Effects Of Compound Plant Extracts On The Health And Growth Of Suckling Calves

The establishment of immune function,digestion and metabolism,rumen development and microbial flora of calves have an important impact on the health of adult calves.The experiment was conducted to study the effects of compound plant extract feed additive on growth performance,blood biochemical indexes and diarrhea rate of calves aged 7-21 days and 53-60 days respectively,so as to provide theoretical basis for the application of Chinese herbal extracts in ruminant production.Healthy Holstein calves with the same parity and similar body weight(40.2±1.3kg)were randomly divided into three groups: group 0,group I and group II,each calf was added 1g and 2g compound plant extract feed additive in daily drinking milk.The diarrhea index,blood biochemical indexes and growth performance of calves were measured at 7,14 and 21 days of age.The results showed that:Diarrhea index: the 0-point normal fecal index of calves in group II was 50.83%higher than that in group I and 83.61% higher than that in group 0;there was no significant difference among groups with 1 point of mild soft stool;the diarrhea index of group II increased by 75.63% and 78.75% respectively compared with group 0 and group I in 2 points of moderate feces;the diarrhea index of calves in group II with 3severe feces was the lowest.Microbial diversity: Chao1 and ACE index of the control group were significantly higher than those of the control group(P<0.05).There was no significant difference in Shannon index and Simpson index(P>0.05).Blood biochemical indexes: the content of IgA in serum of calves in each group was at the highest stage at 7 days old,and showed a downward trend at 21 days old,but there was no significant difference among the groups(P>0.05);the range of decrease was the largest in group 0,which increased by 5 mg / ml at 21 days old and11.64 mg / ml at 14 days old in group II at 21 days old.There was no significant difference in serum IgG content between groups at 7 days of age(P>0.05);at 14 days old,the serum IgG content of group I increased significantly compared with the other two groups(P<0.05);there was no significant difference between group 0 and group II(P>0.05),but the IgG content of group II showed an increasing trend with the increase of age.The initial IgM content in serum of group 0 was the highest,and there was significant difference between group 0 and groups I and II at 7 and 14 days of age(P<0.05),but there was no significant difference between groups at 21 days old(P>0.05).There was no significant difference in the content of IL-β between 7 and 21 day old groups(P>0.05).The content of TNF-α in group 0 was significantly higher than that in group I and group II at 7 days of age(P<0.05),but there was no significant difference between groups at 14 days old and 21 days old(P>0.05).Growth performance: there was no significant difference in the initial body height,chest circumference and body slant length among the groups(P>0.05).At 14 and 21 days of age,the body height of group II and group I was significantly higher than that of group 0(P<0.05).There was no significant difference in chest circumference and body length between groups at 14 and 21 days of age(P>0.05).The addition of compound extract feed additive in normal milk had little effect on the growth rate of body size of calves at 7-21 days old.Calves were weaned at 60 days of age.In order to alleviate the adverse reactions caused by weaning stress,the compound plant extract feed additive was added to the calves at 53 days of age.The feeding method was the same as that in the first stage of the experiment.The feeding amount was as follows: the control group 0 was not added,and the experimental group I and group II were supplemented with 2.5g and 5g compound Chinese herbal medicine respectively in daily drinking milk Agent.The results show that:Blood biochemical indexes: the immune results of weaning calves(60 days old)showed that there was no significant difference in IgA content among the groups(P>0.05),but there was an upward trend with the increase of feeding dose.The contents of IgG and IgM in group II were significantly higher than those in group 0 and group I,and there was no significant difference between group 0 and group I(P>0.05).The contents of IL-β and TNF-α in group I were significantly higher than those in other two groups(P<0.05),but there was no significant difference between group 0 and group II(P>0.05).Anti stress: the serum total antioxidant capacity(T-AOC)of 60 day old weaned calves in group II was significantly higher than that in group 0 and group I(P<0.05).There was no significant difference in SOD content among groups(P>0.05).Growth performance: the height and slant length of calves in group Ⅱ were significantly higher than those in group 0 and group Ⅰ(P<0.05).The chest circumference of calves in group II and group I was significantly higher than that in group 0(P<0.05).There was no significant difference in the birth weight among the groups(P>0.05),but with the increase of the dosage of plant extract feed additive,the intermittent milk weight,daily gain during lactation and growth index of calves in group II were significantly higher than those in group 0 and group I(P<0.05).The above results showed that the compound extract feed additive could promote the growth performance of calves.Although there was no significant difference in the early lactation(7-14 days old),the growth promotion effect was significant in the weaning period(53-60 days).Moreover,the content of IL-β in the blood of experimental group was lower than that of the control group,which could improve the health of calves.It can prevent calf diarrhea and inhibit the proliferation of intestinal harmful bacteria.The results showed that feeding compound extract feed additive before weaning did not affect the normal growth and development of calves.The body weight and body size of calves in the experimental group at 60 days of age were better than those of normal lactation calves;and the calves fed with 5g additive had better anti stress ability.It is suggested that the two-stage feeding,2 g / head / d for 7-21 days old and 5 g/ head / d for 53-60 days old can obtain good growth promotion effect.