The Investigation Of Major Pathogens Causing Calf Diarrhea And Their Control In Beijing

Calf diarrhea is the major cause for the death of calves. In this study,we investgated the epidemiology of calf diarrhea in the cattle farms in Beijing and its major pathogens. Data from cattle farms in Beijing showed that, the average rate of calf diarrhea was 18.80%, the average mortality rate was 2.45%. In detail,986 plasma samples and 3360 stool samples from 30 dairy farms in 8 major districts of Beijing were collected for pathogens detection. The results of continuous detection of pathogen were as follows:BVD average positive serum was up to 24.44%, rotavirus detection rate was 11.10%, coronavirus detection rate was 2.20%, Cryptosporidium was 7.23%, pathogenic E.coli was 5.71%; rotavirus and cryptosporidium was the most important case, taking up 35.00% of the mixed infection. Based on the epidemiology of calf diarrhea, we developed a systematic prevention and control program to assure the healthy development of the cattle industry.The survey on coccidiosis epidemiology showed that coccidia existed in all cattle farms.The average OPG was 549 and infection rate was 23.88% among the 2307 stool samples from 30 farms. Seven species of Eimeria were identified as follows:E. zuernii (33.01%), E. bovine (31.09%), E. ellipsoidalli (25.32%), E. canadensis (2.53%), E. subspherica (4.41%), E. cylindrce (1.34%), E. bukidnonensis (1.45%). Mixed infection of several species of Eimeria were very common in calves. E. zuernii was the main pathogenic species.The survey on the Giardia and Cryptosporidium epidemiological showed that 14 of 822 dairy cattle fecal samples were giardia positive (1.09%),. The calves from 0 to 6 months had the highest infection rate. It has been identified as genotype E by PCRand the Beijing isolates was most similar to the Giardia isolated from the nearest Henan Province based on the sequence polymorphism analysis, indicating that there is no regional isolation of Giardia infection. Cryptosporidium infection rate was 2.55%, three species were found, e.g. C. andersoni and C. parvum, C. parvumas. C. parvum IIdA15G1 genetic subtypes that infects both humans and animals was the dominant species,.Comprehensiving the epidemiological and etiological analysis, and the principle of animals’ diseases control, we established comprehensive prevention strategy to control calf diarrhea. The strategy was based on bioremediation and healthy farming practices and supported by rapidly diagnostic methods and emergency treatment. Following our strategys, gratifying results were achieved,, the incidence of calf diarrhea in the region was decreased from 20.85% to 16.82%, and the mortality rate had decreased from 2.90% to 1.85% over the past three years.