Cover crops feature prominently among agricultural Best Management Practices to improve water quality in the streams, lakes and estuaries of the northeastern U.S. The benefits of cover crops after corn silage are clear: they help protect the bare soil from soil and nutrient losses in runoff, and protect leaching of nutrients, especially important since manure is typically applied on these fields. Besides their environmental and soil improvement benefits cover crops can also be a valuable forage which makes their use much more attractive to dairy farmers. Cover crop mixtures are becoming a focus in our work because the different species can complement each other to meet farmer goals. We evaluated several cover crop mixtures on approximately 10 dairy farms from 2010-2013 in all agro-ecological regions of Pennsylvania. We present cover crop biomass production, N and P uptake, and forage value in this paper.