This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.
Stainless steel’s all the rage in gourmet kitchen design, but its appeal could soon extend well beyond the kitchen to the nation’s dairy farms, thanks to intriguing discoveries by Agricultural Research Service (ARS) scientists at the agency’s Animal Waste Management Research Unit in Bowling Green, Ky.
The scientists say switching to stainless steel watering troughs could be an important step toward controlling Johne’s disease, which can cause losses of as much as $200,000 per year in a herd of 1,000 dairy cows. Those losses are mostly from reductions in milk production and the need to cull infected animals.
Johne’s disease is caused by the bacterium Mycobacterium paratuberculosis. The ARS scientists suspected that water troughs might provide a perfect home for bacteria, so they counted the Mycobacteria on the sides of the most commonly used troughs: concrete, plastic, stainless steel or galvanized steel.
While the scientists found high concentrations of the bacteria on all the troughs within three days of inoculating the water with the bacteria, and those bacteria survived for more than 149 days, the bacterial survival rate was lowest on the stainless steel.
The scientists say there’s a simple trick to making the troughs even less hospitable for the bacteria: add 3 tablespoons of chlorine bleach per 100 gallons of trough water weekly. When the scientists tried that, by the end of the third week, less than 1 percent of the bacteria still lingered in the stainless and galvanized steel troughs. That’s compared to 20 percent remaining in the plastic troughs and 34 percent in the concrete troughs.