Short- and medium-term effects of different types of sounds on the behaviour of gestating sows | Effets à court et moyen terme de différents types de sons sur le comportement de truies gestantes

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anglais. Short-and medium-term effects of different types of sounds on the behaviour of gestating sows Noise can alter the behaviour and welfare of pigs, although they have good adaptive abilities. The objective of this study was to determine the relationship between different regularly emitted sounds and the behaviour of gestating sows, as well as their habituation time to these sounds. Two groups of gestating sows (n = 15 and 17) were observed during a resting period ("PM", 1:30-6:30 pm) and a feeding period ("night", 11:00 pm-4:00 am) on Monday ("Test 1") and Wednesday ("Test 2"-only for one group of sows) of a Test week during which four types of sounds (i.e. alarms, animals, metallic, human voices) were emitted randomly every 10 minutes. A "Base" week during which no sound was emitted preceded the Test week. Sows' location in the room, posture, activity and social interactions were manually analysed by video. During Test 1, the time spent sleeping decreased compared to Base (PM:-8 min, night:-44 min) as well as the number of posture changes (-10 to 30 changes regarding group and period). For one group, changes of activity also increased in Test 1 compared to Base (+ 27 changes). During Test 2, the time spent sleeping increased of 36 min compared to Test 1 and of 12 min compared to Base. The number of changes of posture kept decreasing (86.7 vs 57.4 vs 26.1 changes for Base, Test 1 and Test 2 respectively), and the number of activity changes decreased (-27 changes, P = 0.04). During PM Test 1, the time spent lying was 6 to 10% more important with human sounds than with the other sounds. The sows quickly adapted to the sounds as they recovered their basal activity on the second test day, regardless of sound type.