Effects Of Feeding Acidified Milk On Growth Performance, Blood Immunologic Indicator And Fecal Microorganism Diversity In Holstein Calves

The study was conducted to research the effects of feeding acidified milk on growth performance,blood immunologic function,and fecal microorganism diversity of calves in large scale dairy farm,and explored the effects of feeding acidified milk for calves.This paper was aimed at providing a theoretical support for making better use of acidified milk in large scale dairy farm.?1?Comparison of Nutrient Composition,p H Value and Microorganism Quantity Between Pasteurized Milk and Acidified MilkThe experiment compared the changes of milk composition,p H value and microorganism number between formic acid acidified milk and pasteurized milk.The results showed that pasteurized milk and acidified milk had no significant difference in nutrient composition,but the content of urea nitrogen in acidified milk was significantly higher than that in pasteurized milk?P<0.01?,and the p H value of pasteurized milk was significantly lower than the acidified milk?P<0.01?.Compared with pasteurized milk,the acidified milk significantly reduced the number of Escherichia coli in milk?P<0.05?and more significantly reduced the total number of bacteria in milk?P<0.01?.?2?Effects of Feeding Acidified Milk on the Growth Performance in CalvesThe experiment was designed with a completely randomized trial.In the experiment,20 healthy Holstein calves in the age of 3 days which had similar body height and weight,were divided into 2 groups randomly,each group with 5 repetitions and each repetitions with 2 calves.The feeding acidified milk was named AM group,and the PM group was fed with pasteurized milk.The experimental period was 180 days,and the suckling period was 60 days.The intake of liquid feed and solid feed was recorded,and body measurements and body weights were measured.Meanwhile,the daily weight gain and body measurement index were calculated.The feces score were performed daily and the calves diarrhea rate were calculated.The results showed that when the calves were at age 31-40 days and 41-50 days,the intake of liquid feed in the AM group were significantly higher than that in PM group?P<0.01?.At the time of 61-90 days,the intake of solid feed in AM group was significantly higher than that in the PM group?P<0.01?.When calves were at the age of 60 days and 180 days,the body weight of calves in AM group were significantly higher than that of PM group?P<0.01?;when calves were at the age of 90 days,the body weight of calves in AM group were significantly higher than that of PM group?P<0.05?;When calves were at the period of 31-60 days,61-180 days and 7-180 days the daily gain of AM group was significantly higher than that of PM group?P<0.05?.When thecalves were 7 days,the difference of body measurement index were no significant.When the calves were 30 days,the leg circumference and legs confining index of AM group were significantly higher than PM group?P<0.05?,chest deep of AM group was significantly higher than that of PM group?P<0.01?,limb length index of AM group was significantly lower than PM group?P<0.01?;When the calves were 60 days,body height and bone circumference of AM group were significantly higher than those of PM group?P<0.05?,and body length,chest circumference and chest depth were significantly higher than those of PM group?P<0.01?,limb length index and leg circumference index were significantly lower than those of PM group?P<0.01?;When the calves were 90 days,the bone circumference of AM group were significantly higher than those of PM group?P<0.05?and the straight body length,long body length,body height,chest circumference,and chest depth were significantly higher than those of PM group?P<0.01?.The leg circumference index of the AM group were significantly lower than those of the PM group?P<0.01?.When the calves were 180 days,the straight body length,long body length,chest circumference and chest depth of the AM group were significantly higher than those of the PM group?P<0.01?,the body length index were significantly higher than those of the PM group?P<0.05?,but the limb length index and body index were significantly lower than those of the PM group?P<0.05?.During each the period,the feces score and the diarrhea rate of AM group were significantly lower than those of PM group?P<0.05?.?3?Effects of Feeding Acidified Milk on Blood Immune Indices in CalvesCalves' blood were collected in the morning at the period of 7,30,60,90 and 180 days,and then the blood routine index and blood immune index were measured.The results showed as follow: at the time of 30 days,the WBC,LYM and LYM% in AM group were significantly higher than the PM group?P<0.05?,the TNF-?,IL-1? and IL-6 in the PM group were significantly lower than that in the PM group?P<0.05?;At the time of 60 days,the content of WBC,LYM,LYM%,IL-1? and IL-6 in AM group were significantly lower than that in PM group?P<0.05?,the content of Ig A were significantly higher than that in PM group?P<0.05?;At the time of 90 days,LYM% and IL-1? of AM group were significantly lower than that of PM group?P<0.05?,the content of Ig G and Ig M were significantly higher than that in PM group?P<0.05?;At the time of 180 days,the content of Ig M in AM group were significantly higher than that in PM group?P<0.05?.?4?Effects of Feeding Acidified Milk on the Fecal Microbes Diversity in CalvesFive calves with similar body weights were selected from each group at the time of 50 days and 90 days,respectively.In order to amplify and sequence 16 S r DNA,about 20 g feces samples were removed by scraping the end of the calves.At 50 days,the calves fed the acidified milkwere named AB group,the calves fed the pasteurized milk were named PB group.At 90 days,the calves fed the acidified milk were named AP group,the calves fed the pasteurized milk were named PP group,respectively.The results show that a total of 1,227,017 Tags can be used for subsequent analysis.OTU cluster analysis by each group showed that the number of specific OTU in the feces of acidified milk calves were lower than that of pasteurized milk.The 4 groups with the highest amount of bacteria were Firmicutes,Bacteroidetes and Fusobacteria.The LEf Se?LDA Effect Size?analysis result showed that species with significant differences in the AB group compared with other groups were Bacteroidaceae,Bacteroidetes,Faecalibacterium,Ruminiclostrid₉,Alloprevotella,Lachnospiraceae_UCG₀04,Lachnospiraceae_UCG₀10,Bacill,Lactobacillales,Blautia,the most influential species were Bacteroidaceae and Bacteroidetes.In summary,acidification of formic acid milk has little effect on the composition of milk,which can inhibit the growth of harmful bacteria in milk and improve the palatability.And in ad libitum of the calves feeding mode,acidified milk can increase the intake,reduce the diarrhea rate,improve fecal score,contribute to the growth and development of calves than pasteurized milk.Comparing with feeding pasteurized milk,feeding acidified milk could also improve immunity and influence the balance of the intestinal flora of calves,but its regulation mechanism remains to be further studied.