Wang Zhen, Shi Zhengxiang, Li Hao, Liu Hui, Xiao Zhaowei, Wang Hao, Pu Shihua
College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China.
Chongqing Academy of Animal Sciences, Chongqing 402460, China.
Animals (Basel). 2024 Jul 31;14(15):2229. doi: 10.3390/ani14152229.
Aggression in farm animals affects welfare. Although one-on-one aggression was studied, group-on-individual aggression remains unresolved. This study aimed to examine how herd establishment times and structures influence aggression intensity (AI) of herds towards unfamiliar pigs. Six groups of pigs were established, with a new pig added every three days. AI was measured by skin lesion severity on the new pigs. A parabolic model based on the Levenberg-Marquardt algorithm and conjoint analysis identified factors influencing AI. Results show AI was not significantly affected by herd size but was significantly influenced by the number of pens ( < 0.01). AI showed a significant association with elevated time (T) since the establishment of the herd in six pig herds (Kendall's tau-τ = 0.976, < 0.001). The effect of T on the AI became stronger as T increased, which was consistently validated in six pig herds. Furthermore, the interaction effect indicates a significant difference in AI between herds formed with two pens and those with more than two pens when T ≤ 12 ( < 0.05). However, as T increased beyond 12, the number of pens used to form the herd did not significantly affect AI. These findings highlight the complex interactions between herd establishment time and structural composition in shaping aggression intensity towards unfamiliar pigs.
农场动物的攻击性会影响其福利。尽管一对一的攻击性已得到研究，但群体对个体的攻击性仍未得到解决。本研究旨在探讨畜群建立时间和结构如何影响畜群对陌生猪的攻击强度（AI）。建立了六组猪群，每三天添加一头新猪。通过新猪的皮肤损伤严重程度来测量AI。基于Levenberg-Marquardt算法和联合分析的抛物线模型确定了影响AI的因素。结果表明，AI不受畜群规模的显著影响，但受猪栏数量的显著影响（<0.01）。在六个猪群中，AI与畜群建立后的时间（T）呈显著正相关（肯德尔tau-τ = 0.976，<0.001）。随着T的增加，T对AI的影响变得更强，这在六个猪群中得到了一致验证。此外，交互作用表明，当T≤12时，由两个猪栏组成的畜群和由两个以上猪栏组成的畜群之间的AI存在显著差异（<0.05）。然而，当T超过12时，用于组建畜群的猪栏数量对AI没有显著影响。这些发现突出了畜群建立时间和结构组成在塑造对陌生猪的攻击强度方面的复杂相互作用。
