动，占扫描的7.32％。其他社交行为很少发生，每种仅占扫描的0.04％–1.09％。治疗显着影响坐骑行为，与同窝组相比，混合组猪之间的坐骑更多（0.52％与。分别为扫描的0.27％；P = 0.03）。其他行为在治疗之间或治疗与日间交互作用方面没有差异。不同日子之间的贴近度，社交活动，共同探索和口服操作都不同（即年龄；所有P <0.01）。在断奶后的七天内，同窝组的猪表现出更好的生长速度（同窝组：1.03±0.11 kg vs。混合：0.78±0.11公斤; P = 0.01）。总之，社会积极行为比社会消极行为更为普遍，这表明积极的社会互动可能是社会生活中一个重要但被忽视的方面。同窝组的人没有比混合组更积极的社交行为，但是他们的确表现出较少的坐骑行为，而且似乎受断奶压力的影响较小。