Prevalence of Escherichia coli O157 and Salmonella spp. in solid bovine manure in California using real-time quantitative PCR.

The occurrence of Escherichia coli O157 and Salmonella spp. in solid bovine manure was investigated through a multi-county survey in California. Solid bovine manure samples (n = 91) were collected from 13 dairy farms located in multiple counties in California between June 2016 and August 2017. To quantify pathogens, DNA was extracted from bacteria in manure samples. Afterwards, the prevalence and levels of E. coli O157 and Salmonella spp. in solid bovine manure were determined by real-time quantitative PCR (qPCR). The prevalence of E. coli O157 and Salmonella spp. in solid bovine manure was 15·4 and 6·6% respectively. Escherichia coli O157 and Salmonella spp. levels in positive samples ranged from 3·1 to 5·3 log CFU per g and from positive (the population was <3 log CFU per g) to 5·2 log CFU per g respectively. Surface samples of manure piles had higher prevalence and levels of E. coli O157 and Salmonella spp. than subsurface samples, while no seasonal effects on pathogen occurrence were observed. Our results indicated that solid bovine manure is a source of E. coli O157 and Salmonella spp. and the application of untreated manure as biological soil amendments may pose potential risks to public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings suggested that the presence of Escherichia coli O157 and Salmonella spp. in solid bovine manure may pose potential risks if untreated manure is applied as biological soil amendments. Considering the large-scale sampling used in this study, the observations provide a holistic assessment in terms of pathogen prevalence in solid bovine manure.

Decision Making Tools: BeefTracker mobile app for tracking and analysis of beef herd pasture use and location.

Beef Tracker is a web-based mapping platform that provides beef cattle ranchers a tool to demonstrate that cattle production fits within sustainable ecosystems and to provide regional data to update beef sustainability lifecycle analysis. After digitizing pastures, herd data (class and number of animals) are input on a mobile device in a graphical pasture interface, stored in the cloud, and linked via the web to a personal computer for inventory tracking and analysis. Pasture use calculated on an animal basis provides quantifiable data regarding carrying capacity and beef production. This data is sought by the National Beef Cattle Association to provide more accurate inputs for beef sustainability lifecycle analyses. This application is a useful way for large, complex ranching operations to have all employees remain informed as to cattle movements and ranch wide improvement projects. Better yet, as users make changes to their operation in BeefTracker, histories are automatically recorded and stored in the cloud. After initial testing by university range scientists and ranchers, we have enhanced the BeefTracker application to improve automation for increased ease of use. The following have been added: ability to access and edit the BeefTracker livestock inventory while disconnected from WiFi and cell service, ability to represent portions of a pasture in BeefTracker as irrigated and nonirrigated, and ability to report animal unit harvest (by pasture) calculated on an annual basis. This will provide quantifiable data regarding carrying capacity and subsequent beef production to provide more accurate data inputs for the beef sustainability lifecycle analysis, enhanced map synchronization, and improved security to allow a single individual to access multiple livestock operations without needing multiple user IDs and passwords.