Investigation On Epidemiology And Development Of Multiple PCR Detection Method And Treatment Of Chinese Herbal Compound For Recessive Mastitis Of Dairy Cows In Jilin City

Mastitis is a common and frequent disease in dairy cows,which lead to decline dairy production capacity and milk quality,increase the elimination rate and treatment costs,and result in huge economic losses.Recessive mastitis is ignored extremely because of the unconspicuous symptom.Traditional detection methods of mastitis pathogens are mainly based on morphological characteristics,which takes a long time.At present,PCR test is widely used in one or two pathogens detection of mastitis pathogens.There are many kinds of pathogenic bacteria in mastitis,so the clinical application of PCR test for single pathogenic bacteria is limited.Multiplex PCR is an efficient and time-saving method for detecting multiple marker genes in a given sample.Therefore,this study conducted a systematic epidemiological investigation on dairy cows in Jilin city,analyzed the incidence of dairy cow mastitis,and established a multiplex PCR diagnostic method for detecting recessive mastitis of dairy cows,then treated cows with Chinese medicine.This study aimed to explore the regularity of cow recessive mastitis in Jilin area,preventd and controled recessive mastitis scientifically and effectively,and reduce economic losses for cow breeding industry.A total of 5,826 dairy cows were investigated in Huadian City,Jilin city from January to December 2019.The main pathogenic bacteria types of recessive mastitis in dairy cows in Jilin city were isolated and identified from the aspects of region,parity,month,milk yield,breeding method,lactation stage,milking method and feeding management level.The results showed that the highest incidence of recessive mastitis was 60.32% in Huadian city and the lowest was 35.31% in Yongji County.The incidence of recessive mastitis was the lowest at 2 parity was,and the highest at 7parity or above.The incidence of recessive mastitis was significantly increased from May to October and December and higher when annual milk yield was greater than7,000 kg.The incidence of recessive mastitis in free-ranging were higher than concentrated breeding and significantly increased during the peak and middle stage of lactation.The incidence of recessive mastitis was higher using hand milking than machine milking,and higher in bad feeding management level than that in excellent.The main pathogenic bacteria of recessive mastitis in dairy cattle in Jilin area are staphylococcus,escherichia coli and streptococcus agalactiae,and the mixed infection rate is higher.Therefore,prevention and treatment of mastitis were guaranteed by strengthening feeding management,scientific immunization,optimizing population structure,standardizing timely diagnosis and treatment,and rational utilization of cow production performance.In order to detect the staphylococcus,escherichia coli and streptococcus agalactiae and cross-infection of three pathogens in dairy cows with recessive mastitis,this study designed three different specific primers,adjusted and optimized of amplification reaction parameters by PCR amplification sensitivity and specificity experiments,established a multiple PCR amplification detection system.Results showed that the annealing temperature was 58? and the primer volume was 1 ?L,three bands of staphylococcus,escherichia coli and streptococcus agalactiae could be amplified simultaneously by MPCR from the mixed genome templates.Furthermore,the minimum dilution of each PCR reaction was 10 times.In this study,530 milk samples of suspected recessive mastitis from four regions in Jilin were detected by the established MPCR system and biochemical detection assays.Compared with biochemical detection assays,MPCR assays had a higher detection rate of 85.09%than 62.08% using biochemical assays.The milk yield and dry matter intake of cows with recessive mastitis were significantly reduced.However,the somatic cell count was significantly increased.These results showed that the MPCR method established in this study could quickly identify the three main pathogens of dairy mastitis,which was of great significance to the clinical detection of dairy recessive mastitis.In this study,Chinese herbal compound(hibiscus leaf,honeysuckle,forsythia,dandelion,loofah,Tong Cao,Fritillaria thunbergii)were used to treat cow mastitis.The rapeutic effect of Chinese medicine and antibiotic on recessive mastitis were analyzed and compared on the clinical cure effect,SCC,and milk yield of dairy cows in Jilin city.It was found that after 7 days of treatment,the cure rate and milk yield of Chinese medicine were significantly increased,and SCC in milk was significantly decreased,which was similar to that of antibiotic group.It indicated that the Chinese herbal formula selected in this study has obvious therapeutic effect on recessive mastitis and is expected to be popularized in the future.In conclusion,the incidence of recessive mastitis in dairy cows was affected by region,parity,month milk yield,breeding method,lactation stage,milking method,feeding management level,and pathogenic bacteria.In this study,the establish of multiplex PCR system for recessive mastitis pathogens detection in dairy cows have high detection efficiency and accuracy,which can be applied to production practice of dairy cows,and cows with recessive mastitis can be treated with Chinese medicine compound effectively.