Behaviour and health of entire male pigs in a semi-natural habitat

Summary in the original language of the document

Entire male pigs in commercial housing systems are known for their increased agonistic and sexual behaviour. In wild boars, young males remain with the family group for about a year, then live in bachelor groups for approximately another year. The behaviour of domestic entire male pigs in family groups under semi-natural conditions has not been described to date. We therefore observed the behaviour of young pigs (Swiss Large White) in a 1.9 ha enclosure including pasture and forest. The social group consisted of three sows and their 41 piglets. Three months after birth, the group of piglets was reduced to 12. Pigs were observed once per week during four hours from an age of one month until slaughter at about 5.5 months. Our protocol included scan and continuous sampling through direct observations. We observed a higher frequency of head knocks between males or between males and females compared to between females. Fights were mostly observed between males, and rarely involved females. Mounting behaviour was performed nearly exclusively by males, with an observed drift in preference of the recipient: While in the beginning the recipients were similarly males and females, males mounted females significantly more than other males after three months of age. The prevalence of skin lesions was low and similar between males and females. In total 3 female and 3 male pigs were assessed as lame at least once. No penile injuries were observed at slaughter. These observations made under semi-natural conditions are in accordance with the described behaviour of entire males in housing systems.