Epidemiological Investigation Of Endometritis Bacteria In Dairy Cows Along The Development Of Yellow-green Dairy Industry In Henan Province And The Difference Of Bacterial Flora Before And After Oxytetracycline Treatment

Endometritis is the main disease of Holstein bovine which damage reproductive performance.The disease has high incidence in China,resulting in milk production falling,more days open,conception rate decline per artificial insemination,risk of pregnancyincreased,repeatedly with infertility that eliminated.It seriously affected the Holstein bovine production and economic benefits.The occurrence of the disease mainly related with pathogen infection,breeding management,mating technology,environment,nutrition,hormone level and other factors.Researches showed that the pathogenic bacteria were the main cause of Holstein bovine endometritis.In clinical,endometritis was commonly treated with antibiotics,hormones and Chinese herbal medicine drugs by eliminating or inhibitting uterine infection.However,the deep mechanism of drug therapy is unclear,it has great scientific significance to elucidate the mechanism of drug treatment of endometritis on pathogenic bacteria.With the development of biotechnology,high-throughput sequencing technology has been widely used in veterinary for its high flux,read long,short sequencing time shorter,the low cost of sequencing.Therefore,this study investigated the epidemiological of five counties' Holstein bovine endometritis along the Yellow River basin in Henan province,and separated and identifd the pathogen,then discussed the effect of different levels of oxytetracycline treatment on endometritis in vivo and evaluated effect of oxytetracycline on microflora structure by using high-throughput sequencing technology.This study is mainly divided into three parts.Part 1: Epidemiology of Holstein bovine endometritis.The epidemiology of endometritis was investigated at Xinxiang Yuanyang,Jiyuan,Kaifeng,Zhengzhou Zhongmou,Luoyang Yanshi 5 counties along the Yellow River.The research involved 2656 adult dairy cows.The average incidence of Holstein bovine endometritis was 12.8%,which had differences between counties.The highest incidence was at July(14.7%)and August(15.3%)and lower incidence from March to June(ranged from 9.6% to 11.2%).The endometritis incidence of Holstein bovine endometritis rised with parity at investigated regions.Part 2: Isolation and identification of pathogenic bacteria in cow endometritis and clinical efficacy of oxytetracycline.Kaifeng and Yuanyang countries were selected for sampling to separate and identify pathogens because of their higher incidence of endometritis.The study found that single and mixed infection of endometritis existing at the same time in experimental farms,and mixed infection was higher than single infection.The main pathogenic bacteria of endometritis in Kaifeng Holstein farms were Escherichia coli and Staphylococcus aureus.The main pathogenic bacteria in Yuanyang country were Escherichia coli and staphylococcus haemolyticus.Forty Holstein endometritis cows were selected at Kaifeng farms,which were randomly divided into four groups,each group was treated with oxytetracycline at concentration of 0%,10%,15% and 20% respectively?Results showed that treatment with 20 ml 20% oxytetracycline solution treatment at once every other 2 days after four times has relatively higher effect?Part 3: Effect of oxytetracycline on the structure of bacterial flora in uterus of endometritis.The vaginal discharge of 27 Holstein bovine from Zhongmu county with endometriosis was evaluated by high-throughput sequencing.They were divided into Health group,Bacterium Carrier group,Infected group and Oxytetracycline treatment group.The sequencing and analyzing were completed through Illumina HiSeq 2500 Sequencing platform and related equipment as well as software.That total of 16 phylums,31 classes,55 Orders,97 families and 212 genera were identified?The Firmicutes is the dominant fungus both to endometritis and healthy dairy cows.After oxytetracycline treatment,Fusobacteria phylum and Bacteroidetes phylum decreased by 5.4% and 7.2%,respectively,which showed that the occurrence of endometritis was first based on the destruction of the flora dynamic balance.The result indicated that the number of them may be the key to the recovery of the uterus.The increasing percent of Bacteroides in clinical disease status indicated that the genus may be the main reason for the disease.