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

Abstract

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. Copyright © . .