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.

Effect of dietary lipid inclusion from by-product-based pellets on dry matter intake, ruminal fermentation, and nutrient digestion in finishing beef heifers

“…The NDF in the diet was; however, largely sourced from non-forage fiber sources such as oat hulls that inherently have a low digestibility (Thompson et al 2000). Low apparent ruminal NDF digestibility has previously been reported for beef heifers when fed byproductpellet based diets (Górka et al, 2015) and altering the digestibility of oat-hulls in the HLP through the use of calcium oxide does not affect growth performance or total tract NDF digestibility when fed to finishing beef cattle (Johnson et al, 2018). However, the low fiber digestiblity observed with in-situ incubation data in the current study suggests that low NDF digestibility may be due to factors other than increasing lipid and inherent digestibility of the non-forage fibre sources used.…”