Download or read book The Role of Cattle Grazing Management Practices and Environmental Factors in the Spread of Waterborne Pathogens in California Sierra Nevada Meadows written by Anyarat Thiptara and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Water-related diseases remain a leading cause of morbidity and mortality, particularly affecting children in developing countries. The U.S. Environmental Protection Agency (U.S. EPA) has been using fecal indicator bacteria (FIB) to inform regulation of water quality across the nation. Cattle serve as a natural reservoir of waterborne pathogens; hence, cattle grazing in mountain meadows may play role in waterborne pathogen contamination and increasing risk of related recreational diseases. In this dissertation, the analyses focuses on three areas: 1) to clarify the link between waterborne pathogens and cattle grazing practices in California's Sierra Nevada; 2) to estimate cattle fecal loads in riparian areas and to better understand the role of grazing management and spatial factors in fecal deposition in California's Sierra Nevada; 3) to evaluate the association between upstream and downstream FIB concentrations, while accounting for grazing management, resource use activities and spatial factors, and to better understand the transport and fate of FIB as surrogates for waterborne pathogens. Chapter 2. In this cross-sectional study, range cattle feces and creek water samples around Lake Davis in Plumas County were collected to detect Salmonella, E. coli O157H:7, Cryptosporidium, Giardia and fecal indicator bacteria in the summer of 2011. Neither Salmonella nor E. coli O157H:7 were found in fecal and water samples. Cryptosporidium and Giardia loads (adjusted for percent recovery) in meadow creek water ranged from 0-2.8 oocysts/l and 0-2.3 cysts/l, respectively. Waterborne protozoa were found in both grazing and non-grazing areas, suggesting non-bovine sources exist in this watershed. Sequence analyses confirmed C. parvum and possible mixed concentrations of G. intestinalis assemblages B and C. Based on these water volume concentrations, ingestion of 3.6-9.1 and 4.3-14.3 l of creek water yielded a 50% infection probability, assuming that all (oo)cysts are pathogenic and infectious. Overall prevalence of Giardia and Cryptosporidium in range cattle at this site was 19.5% (8/41) and 2.4% (1/41), respectively. Calves had 4.3 times higher risk of yielding a positive test result for Giardia than were adults (95% CI: 1.31-14.21; P = 0.04). Genotyping of positive feces revealed C. andersoni and G. intestinalis assemblage E. Because Cryptosporidium and Giardia found in creek water and cattle feces were different assemblages, the source of protozoa was unlikely to be cattle, and no association was found between fresh bovine fecal loads and concentration of waterborne protozoa. Chapter 3. Disproportionately high livestock grazing in riparian areas is a critical rangeland watershed issue across the U.S., as it affects the conditions of riparian ecosystems. We conducted a cross-sectional study with over 160 transects in riparian areas across the Sierra Nevada meadows of California to investigate various factors that led to high fecal deposition in the summer of 2012. Using a mixed-effects linear regression model, factors associated with wet fecal loads (g/m2) included grass coverage in transect (%), length of cattle trail (m), pasture adjacent to transect (km2), and stocking density in adjacent pasture (cow-calf pairs/km2). With all factors held at median values, the estimated mean cattle fecal load was 121.75 g/m2. During summer cattle spent their time close to streams and heavily used riparian areas more than uplands because of environmental and nutritional factors. Transects with a high percentage of grass coverage were attractive to cattle, so they spent time grazing and defecated more in these areas. The transects with small adjacent pastures were likely to be grazed and visited. Fecal deposition in transects declined when pastures adjacent to transects were substantially larger, and increased when the length of cattle trails within the transects increased. Stocking density in adjacent pastures had the weakest influence on the fecal loads. The changes in fecal loads were almost constant when the stocking density increased. These results suggest that grazing management strategies should be implemented in areas with narrow adjacent pastures, especially, the areas with high percentages of grass coverage and lengthy cattle trails. Chapter 4. In this study, we used data from a panel study conducted on U.S. Forest Services-managed public lands in northern California between May 25, 2011 and November 1, 2011. Water samples at each site were analyzed monthly for two FIB: fecal coliforms (FC) and E. coli (EC). Seventy-two upstream-downstream sampling site pairs were generated, and 330 water-pair samples were included in this study. FIB median downstream concentrations were highest between September and October, coincident with when cattle reached their highest stocking densities. Both descriptive and multivariate analyses demonstrated that sites with cattle present had significantly higher FIB downstream concentrations than sites without cattle. FIB downstream concentrations also were significantly positively correlated with FIB upstream concentrations and water turbidity. Only FC downstream concentrations significantly differed by upstream-downstream distance quartiles, and rain events had a significantly negative correlation with FC downstream concentrations in multivariate analyses.