Effects Of Compound Plant Extracts On Rumen Fermentation,Milk Production Performance And Bacterial Flora In Dairy Cows

The purpose of this thesis was to study the effects of compound extracts which include Dandelion,Leonurus Japonicus,Lonicera Japonica Thunb and Forsythia Suspensa on the rumen fermentation,milk performance and bacterial flora in lactating Holstein cows.This test was divided into two parts:in vitro fermentation test and feeding test.Firstly,the effects of compound plant extracts on rumen fermentation parameters in Holstein cows were studied under the conditions of rumen fermentation in vitro,and on this basis,the optimum dosage of compound plant extracts was selected.The effects of compound plant extracts on the milk performance and rumen bacterial flora in Holstein cows were studied by animal experiments.The specific process and main results of the test are as follows:The first experriment was to study the effects of compound plant extracts on rumen fermentation and screened the optimal dosage in Holstein dairy cows by using in vitro batch culture method and multipie factors associative effects index(MFAEI).The rumen fluid was collected from 4 healthy Holstein dairy cows with the same lactation period and similar body condition as the rumen fluid donor.The compound plant extract was made up of Dandelion,Leonurus Japonicus,Lonicera Japonica Thunb and Forsythia Suspensa by ethanol extraction and then mixed 1:1:1:1:1 by mass.Added 2.0 g air dried total mixed ration to artificial rumen culture bottle,used a completely randomized design and divided the subjects into one control group and three test groups.The control group used basic diet as fermentation substrate,and in the test group,0.03%,0.3%and 3.0%compound plant extracts were added to the fermentation substrate,respectively.Each group had six fermentation time points at 2 h,4 h,6 h,8 h,12 h and 24 h,and each fermentation time point had three repeats.The results showed that under the condition of in vitro culture,the addition of different dosages of compound plant extracts had no significant effect on rumen pH,the concentration of acetic acid and acetic/propionic acid ratio in dairy cows(P?0.05).In vitro fermentation toat 8 h,the concentration of NH3-N,total volatile fatty acids and propionic acid increased significantly(P?0.05).It has the effect of improving the dry matter degradation rate and gas production.In vitro fermentation at 4 h,the dry matter degradation rate of 0.03%and 0.3%two dose group are significantly higher than that of the control group(P?0.05),and in vitro fermentation at 6 h,gas production increased significantly(P?0.05).Compared with the control group,the concentration of MCP was reduced,and the in vitro fermentation at 2 h and 12 h showed a significant level(P?0.05).According to MFAEI,the addition of compound plant extracts could effectively regulate the rumen fermentation of dairy cows,and the optimal additive content of compound plant extracts in dairy cow was 0.3%.The second experiment was conducted to study the effect of compound plant extract on milk performance in dairy cows.We randomly divided ten Holstein cows with good health and similar body weight into two groups,each group had 5 cows.The composition of ration was the same as the second experiment.The test was conducted for a total of 60 days,of which the pre-feeding period was 15 days and the official period was 45 days.Daily milk yield was recorded throughout experiment.The composition of milk and the number of somatic cells in milk was measured at the 1st,15th,30th and 45th day of formal trial.The intake of dry matter was measured after 3 days of concentrated house feeding.The results showed that compared with the control group,the dry matter intake of dairy cows at the 15th,30th and 45th day groups decreased,but the difference was not significant(P?0.05),and the average daily milk yield of dairy cows at the 1st,15th and 45th day groups increased(P?0.05).At the 1st,15th and 45th day,the number of milk somatic cells decreased(P?0.05),and at the 30th day,the number of milk somatic cells was decreased significantly(P?0.05).And at the 1st,15th and 45th day,the percentage of milk fat was increased,but the difference was not significant(P?0.05),and for the milk protein rate,lactose rate,non-fat milk solid content and total solid content,the test group was higher than the control group at each time point,but the difference was not significant(P>0.05).The third experiment was conducted to study the effect of compound plant extracts on rumen bacterial flora in dairy cows.Twenty-four Holstein dairy cows were randomly divided into two groups,each group had 12 cows.The control group was fed with basal diet and the test group was fed with 0.3%compound plant extract per day of DM.The rumen fluid was collected on the 60th day of the trial.The total DNA of rumen fluid was extracted and 16s rRNA sequence analysis was used to study the changes of rumen bacteria in dairy cows.The results showed that the test group and the control group could separate each other at the OUT level.Compared with the control group,the Shannon Index,Simpson Index,ACE index and Zhaol Index of rumen bacteria in the test group had no significant difference.Community coverage was more than 99%,means that the sample collection could reflect the rumen bacteria.Compound plant extracts could change the relative abundance of 17 Phyla in the rumen in dairy cows,but the difference was not significant(P>0.05),and Bacteroidetes and Firmicutes were the most.The relative abundance of rumen Bacteria in the test group was not significantly different from that in the control group at genus level,and the dominant bacteria were Prevotella.Compared with the control group,the relative abundance of Bacteroidales in the test group was significantly lower,but the relative abundance of Bifidobacteriaceae was significantly higher by LEFse analysis.In conclusion,adding 0.3%compound plant extracts to the diet of dairy cows had no negative effect on rumen bacterial flora,and could enrich the bacterial diversity in rumen fluid.In conclusion,the compound plant extracts of Dandelion,Leonurus Japonicus,Lonicera Japonica Thunb and Forsythia Suspensa has the effect of optimizing the rumen fermentation in dairy cows.Adding 0.3%compound plant extracts to the diet could effectively improve the rumen bacterial flora.It has a tendency to increase the milk production and milk composition of dairy cows and reduce the number of somatic cells in milk,and it has anti-inflammatory potential.