Abstract: 【Objective】 This experiment was conducted to study the effects of early weaning transfer on piglet behavior, growth performance and blood indexes, and to explore the appropriate weaning transfer mode, so as to provide reference for improving the welfare level of piglets.【Method】 216 (half of castrated male and female) Duroc×Large White×Yorkshire piglets with good health and similar weight (6.98 kg±0.63 kg) were randomly divided into three groups (there were 6 litters in each group and 12 heads in each litter).Group Ⅰ was control group, piglets did not wean or transfer into herds.Group Ⅱ was weaned transfer group, piglets did wean and transfer into herds.Group Ⅲ was weaned non-transfer group, piglets did wean but not transfer into herds.Early weaning was carried out at 21 days of age, and the experimental period was 14 days.During the experiment, the behavior performance, skin injury, mortality and diarrhea rate of piglets were observed and recorded, the blood of piglets was collected, and the serum cortisol and immune indexes were measured.【Result】 Compared with the control group, the feeding, resting and playing behaviors of piglets in groups Ⅱ and Ⅲ decreased significantly (P<0.01), and inquiry, solitude, wailing, huddling, aggression and phobia behaviors were extremely significantly increased (P<0.01).3-5 days after treatment, the degree of skin damage of piglets was extremely significantly higher than that of control group (P<0.01).The piglets in group Ⅱ had significantly lower body weight and average daily gain at 35 days of age than control group (P<0.05), and extremely significantly higher diarrhea rate than control group and group Ⅲ (P<0.01).The order of piglet mortality among groups was group Ⅰ(0)P<0.01), but the cortisol concentration in group Ⅲ was extremely higher than that in control group and extremely lower than that in group Ⅱ at 3 and 5 days after weaning and transfer (P<0.01).The concentration of immunoglobulin A (IgA) and immunoglobulin G (IgG) in groups Ⅱ and Ⅲ were extremely significantly lower than that in control group on the 7th day (P<0.01).The concentrations of interleukin-12 (IL-12) and interferon-γ (IFN-γ) were not significantly different among three groups (P>0.05).【Conclusion】 Early weaning not only affected the behavior, the concentration of cortisol and immunity of piglets, but also leaded to the decline of growth performance, the increase of skin damage, mortality and diarrhea rate.However, the stress of early weaning without transfer on piglets was significantly lower, which could reduce the adverse effects on piglets.

Key words: weaned piglets; transfer stress; behavior; growth performance