| Northeast China is an important region for dairy farming which plays a vital role in the industrial layout of Chinese dairy.However,with the promotion of modern intensive farming techniques,the incidence of nutritional metabolic diseases such as ketosis has remained high,representing a key issue that affects the production efficiency of dairy farms and severely restricts the healthy development of the Northeastern dairy industry.Therefore,it is necessary to conduct an epidemiological investigation of ketosis in dairy cows and propose effective prevention and control measures.Furthermore,commercially available ketone body test strips have disadvantages such as high prices and inability to perform batch operations,whereas the relatively inexpensive and easy-to-use ketone powder method can be optimized to become a useful tool for veterinary clinical screening and diagnosis of ketosis in dairy cows.In this study,a relatively systematic epidemiological investigation of ketosis in dairy cows was conducted at 56 large-scale farms across three provinces in the Northeast from January 2021 to December 2021.The relationship between regional factors,seasonal factors,dairy cow body condition score,parity,lactation stages,milk production,farm feeding management levels,and the incidence of ketosis was analyzed.The results showed that the average incidence of ketosis in the 56 farms surveyed was15.86%.Among them,in terms of regional factors,Heilongjiang Province had the highest incidence rate at 17.30%,while in terms of seasonal factors,the highest incidence rate occurred during winter,reaching 24.04%.Regarding body condition score,cows with a BCS>4.00 had the highest incidence rate of ketosis at 37.59%.With respect to parity,cows at their third lactation had the highest incidence rate of ketosis at 33.36%.In terms of lactation stages,the highest incidence rate of ketosis occurred during the first week after calving,reaching 27.72%.High-yielding cows had the highest incidence rate of ketosis among High-yielding cows had the highest incidence rate of ketosis among factors related to milk production,at 19.14%.Regarding farm feeding management,cows managed under poorer conditions had the highest incidence rate of ketosis at 37.61%.Therefore,it is essential to improve feeding management and strengthen daily monitoring of key herds to detect ketosis in a timely manner and implement appropriate diagnostic and therapeutic measures to reduce unnecessary economic losses on farms.In addition,the ketone powder method for detecting ketosis in dairy cows was optimized in this study,and a rapid screening kit for ketosis in dairy cows was developed with a conformity rate of 93.54%,sensitivity of 71.74%,and specificity of96.94%.The accuracy of the results obtained using the rapid screening kit was higher than that of the ketone powder method,with an improvement of 2.35% in conformity rate,10.87% in sensitivity,and 1.01% in specificity.In conclusion,the region,season,physical condition score,fetal,lactation phase,milk production and breeding management level in dairy cows for large-scale pasture in Northeast China have affected the incidence of ketosis.Key monitoring of high-risk dairy cows should be strengthened clinically.Rapid diagnosis of ketosis using the screening kit developed in this study supports for the detection of ketosis in small and medium-sized ranch,and large-scale screening can be used for large-scale custody ketosis used for large-scale ranchassist in timely detection and treatment of ketosis.It also can reduce the clinical missed detection rate of ketosis in dairy cows and minimize economic losses on farms. |
