Department of Animal Science


Date of this Version

January 2005


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


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.