Dalmau Antoni, Martínez-Macipe Míriam, Manteca Xavier, Mainau Eva
Institute of Agrifood Research and Technology (IRTA), Animal Welfare Program, Girona, Spain.
Universitat Autònoma de Barcelona (UAB), Veterinary School, Campus Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
Front Vet Sci. 2020 Dec 3;7:600259. doi: 10.3389/fvets.2020.600259. eCollection 2020.
The aim of the present work was to study group size, group composition and habitat use of Iberian pigs along the year when reared outdoor. This consists of a regimen in which animals are reared free range from 2 months of age until at least 14 months of age. In a first stage, animals are supplemented with concentrates, and in a second, called montanera, pigs eat just natural resources in areas with no more than two pigs per hectare. In these systems, males are castrated to avoid boar taint and females spayed to avoid the attraction and mounting by wild boars. The study was carried out in five different farms allocated in the south-west of Spain during 2 consecutive years, from March 2012 to February 2014, under the montanera regimen, and with a total of 995 animals observed (498 males and 497 females). The data were analyzed with SAS by means of general models and proc mixed. Mean group size along the year was of 17 ± 12.9 individuals, but this was significantly lower ( < 0.05) during the montanera (12 ± 0.8) and at midday (13 ± 0.8). Groups were bigger ( < 0.05) when they were more than 50 m from a tree (23 ± 1.8), or <10 m from the shelter (25 ± 1.5), the feeding area (31 ± 3.1) and the water-bath area (25 ± 1.5). Nine percent of the groups were solitary animals, being higher ( = 0.0286) during the montanera (11%) than the rest of the year (8%) and being formed in 68% by males. Males were less involved in mixed groups than were females (75% vs. 91%), especially in spring, where the largest ( < 0.0001) male groups were found. Female groups were less frequent and smaller ( < 0.0001) than were male and mixed groups. In conclusion, although males were castrated at a very young age, they showed a different behavior than females, forming in bachelor groups during the spring and being less involved in mixed groups and with more solitary animals. During the montanera, when animals were feeding on acorns and other natural resources, groups were smaller and closer to the trees, solitary males reaching a maximum percent.
本研究的目的是调查伊比利亚猪在户外饲养全年的群体规模、群体组成和栖息地利用情况。这种饲养方式是让动物从2月龄开始直至至少14月龄自由放养。在第一阶段，动物会补充浓缩饲料，在第二阶段，即所谓的“蒙塔涅拉”阶段，猪只仅食用自然资源，且每公顷区域内猪的数量不超过两头。在这些养殖系统中，雄性猪会进行阉割以避免公猪异味，雌性猪会进行绝育以避免被野猪吸引和骑跨。本研究于2012年3月至2014年2月的连续两年间，在西班牙西南部的五个不同农场按照“蒙塔涅拉”养殖方式开展，共观察了995头猪（498头雄性和497头雌性）。数据通过SAS软件利用通用模型和混合过程进行分析。全年平均群体规模为17±12.9头个体，但在“蒙塔涅拉”阶段（12±0.8）和中午时段（13±0.8）显著更低（<0.05）。当群体距离树木超过50米（23±1.8）、距离庇护所<10米（25±1.5）、距离采食区（31±3.1）和水浴区（25±1.5）时，群体规模更大（<0.05）。9%的群体为单独个体，在“蒙塔涅拉”阶段（11%）高于一年中的其他时段（8%），且68%由雄性组成。雄性参与混合群体的程度低于雌性（75%对91%），尤其是在春季，此时发现了最大规模（<0.0001）的雄性群体。雌性群体比雄性群体和混合群体出现频率更低、规模更小（<0.0001）。总之，尽管雄性猪在很小的时候就被阉割，但它们表现出与雌性不同的行为，在春季形成单身群体，参与混合群体的程度较低且单独个体的比例更高。在“蒙塔涅拉”阶段，当动物以橡子和其他自然资源为食时，群体规模更小且更靠近树木，单独雄性个体的比例达到最高。
