Behaviour of boars in semen-processing centres

The behaviour of 78 boars in three different semen-processing centres was continuously recorded for 72 h per boar, with respect to boars' age, season, management system of the semen-processing centre (AI station) and size of boar pens. During each 24-h period of observation, the boars spent, on average, 81% of their time lying, equivalent to about 19.5 h per day. Most behavioural patterns were influenced by the AI station or by the semen-processing centre×season interaction. The percentages of active lying and active plus passive lying were significantly lower and the frequency of engagement with bedding was higher (P<0.05) in one AI station compared with the other two stations. The circadian rhythm of lying behaviour and engagement with bedding was influenced by management factors, such as feeding and the provision of water and straw bedding. These differed between semen-processing centres. Pen size had only a significant influence on engagement with bedding.