Fecal Excretion Pattern of Chromic Oxide Administered to Hereford Heifers in a Completely Pelleted Ration

Chromic oxide (Cr2O3) at a level of 0.5% was mixed uniformly into a pelleted ration and fed to six Hereford heifers. The feeding schedules employed were (a) limited-fed once daily, (b) full-fed once daily, (c) full-fed twice a day and (d) ad libitum. Chemical analyses of feces samples collected at 3-hour intervals for 48 hours indicated that a significant time-concentration variation occurred in the fecal pattern of Cr2O3 excretion even though the indicator was mixed into the entire ration. Furthermore, these variations in Cr2O3 excretion appeared to be influenced by the feeding schedules. The magnitude of the variation in fecal Cr2O3 concentration during a 24-hour period encountered in this experiment would preclude the indiscriminate sampling of feces for digestion trials as regards time. A later trial was conducted with two sets of identical twin beef steers which were fed twice-a-day a predominantly roughage diet which was ground, mixed with Cr2O3 and pelleted. Analyses of feces samples collected in the morning and afternoon for 8 days showed Cr2O3 concentrations which tended to support the type of excretion pattern found in the heifers fed twice-a-day.