Epidemiological Investigation Of Parasitic Diseases In Dairy Cattle At Three Large-scale Dairy Farms

Milk and dairy products have long been an essential part of the Chinese dinner table,So dairy cattle breeding is an important part of livestock and poultry breeding in China.As the source of milk production,dairy farming needs to be both safe and efficient.Cow parasitic diseases are one group of the most important diseases hindering the rapid and safe development of dairy farming in modern China.Parasitic diseases in dairy cows can hinder the absorption of nutrients in digestive tract,cause nutrition problems in dairy cows,reduce feed conversion rate and the yield as well as quality of milk,retard the growth of calf and even cause the calf death.In addition,certain parasitic diseases threaten the health of farm workers.The prevalence of parasitic diseases in dairy cows is one of the problems to be solved in dairy cattle breeding industry.Before prevention and control,it is necessary to understand the specific epidemiological situation of dairy cow parasitic diseases in the pasture,so as to develop a targeted prevention and control program.In this study,microscopy and molecular biology methods were used to investigate the epidemiology of dairy cow parasitic diseases in three large-scale dairy farms.The three pastures are Qiaonuer Pasture in Yichang City,Hubei Province,Shandong Gaoshu Pasture in Jinan City,Shandong Province,and Yinxiang Weiye Pasture in Heze City.First,sample multiple ranches in different seasons,and then use Mc Master’s egg counting method and Liao’s count method to conduct a total of 509 dairy cow feces samples from three large-scale ranches for nematodes,flukes and tapeworms.Identification and counting of worm eggs and coccidian oocysts to obtain epidemiological data of common digestive parasitic diseases in dairy cows in these pastures.In this study,a total of 361 blood samples of dairy cows from large-scale pasture cows from three places were tested for protozoa by PCR method;the previous stool samples were tested for several common parasitic nematodes by PCR method.Through microscopic examination and counting of parasite eggs and oocysts in dairy cow feces samples from three large-scale pastures,the results are as follows: Before prevention and control,the dairy cow parasites in Qiaonuer Pasture in Yichang,Hubei were mainly nematodes and trematodes.The infection rate was 44.17% and 15.95%,a small amount of coccidia infection,the total infection rate was 9.82%,and no tapeworm was detected.The average number of total egg counts of nematodes,flukes and coccidia were 161.35/g,7.88/g and 26.38/g,respectively.There is a significant difference in the infection rate of nematodes in cows in Qiaonuer Pasture in spring and autumn and in winter.There is a significant difference in the infection rate of fluke in spring and autumn and winter,and the infection rate of coccidia in autumn and the other two seasons.After the use of ivermectin injection for dairy cows,after deworming and control,the nematode infection rate in Qiaonuer Pasture was reduced to 5%,and the number of nematode eggs was reduced to 10 /g.The prevention and control program was effective.Before prevention and control,the parasitic infections of dairy cows in Shandong Gaoshu Pasture and Yinxiang Weiye Pasture were mainly nematodes,with a small amount of coccidia infections,and no fluke and tapeworms were detected.The total infection rate of nematodes and coccidia in Shandong Gaoshu Pasture was 10% and 5% respectively,the total infection rate of Yinxiang Weiye Pasture was 11.11% and 2.96% respectively.The infection rates of nematodes and coccidia in the two pastures in the two seasons were not significantly different,and the infection rate was higher in summer.The average number of total egg counts of nematodes and coccidia from Shandong Gaoshu Pasture was 32.50/g and 17.50/g respectively;the average number of total egg counts of nematodes and coccidia from Yinxiang Weiye Pasture was 23.70/g respectively G and 8.89 /g.There were significant differences in the amount of nematode and coccidia infections in the two pastures and two seasons.The infection rates of nematodes and coccidia in the two pastures were higher in summer.After using the same prevention and control plan for prevention and control,the nematode infection rate in Yinxiang Weiye Pasture was reduced to 4.3%,and the nematode egg count was reduced to 4.4 /g.The prevention and control plan was effective;the nematode infection rate in Shandong Gaoshu Pasture was 22.2 %,the nematode egg count was 63.89/g,and the prevention and control program did not produce any effect.The PCR method was used to detect three common dairy cow parasitic nematodes.Ostertagia and teladorsagia circumcincta were detected in Qiaonuer Pasture with the infection rates of 5.41% and 0.9%,respectively.Teladorsagia circumcincta was also detected in Shandong Gaoshu Pasture with the infection rate of 5%.Ostertagia and teladorsagia circumcincta were detected in Yinxiang Weiye Pasture with the infection rates of 4.44% and 2.96%,respectively.Haemonchus contortus wasn’t detected in all three farms.The results of the examination of protozoa by PCR are as follows: Piroplasma was detected in all three farms,but no Neospora was detected,and Toxoplasma gondii was detected in Qiaoniuer and Yinxiang Weiye Pastures.The total infection rates of Piroplasma and Toxoplasma in Qiaoniuer Pasture were 26.67% and 15.56%,respectively.Theileria sergenti was a dominant species in the detected Piroplasma.There was no significant difference in the infection rates of the two protozoa between the two seasons.The total infection rate of Piroplasma in Shandong Gaoshu Pasture was 14.77%,and there was no significant difference in the infection rate between the two seasons.Theileria sergenti was a a dominant species in the detected piroplasma,and Toxoplasma gondii was not detected.The total infection rates of Piroplasma and Toxoplasma in Yinxiang Weiye Pasture were 18.03% and 2.73%,respectively.Theileria orientalis was a dominant species in the detected Piroplasma.There was a significant difference in the infection rate of Piroplasma between the two seasons,and the infection rate is higher in summer.There was no significant difference in the infection rate of Toxoplasma between the two seasons.There was no significant difference in the infection rate of Piroplasma in the three pastures;however,there was a significant difference in the infection rate of Toxoplasma gondii between the Qiaoniuer Pasture and the other two pastures.