To help reduce excessive nitrates from manure, Penn State research is focused on reducing manure nitrogen by 30-50% and phosphorus by 40-60% by precision feeding dairy cattle. 

The Chesapeake Bay Commission has determined that, by far, the most cost-effective way to minimize the environmental impact of the large volumes of manure generated within the estuary’s watershed is by adjusting feed formulation for poultry and livestock, says Virginia Ishler, nutrient-management extension specialist in the College of Agricultural Sciences.

“Until recently, the focus has been on dealing with manure and its nutrients post-excretion,” she said. “However, now we are focusing on research and on nutrition programs to better balance nitrogen and phosphorus being fed to dairy cows. The feeding management — or how the ration is implemented and presented to the cows — can greatly affect nutrient levels and utilization. But that is just one component.”

The other component of the new enlightened management approach, Ishler explained, is utilizing as much home-grown feed as possible, especially forages, to minimize nutrients being imported onto a farm.

With funding from the National Fish and Wildlife Foundation, Ishler and research assistant Erica Cowan also are collaborating with the University of Maryland on a project in the Monocacy Creek watershed. In the Pennsylvania portion of the watershed, in Adams County, a Penn State team is monitoring dairy farms to determine the correlation between precision feeding and financial health.

“Every three months, ration information is collected, and total mixed ration and feed/forage samples are analyzed,” said Ishler. “We are also testing milk and monitoring urea nitrogen. Reports are sent back to the producer and their nutritionist after every sampling period to show where the herd is in relation to nitrogen and phosphorus goals.”

In southwestern Pennsylvania, Ishler and Indiana County extension educator Eugene Schurman are working with 12 dairy producers and their nutritionists, collecting nutrition and feed-management information every other month. This project is funded by the Northeast Sustainable Agriculture Research and Education program, a USDA competitive grants program supporting agriculture that is profitable, environmentally sound and good for communities.