The Relationship Between Bacterial Changes In Bedding And Mastitis Of Dairy Cows

The rapid expansion of large-scale dairy industry has raised concerns about the pollution caused by cow manure and its treatment in the cowshed in China.The use of cow manure bedding has been proposed as a solution to handle large quantities of cow manure and effectively reduce the impact of fecal pollution on the environment,while also providing a comfortable lying environment for dairy cows.However,there are significant risks associated with using cow manure bedding,including the high risk of pathogen infection in cows and the potential breeding and spread of pathogenic bacteria due to fecal pollution and untimely replacement of the bedding,which can impact the health of dairy cows ultimately.Despite the importance of this issue,there is limited research available currently.Therefore,this study aims to examine changes in pathogenic bacteria in cow manure bedding during use and their relationship with mastitis in dairy cows.The study tested the count of bacteria of cow manure bedding in different locations of loose housing systems in the barn.The study also analyzed the homology between bacteria in the bedding and those causing mastitis.1.The total count of bacteria in the middle and back parts of the bedding was significantly higher than that in the front part(p<0.01).The number of Escherichia coli,Klebsiella pneumoniae,and Salmonella spp.in the back part of the bedding was significantly higher than that in the front and middle parts(p<0.05 or p<0.01).2.The environmental temperature and daily incidence of clinical mastitis were investigated,and the relationship between environmental temperature,incidence of clinical mastitis,and total bacterial count in the bedding was analyzed.The results showed that the environmental temperature in August was higher than that in April and November.The total count of bacteria in the cow manure bedding and the incidence of clinical mastitis in August were significantly higher than those in April and November(p<0.05).There was a highly significant correlation between barn temperature and total bacterial count in the back part of the bedding(r=0.596,p<0.05),and a significant correlation between total bacterial quantity in the back part of the bedding and incidence of clinical mastitis(r=0.678,p<0.05).These results indicate that the total number of bacteria in the back part of cow manure bedding and the incidence of clinical mastitis are related to the barn environment temperature.3.The total bacterial count of bedding decreased after new bedding was added,and then gradually increased and stabilized after 2～3 days.The total bacterial count in the back part of the bedding and on the surface of udders showed a synchronous increase or decrease,with a significant correlation between the two(r=0.685,p<0.05).4.Some strains of Escherichia coli and Klebsiella pneumoniae in the bedding and clinical mastitis belonged to the same clone group,and some strains had the same ST typing,indicating that Escherichia coli and Klebsiella pneumoniae in clinical mastitis were derived from cow manure bedding.