High-fibre high-lipid by-product pellets containing calcium oxide-treated oat hulls as a partial replacement for barley grain in finishing diets for beef cattle

Abstract

Two studies were conducted to evaluate the effects of treating oat hulls with calcium oxide (CaO) prior to inclusion in a high-lipid by-product pellet (HLP) on dry matter intake (DMI), ruminal fermentation, and total-tract digestibility (Study 1) and growth performance (Study 2). In Study 1, six ruminally cannulated heifers were used in a replicated 3 × 3 Latin square design. Study 2 used 210 steers in 21 pens in a 113 d finishing study. Dietary treatments for both studies included a barley-based control diet (CON), a diet where HLP partially replaced barley grain (NT-HLP), and a diet where HLP contained oat hulls treated with 7.5% CaO [dry matter (DM) basis; CaO-HLP]. For Study 1, DMI and ruminal pH were not affected. Apparent total-tract digestibility of DM and organic matter (OM) were greater (P < 0.05) for CON than NT-HLP and CaO-HLP. In Study 2, final body weight tended to be greater for NT-HLP and CaO-HLP than CON (P = 0.065). For CaO-HLP and NT-HLP, DMI was greater than CON (P < 0.01), but average daily gain (ADG) (2.0 kg d−1) and gain:feed (G:F) (0.16 kg kg−1) were not different. Thus, HLP can partially replace barley grain in finishing diets without negatively affecting ruminal fermentation or growth performance, but treatment with CaO has no effect.