Effects of two different early socialization models on social behavior and physiology of suckling piglets
Early socialization not only facilitates positive behaviors and cognition abilities of post-weaning piglets, but also has effects on social behavior and physiology of suckling piglets during the lactation. Therefore, this study aimed to investigate the effects of early socialization environment on social behavior, stress coping and weaning weight of suckling piglets. We selected 199 piglets (Large White × Duroc × Min pig) from 18 litters and three treatments were differentiated: intermittent contact group (IC, 6 litters), piglets of two neighboring litters were socialized twice a week for 3 h from D14 (14 days of age) to D35; continuous contact group (CC, 6 litters), piglets of two neighboring litters were socialized continuously from D14 to D35; the control group (CON, 6 litters), piglets were not socialized during the lactation. Behavioral observation occurred on D14, D15, D21, D22, D28, D29, D33 and D34, and blood samples were collected on D16, D28 and D34. The results revealed that the amount of fighting and head knocking in IC group was higher than CC and CON groups (P < 0.05). On the social interaction during the lactation, for performing piglet, piglets in CC group showed more oral-nasal contact than IC in 3 weeks of age (W3, D21 and D22) (P = 0.045), and socialized groups (CC, IC) showed more oral-nasal contact than CON in W4 (P = 0.001). The amount of mounting in CC was higher than IC and CON from W3 to W5 (P < 0.001). For receiving pig, amounts of avoiding behavior in IC and CC were higher than CON in W4 (P = 0.047). The return approach (positive response to the performing pig) of IC and CC were higher than C in W2, CC was higher than IC and CON in W3 (P = 0.003), socialized groups were higher than CON in W4 and W5 (P < 0.001). Serum epinephrine concentration in IC and CC were lower than CON on D16 (P < 0.001). The brain-derived neurotrophic factor (BDNF) concentration of IC was higher than CC and CON (P < 0.05) on D16 and D28, IC and CC were higher than CON (P = 0.004) on D34. There was no significant difference in weaning weight and cross-sucking frequency among treatments. In conclusion, the early socialization environment provided opportunities for piglets to improve their social skills, increased the expression of social behaviors and had a positive impact on the expression of BDNF in piglets.
|Publication Title||Applied Animal Behaviour Science|
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