The National Research Council's "Nutrient Requirements For Horses" (1989) continues to be the primary source for nutritional information about horses.
The 1998 Web version of this publication can be found at: http://orsted.nap.edu/openbook.php?record_id=1213&page=R1
The 2006 revision is available at: http://www.nap.edu/catalog/11653.html
