Veterinary Medice Departament, Universidade Estadual de Londrina, Highway Celso Garcia Cid (PR 445), Km 380, Londrina, Parana, Brazil.
Zootecnia Department, Universidade Estadual de Londrina, Highway Celso Garcia Cid (PR 445), Km 380, Londrina, Parana, Brazil.
Animal. 2021 Jan;15(1):100072. doi: 10.1016/j.animal.2020.100072. Epub 2020 Dec 16.
Boar rearing, which avoids pain and suffering caused by surgical castration, provides better performance, a greater deposition of muscle tissue and leaner carcasses and thus has beneficial effects on both animal welfare and the product. Some countries that do not slaughter boars must consider their boar taint and aggressive and sexual behaviours. Considering that pigs are housed in large groups, which may complicate the formation of social hierarchies and increase fighting and mounting behaviours, some studies have conducted research with reduced numbers of pigs per pen, but these behaviours continued to be observed. However, a study of the reproductive status of pair-housed male pigs has yet to be reported. The aim of this study was to determine whether the reproductive status of uncastrated, immunocastrated and surgically castrated pair-housed male pigs alters their natural, agonistic and sexual behaviours. A total of 48 male pigs from Agroceres PIC™ genetics were assigned to three groups: surgically castrated (barrows), immunocastrated and uncastrated (boars). Natural, aggressive and sexual behaviours of the pigs were assessed by direct observations during four periods of 12 h each (six, five and three weeks before slaughter and the slaughter week). The pigs were housed in pairs from the growing phase until slaughter. Animal behaviour was observed from the finishing phase to slaughter. Carcass lesions were assessed according to five different classes (one: no injury; two to five: severely injured). Overall, boars spent more time lying and less time eating and drinking than barrows. In total of all the periods (48 h), boars expressed more aggressive and sexual behaviours than barrows, whereas immunocastrated pigs displayed similar behaviours to boars, before and after the second vaccine dose. No differences in carcass lesions between treatments and no prevalence of carcasses with severe injuries were observed. In conclusion, the reproductive status of pair-housed male pigs did not change the natural behaviour of boars, immunocastrated pigs or barrows. The agonistic and sexual behaviours of boars and barrows remained unchanged. When housing pigs in pairs, immunocastrated pigs presented similar agonistic and sexual behaviours to boars before and after the second immunocastration vaccine dose. The use of pair-housed uncastrated male pigs has generated welfare benefits for these animals, as the number of carcasses with injuries did not differ from barrows and immunocastrated pigs.
公猪养殖避免了去势手术带来的疼痛和痛苦，可提高性能、增加肌肉组织沉积和减少体脂，从而对动物福利和产品都有益。一些不屠宰公猪的国家必须考虑公猪的腥味、攻击性和性行为。考虑到猪被饲养在大群体中，这可能会使社会等级制度复杂化，并增加战斗和交配行为，因此一些研究减少了每栏的猪数量，但这些行为仍在继续观察到。然而，关于配对饲养的公猪生殖状态的研究尚未报道。本研究旨在确定未去势、免疫去势和手术去势的配对饲养公猪的生殖状态是否会改变它们的自然、攻击和性行为。总共 48 头来自 Agroceres PIC™ 遗传的雄性猪被分配到三个组：手术去势（阉猪）、免疫去势和未去势（公猪）。通过在屠宰前六周、五周和三周以及屠宰周的四个 12 小时周期内进行直接观察，评估了猪的自然、攻击和性行为。猪从生长阶段开始就成对饲养，直到屠宰。从育肥阶段到屠宰期间观察动物行为。根据五个不同的等级（一：无损伤；二到五：严重损伤）评估胴体损伤。总的来说，与阉猪相比，公猪躺着的时间更多，而吃和喝的时间更少。在所有周期（48 小时）中，公猪的攻击性和性行为都比阉猪多，而免疫去势猪在第二次疫苗接种前后的行为与公猪相似。在处理之间未观察到胴体损伤的差异，也未观察到严重损伤的胴体的流行。总之，配对饲养的公猪的生殖状态并没有改变公猪、免疫去势猪或阉猪的自然行为。公猪和阉猪的攻击和性行为保持不变。当猪成对饲养时，免疫去势猪在第二次免疫去势疫苗接种前后的攻击性和性行为与公猪相似。使用配对饲养的未去势公猪为公猪带来了福利益处，因为受伤的胴体数量与阉猪和免疫去势猪没有差异。
