Oxytetracycline runoff showed up after every single rainfall event in a four season field trial, at 0.13 to 0.26 micrograms per milliliter. The setup was plain: 100 g deposits of fortified swine feces left on grass covered soil for 30 days per season, with passive collectors downslope taking the flow. Between 0.02 and 0.07 percent of the fortified mass left in water. All of it still ran 220 to 540 times above the concentration meant to keep resistance selection away. Why oxytetracycline runoff matters on swine operations Oxytetracycline came out of Streptomyces rimosus as a first generation tetracycline, and pigs still get plenty of it. Oral dosing is the default…