Abstract: [Objective] To evaluate the application effect of probiotic preparations in the health management of dairy cows,this study took lactating cows from a large-scale dairy farm in Yishui County,Shandong Province,as the research subjects.A controlled trial method was used to systematically analyze the effects of probiotic preparations on the incidence of mastitis,milk quality,and milk production performance.[Method] Healthy lactating Holstein cows were randomly divided into a control group and a probiotic group.The control group was fed a basic diet,while the experimental group received the same diet supplemented with a compound probiotic preparation.The trial lasted for a continuous feeding period.By recording the incidence of mastitis and measuring milk quality indicators（somatic cell count,milk fat percentage,milk protein percentage,and lactose percentage） as well as milk production performance indicators （daily milk yield and milk production stability）,a comprehensive evaluation of the application effect of the probiotic preparation was conducted.[Result] The results showed that compared with the control group,the incidence of mastitis in the probiotic group was significantly reduced （P<0.05）,somatic cell count in milk decreased significantly （P<0.01）,and both milk fat and protein percentages increased to varying degrees （P<0.05）,while lactose percentage showed no significant difference （P>0.05）.The probiotic group showed a higher average daily milk yield than that of the control group,though the difference was not significant （P>0.05）,and exhibited better production stability;however,milk production stability was significantly better than that of the control group.Additionally,the probiotic group exhibited a lower incidence of subclinical mastitis compared to the control group,with a corresponding decrease in the average subclinical mastitis score,suggesting a reduced risk of subclinical mastitis.Regarding milk conductivity,the probiotic group demonstrated lower conductivity levels than the control group,indicating that probiotic preparations can alleviate the inflammatory burden on mammary glands and improve overall mammary gland health.[Conclusion] In conclusion,probiotic preparations can reduce the risk of mastitis by improving dairy cow health and reducing mammary gland inflammation,enhance milk quality,and increase lactation stability,demonstrating good potential for practical application and promotion.

Key words: probiotic preparation, dairy cow, mastitis, somatic cell count, application evaluation