Abstract: This experiment investigated the effects of feeding times of colostrum on performance of Jersey calves. Twenty healthy Jersey calves with similar birth weight were randomly divided into 4 groups:control group,experimental groups I,II and III,with 5 calves in each group and the experiment lasted for 60 days .Calves in the 4 groups were fed colostrum twice according to their weight on the day of birth. The first was fed after birth on 10.0% of body weight ,and the second was 5.0% of body weight 6~8 hours after birth. The calves in the 4 groups were raised in the calving area on the day of birth,and since the age of 2 days, they were all raised in hutches outside separately. After 2 days of age,calves in the control group were fed regular milk at 06:00 and 16:00 each day,1.50 L at 2~6 days of age,1.80 L at 7~20 days of age,2.50 L at 21~35 days of age,and 3.00 L at 36~60 days of age. And from 7 days of age,calves were free to take Calf grain . Experimental Groups:I,II and III,were fed colostrum until calves were 2,4 and 6 days of age, respectively,then regular milk. The feeding time and feeding quantity were the same as those of the control group. The results show that:(1)At 48 h,72 h,96 h after feeding of colostrum,there was difference in serum IgG between experimental group and control group(P < 0.05),and at 120 h,144 h,168 h after feeding,there was no significant difference in serum IgG content between experimental group I and control group(P > 0.05).The serum IgG content of test groups II and III was different from that of control (P< 0.01).(2)when feeding times of colostrum were increased ,the diarrhea incidence of calves at 20 days of age could be reduced. Compared with the control group,the diarrhea incidence of calves in groups I,II and III was reduced by 9.5,22.5 and 36.5 percentage point,respectively,and the cost of treating diarrhea of calves was decreased by 12.0 yuan,43.2 yuan and 76.8 yuan.The survival rate of calves in all experimental groups was 100.0%.(3) With the increase of colostrum feeding times,ADG of 0~60 days Jersey calves showed an increasing trend,and there was a difference in daily gain between the experimental group and the control group(P < 0.01),were increased by 16.7,33.3 and 80.0. ADG in test groups II and III was different from that in test group(P < 0.01).In conclusion:It is recommended that Jersey calves be fed colostrum to 6 days of age,which can reduce the diarrhea rate of calves,the treatment cost,and improve the survival rate and ADG of calves.

Key words: Jersey calf, ADG, IgG, diarrhea