Soil Nutrients, Bacterial Communities, and Veterinary Pharmaceuticals In Beef Cattle Backgrounding Confinement On Karst Environment.

In United States, beef cattle backgrounding represent an intermediate tier between the cow-calf enterprises and the feedlot finishing production.  Beef cattle backgrounding operations receive weaned calves from cow- calf enterprises and result in feedlot-ready yearlings. Beef cattle backgrounding, that adopt feedlot systems often congregate animals, feeds, manure and other livestock waste on small land areas. Hence, these sites may contain excessive soil nutrients, environmentally significant microbial communities and excreted veterinary pharmaceuticals that can pose adverse environmental impacts, especially related to the soil, water, and air quality. Better understanding on presence and distribution of such contaminants in cattle backgrounding sites would helpful in instituting effective BMPs and controlling potential environmental impacts. Field scale soil nutrients (N, P, Fe, Cu, Zn, and Na), microbial communities (amoA, narG) and veterinary pharmaceutical concentrations (monensin, lasalocid, and doramectin) distribution along transect from feeder to retention basin and to offsite sinkhole area were studied through surface soil sample analysis. Initial data showed that higher soil nutrient and veterinary pharmaceutical concentrations remained in the feeder area and varying amounts moved to retention basin area and even to the offsite sinkhole area. The proportions of narG and amoA bacteria were highest respectively in the feeder and sinkhole areas.