| Dairy cow mastitis is a major disease with high incidence,complexity and difficulty in prevention and control in large-scale pastures.Its comprehensive prevention and control cost is high,which will not only increase the elimination rate of dairy cows and affect the economic benefits of pastures,but also affect the quality of milk and food safety.Xinjiang winter cold(minimum of-35 ?),the summer heat(up to + 35 ?),hot cold stress is large,the pathogenesis of mastitis and pathogen is relatively complex,with higher percentage of staphylococcus aureus mastitis,mastitis in order to check this area because the hair cause of disease and the status quo of staphylococcus aureus infection,a set of scientific and reasonable comprehensive prevention and control measures are put forward,this study intends to carry out the following several aspects:Firstly,9 large-scale pastures in shihezi,changji,shawan and kuitun were selected as the research objects.The causes and current situation of mastitis were evaluated by means of field epidemiological investigation and ranch management software query.Secondly,milk samples were collected aseptically,and staphylococcus aureus was isolated and identified by the combination of conventional microbiology and PCR.Meanwhile,its drug-resistant phenotype and genotype were analyzed.Finally,a scientific and reasonable comprehensive prevention and control plan for staphylococcus aureus mastitis was proposed according to the results of drug sensitivity test,the current situation of clinical drug use and the experimental results of different drug comparison treatments.The results are as follows:1.During the period from January 2019 to December 2019,the field epidemiological investigation of 1,200 cows in nine large-scale pastures in shihezi and other regions and the tracking query results of pasture management software showed that:The average incidence of recessive mastitis was 42.35%.The incidence of recessive mastitis in dairy cows was significantly associated with the lactation stage,and the incidence in the late lactation stage was higher than that in the early lactation stage.As cows age,the risk of infection increases;The incidence in the posterior region was higher than that in the anterior region.There was a positive correlation between the number of births and the incidence rate,and the incidence rate of cows with more than three births increased significantly.2.Pathogen isolation and identification and drug resistance analysis results:The isolation rate of staphylococcus aureus in milk samples was 26.70%(216/812),and the drug-resistant phenotypes and genotypes of 105 isolates were basically the same.The drug resistance rates of ceftriaxone sodium,cefotaxime,kanamycin,azithromycin,ciprofloxacin,cefthiophene,doxycycline,benzacillin,erythromycin,amoxicillin,ampicillin and penicillin G were 13.3%,33.3%,46.67%,53.33%,60.00%,60.00%,60.00%,66.67%,80.00%,86.67%,93.33%,respectively.The carrying rates of the drug-resistant genes blaZ,norA,rpoB,adeB,sepA,tetK,smr-1 and aaca-aphd were 94.3%,95.2%,63.8%,56.2%,60.0%,65.7%,40.95% and 46.67%,respectively.The results showed that the drug resistance of the isolates was serious,and the rate of resistance to most antibiotics was more than 50%.3.44 Clinical treatment test results of staphylococcus aureus mastitis cows showed that the cure rate of Ruzhang(ceftaxime hydrochloride)was the highest 75%,and the cure rates of ceftriaxone sodium,ceftaxime,doxymycin and benzoxacillin were 62.5%,62.5%,50% and37.5%,respectively.In order to thoroughly from the source to eliminate the infection and spread of staphylococcus aureus,eliminate the onset of serious positive bull advice ranch,coupled with comprehensive prevention and control of the experimental results,the recessive mastitis,one by one to detect when dry milk at the same time adopt "milk + Abe chang ning +closed ning" method of staphylococcus aureus mastitis of comprehensive prevention and control. |
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