Date of this Version
Sixty head of crossbred heifers (614 lb initial BW) were individually fed one of five levels of phosphorus of 0.10, 0.17, 0.24, 0.31, 0.38 % of diet DM with supplemental P from monosodium phosphate. Heifers were fed an energy-dense diet composed primarily of corn starch and corn fiber to minimize P from corn. When compared to the other four levels, heifers fed at the 0.10 % P level had lower DMI, ADG and final BW. Heifers fed 0.10%P had lower plasma P concentration. Breakpoint analysis of ADG suggests that the P requirement for finishing heifers is 0.115% P of diet DM within the range of 8.2 to 10.3g P/day (0.104 and 0.127% P on a DM basis).