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Abstract

Stress and recognition of humans in weanling piglets. This study was aimed at investigating whether after weaning, piglets recognize persons that have handled them aversively during the lactation period, and whether such treatment intensifi es the stress of weaning. Before weaning, five litters received aversive handling treatment involving an aggressive and intimidating voice; six litters were treated conventionally. After weaning, the piglets’ behavior was compared in a series of tests. Compared to day 10 after weaning, in the fi rst two days after weaning higher frequencies of escape attempts, vocalizations, and standing and sitting, accompanied by a lower frequency of feeding (p<0.05), were observed in both treatments. The piglets handled aversively showed a higher frequency of escape attempts, walking, and interaction with other piglets (p<0.05). In a test carried out individually with the piglets of the aversive treatment, an unknown experimenter was able to approach the piglets closer than the aversive experimenter (p<0.001). In a further test, only 36% of the piglets handled aversively approached the aversive experimenter spontaneously. In contrast, 61% approached the unknown experimenter spontaneously (p < 0.02). In conclusion, at four to five weeks of age piglets can recognize a person that has handled them aversively during the lactation period. The behavior of piglets at weaning indicates that this management is a signifi cant source of stress and that aversive handling treatment during lactation increases this effect.