| Brucellosis is a serious comorbidity of human and animal diseases.It mainly invades the reproductive system and lymphatic system after infection.The infection of female animals can lead to miscarriage and stillbirth.After infection of male animals,the testes and epididymis can be inflamed.Brucella can seriously damage the body's function.As it has not yet discovered a specific drug for treating the disease,it will eventually develop into a chronic disease.The disease is widely distributed worldwide,and effective control measures for the disease will pose a serious threat to animal husbandry and human health.Objective: To investigate the epidemiology of Brucella in large-scale dairy farms in a certain area of Shihezi City,prevent and control and gradually purify brucellosis in the area,and improve the economic benefits of dairy farming enterprises in the region.Methods: A total of 987 Holstein cows from three large-scale dairy farms in a district of Shihezi in 2014 were selected,including young cattle,bred cattle and lactating cows.Serum was collected.The Brucella serological investigation was carried out on the dairy farm by the combination of the tiger red plate agglutination test and the tube agglutination test.In order to compare the detection levels of different methods,the Brucella strains initially selected by the tiger red plate agglutination test were randomly selected.50 suspected positive serums were tested by tube agglutination test,immunocolloidal gold detection technology and fluorescence polarization detection technology;The positive serum was isolated and identified,and the bacterial morphology was identified by Kozlowski staining,The IS711 gene of Brucella was amplified by PCR and the bacteria were identified;scientific breeding management schemes were implemented for three large-scale dairy farms and different purification schemes were implemented.The changes in brucellosis infection between the three dairy farms between 2015 and 2017 were then monitored and the effects of the two regimens were compared.Results: In 2014,serological survey results showed that a total of 64 Brucella-positive sera were detected in 987 serum samples with a positive rate of 6.48%.The positive rate of Brucella in the serum of three cattle farms was 8.36%(29/347)in A cattle farm,6.53%(23/352)in B cattle farm,and 4.17% in C cattle farm(12/288);and the probability of infection of Brucella in dairy cows of different ages is different,among which the infection rate of lactating cows is the highest,the seroprevalence rate is 8.20%(35/427),the infection rate of young cattle is at the intermediate level,and the seroprevalence rate is 5.92%(19/321),the lowest infection rate of bred cattle was 4.18%(10/239);the seroprevalence of Brucella detection by different methods was also different,and the positive rate of fluorescence polarization detection technology was 100.00%(50/50),the positive rate of immunocolloidal gold detection technology detection is 94.00%(47/50),and the positive rate of test tube agglutination test is 84.00%(42/50);The serum of cows with positive serological test was cultured,showing pale yellow and translucent small colonies in solid medium and Kozlowski staining for Brevibacterium red,the results of the PCR test showed that 64 positive sera were infected with Brucella melitensis;after strict implementation of scientific management and prevention and control purification schemes in each cattle farm,3 The infection rate of Brucella in dairy cows in dairy farms showed a trend of decreasing year by year.Between 2014 and 2017,the seroprevalence of Brucella in dairy cattle in A cattle farm was 8.36%(29/347),7.55%(24/318),5.44%(16/294),and 3.96%(11/278);the seroprevalence of Brucella in B cattle farms was 6.53%(23/352),6.08%(20/329),5.18%(16/309),3.41%(10/293);the seroprevalence of Brucella in cows at C cattle farms was 4.17%(12/288),3.65%(10/274),and 2.27%(6/264),1.16%(3/258).Conclusion: In the method of serological detection of Brucella,especially the fluorescence positive detection technology has the highest detection rate and the most reliable test results;the dairy cows in large-scale dairy farms in a certain area of Shihezi are generally infected with Brucella melitensis.Dairy cattle breeding should adhere to scientific feeding management,regular immunization of healthy cattle,timely elimination of positive cattle,and no one is allowed to graze around the farm.This is very important for the prevention and control of brucellosis in cattle farms. |
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