Forage Intake and Performance by Beef Heifers Grazing Cool-Season Pasture Supplemented with De-Oiled Rice Bran or Corn

Abstract

The effects of de-oiled rice bran (DORB) and/or corn supplementation on forage intake and performance by replacement beef heifers grazing winter-annual pasture was evaluated in two trials. In Trial 1, 60 crossbred heifers (189 ± 3.8kg) were randomly assigned to one of six 5.1-ha pastures. Treatments included one of the following: 1) DORB, 2) 1:1 (wt:wt) DORB plus corn (DORB + C), or 3) corn; all were fed at 1% BW (DM basis). Heifer BW and ADG did not differ (P=0.30) among treatments on any date. In addition, breeding date (calving date - 283d) was not affected by treatment (P=0.64). In Trial 2, 12 crossbred heifers (234 ± 5.7kg) were used to determine the effects of the supplements on forage intake and digestibility. The treatments were the same as Trial 1 plus a fourth non-supplemented control. Predicted forage OM intake was greatest for heifers on the control treatment (6.0kg/d) and the corn treatment (5.6kg/d) and was least (P<0.05) for heifers on the DORB + C (4.0kg/d) and DORB (3.9kg/d) treatments. Forage OM digestibility was less (P<0.05) for heifers fed the corn treatment compared with those fed the control, DORB + C, and DORB treatments (68.0, 77.1, 73.1, and 75.6%, respectively). Total digestible OM intake was greatest (P<0.05) for heifers fed the corn treatment (5.7kg/d) and least for heifers fed the DORB treatment (3.9kg/d). Supplement effects on forage OM intake and digestibility did not fully explain the similarities in performance. Based on these results, the effect of supplementing forages with DORB warrants further investigation.