Animal Science Department


Date of this Version

January 2005


Published in 2005 Nebraska Beef Cattle Report. Copyright © 2004 The Board of Regents of the University of Nebraska.
Available online at


Five ruminally fistulated steers were fed five finishing diets containing varying levels and sources of phosphorus (P). Diets consisted of 3 brewer’s grits-based diets consisting of one with no supplemental P (0.12) and two supplemented with mineral P (0.27%, and 0.42% P), one corn-based diet (0.30% P), and one diet containing dry distillers grains (0.36% P). As P intake increased, P excretion increased and was positively correlated (r = 0.67; P < 0.01) to P intake. Most of the P excretion was fecal P averaging 88.7% of total excretion. With the exception of steers fed the 0.12% P diet with very little (0.50 g/day) urinary P, steers fed the other treatment diets excreted an average 2.1 g/day via the urine. These data suggest that P intake is positively correlated to P excretion and diet P concentration may impact route of excretion.