Effects Of Early Social Environment On Emotion And Welfare Of Calf

In order to provide the basis for scientific management of calf-rearing.This article aims to explore the emotional behavior, physiology, immunity indicators of calf and the effect of different early social environments on emotion and welfare were explored in this study.Experiment 1 was to measure the emotional indicators of calves.Twelve 30-day-old Holstein calves in similar weight were selected and randomly divided into two treatments(6 replicates per treatment, 1 calf per replicate). Getting or not getting feed while starving calves saw feed were chosen as positive and negative stimuli to reveal the reaction of calves in the positive and negative emotional states.Saliva and blood were selected immediately and 15-minute behavioral observation was performed after stimulate. The results showed: the play behavior of the calves received in positive stimulation group was higher significantly than that in negative stimulation group(P<0.05), positive stimuli performed significantly less self-grooming(P<0.05), headshaking(P<0.05) and tongue-rolling(P<0.05) of calves than negative stimuli, but there is no significant differences in exploratory behavior between two groups. Cortisol levels after stimulation(P<0.05) and heart rate(P<0.05)increased significantly after positive stimulate, but the level of salivary amylase enzyme lowered significantly(P<0.05).The cortisol level, salivary amylase Enzyme level and heart rate(P<0.05) increased significantly after negative stimulation. Positive emotional stimuli significantly improved NK cell activity(P<0.05),negative emotional stimuli did the opposite(P<0.05),but there was no significant effect on Ig A, Ig G and SIg A in both groups. The level of TNF-α was significantly lower before stimulation than after positive stimulus(P <0.05), negative stimuli significantly increased TNF-α level(P <0.05), there is no significant difference on IL-2, IL-3, IL-6 between stimulation.Experiment 2 was to explore the impact of early social environment on emotion and welfare of calves. 132 healthy Holstein calves with similar age and weight selected received colostrum within four hours after birth, then they were divided into 4 treatment(single group S, 3-calf group G3,6-calf group G6,12-calf group G12), six repeats was in each treatment.The behavioral indicators were tested in the day15,30,45, the performance in day16,31,46, physiology, immune parameters in day16,31,46 and day 50(the day of mixing)The results showed :Social environment had a significant effect on self-grooming, allogrooming, social play,exploring, cross sucking, tongue-rolling of calves(P <0.05); self-grooming, allogrooming, social play, exploring of group-housed calves were significantly higher than that in single group, tongue-rolling in group-housed group were significantly lower than that in single group.Locomotive play of calves was increased as the group size.Heart rate of calves was significantly affected by social environment(P<0.05), heart rate in G12 was significantly higher than that in S.Social environment had no significant effect on cortisol level(P> 0.05), but after mixing, cortisol level in single group was significantly higher than that in group-housed groups.The effect of social environment on NK active, Ig G, Ig A, SIg A level of the calves was significant(P <0.05). The NK active in S and G3 groups was low and increased as the group size. Ig G, Ig A level of S and G3 groups was significantly higher than that of group G6, G12.After mixing, SIg A level in group S reduced significantly and was lower than the group-housed groups. The effect of social environment on IL-2, IL-3, IL-6, TNF-α level was significant(P<0.05).The levels of IL-2, IL-3 increased as group size. IL-6 level of group S, G3,G6 was significantly lower than that in group G12. The level of TNF-α in group S,G3 was lower.The social environment significantly affect weight, feed intake(P<0.05). The weight of group S,G3, G6 was significantly higher than that in group G12. The average intake of group S, G3 was significantly higher than that of group G6, G12. Social environmental had no significant effect on daily weight gain(P>0.05), the average daily gain of group S and G3 was higher. Social environment had a significant effect on body length, body height and heart girth(P<0.05). Group S, G6 had higher body length. Group S, G3 had significantly greater body height than group G6, G12; The heart girth of group G12 was significantly lower than that of other groups. Feces index and disease incidence increased with group size.Conclusion in this study,1:playing, selfgrooming, head-shaking, tongue-roll, exploratory behavior, cortisol, heart rate, salivary amylase, natural killer cell activity, TNF-α could be assessed as the indicatorsof emotional states.2:In terms of emotional and welfare level,G3,G6 seems more feasible than S and G12. The group housing could provide opportunities for socialization. The space increasing improved a high level of activity and play and strengthened ties with social groups. There are more benefits to a range of development of social behavior. Group housing improved the ability of calves to cope with the novel and stress and may provide advantages for subsequent growth of calves. The long-term effects of early social environment and whether the subsequent social experience extent could counteract these effects should be studied further.