Is phosphorus a problem when feeding distillers grains?
— Fermenting the starch in corn to ethanol concentrates phosphorus in distillers grains about three times. Concern has been expressed that feeding distillers grains will result in overfeeding phosphorus and increase its concentration in manure, causing an environmental problem. Equations from the National Research Council’s Nutrient Requirements of Beef Cattle were used to predict phosphorus retention and excretion of finishing cattle growing at different rates and different stages of maturity on a farm with a simulated 1,000 head feedlot. Calculations show that if the feedlot is located on the farm from which all the feed is harvested and concentrations of phosphorus in the soils are adequate but not excessive, manure from the feedlot would not replace all the phosphorus removed by the corn crop needed to feed the cattle and produce the grain for ethanol. This project indicates feeding distillers grains would not cause an environmental problem, but does require each feedlot to develop
