Sow responsiveness to human contacts and piglet vocalization during 24 h after onset of parturition

Abstract

Sow responsiveness towards external disturbances and concurrent postural changes are proposed to be an important cause of early piglet crushing. The aim of the present study was to assess whether loose housed sows change their responsiveness over time within the first 24 h after birth of the first piglet upon exposure to different types of human contact and towards piglets’ scream. The responsiveness of the sows ( n = 17) was scored during: (i) blood sampling of the sow during 24 h after the onset of parturition, (ii) human handling of a piglet at 0, 30 min, 1, 2, 4, 8 and 24 h after birth, (iii) screaming when a piglet was trapped underneath the sow and (iv) exposure to playback of piglets’ screams at 10 and 24 h after the onset of parturition. A sow was scored as responsive if she changed her posture in response to the stimuli. The behavioral scores were analyzed during three predefined periods: parturition (from birth of first piglet to birth of last piglet), phase 1 (from birth of last piglet to 12 h after birth of first piglet) and phase 2 (from 12 h after birth of first piglet to 24 h after birth of first piglet). The responsiveness of sows towards humans during blood sampling differed between the three periods ( p < 0.01), whereas it did not differ between periods during human handling of piglets. During blood sampling, fewer sows were responsive during phase 1 (5%) compared to during parturition (11%) and the later phase 2 (17%). We did not detect any temporal changes in sow responsiveness towards natural incidences of screaming of own trapped piglet between the three periods (it remained high: 80%), whereas sows exposed to playback of piglet screams had a higher probability ( p < 0.05) to react at 12 h (50%) than at 24 h (25%). In conclusion, the responsiveness of sows toward direct human contact was lower during the first 12 h postpartum. The careful handling of piglets in the home pen had a minimal effect on the probability of postural changes in sows. However, sows were highly reactive towards the screaming of own trapped piglet during the whole 24 h period pp. The relative lower responsiveness towards playbacks, decreasing from 12 to 24 h pp, cast doubt upon the piglet scream playback test as a useful approach to evaluate maternal responsiveness in sows.