Isolation And Identification Of Pathogenic Bacteria And Investigation Of Cow Subclinical Mastitis In Langfang

In recent years,the dairy industry is developing fast in our country,and has become a most complete industrial chain in the present agriculture.The dairy cattle feeding industry is one of pillar industries for increasing peasants' income and developing graziery.This study chose dairy cows from 10 different scales cattle farms(household)in different scale to carry on thes sample investigation in Langfang zone,researching disease percentage subclinical mastitis and isolation and identification pathogenic bacteria and medicine sensitive experiment in vitro,also discussing cow subclinical mastitis occurrence rule,the main pathogenic bacteria's type and the suppression effect of antibiotic.The study extracted a certain herd(1500cows)of different milk stages at random from Langfang zone for the experimental cow groups,carrying on the examination of the cow subclinical mastitis.As the investigation showed,the cow infection rate of subclinical mastitis was 41.2.%(618 of 1500).The examinations result alsos indicated that the cow subclinical mastitis may occur in any age,such as birth and milk stage,but become more serious with cow growth and miking time.Aslo the suffering cow's date milk yields was lower,indicating that the occurrence of cow mastitis could cause the date milk yield to drop the date milk yield greatly.The bacteria causing bovine subclinical mastitis were isolated and identified.The leading pathogens of subclinical mastitis were Staphylococcus aureus,Streptococcus and Escherichia coli.One hundred and ten bacterial strains were isolated from 67 milk samples of subclinical mastitis,including Staphylococcus aureus(46 of 110,41.81%),which was much higher than any other pathogens,Streptococcus(28of110,25.45%),Escherichia coli(17of 110,15.45%)and other pathogenic bacteria(19of110,17.27%).The result indicated that the infection whichs caused by only one kind of pathogenic bacteria were alones few,and most subclinical mastitis were the mixed infection whichs caused above 2 kinds of pathogenic bacteria.The researchs of drug sensitivity test was operated in vitro,showing that Gentamicin,Amikacin,CefalomicinaV and Norvancomycin had good inhibitory effect on Staphylococcus aureus.Streptococcus was highly sensitive to Benzylpenicillin,Streptomycin,Amikacin and Norvancomycin.Streptomycin,Amikacin and Enrofloxacin had good inhibitory effect on Escherichia coli.Staphylococcus aureus and Escherichia coli had very low sensitivity to Benzylpenicillin and ampicillin.The result of medicine sensitive experiment may be applied to clinical administration effcetively to prevent and treat subclinical mastitis in Langfang area,prevents and treats the occurrence of subclinical mastitis the Langfang area.