Performance of growing steers fed quackgrass hay supplemented with canola meal

Abstract

Sixteen large-frame crossbred beef steers (282 ± 5.5 kg) were used to determine the effect of canola meal (CM) supplementation on voluntary intake, average daily gains (ADG) and digestibility in growing cattle fed quackgrass (Agropyron repens) hay harvested at early heading. All animals received the hay ad libitum during the 81-d experiment. Seven steers received a supplement of 400 g (as fed) of CM per head daily. Average daily gains were 60% higher for steers receiving CM supplementation compared to those receiving only hay (0.93 vs. 0.58 kg, respectively, P < 0.001). Canola meal supplementation tended to improve hay intake by 8% (P = 0.06) when expressed in terms of g kg−0.75. Feed efficiency was 37.6% higher following CM supplementation (P < 0.001). Apparent DM and energy digestibilities were not different between diets, but protein digestibility was 2.9% higher for steers receiving CM (P < 0.01). On the other hand, apparent digestibilities of fibre components were lower in steers receiving CM (2.7% for neutral detergent fibre, P < 0.05, and 6.4% for acid detergent fibre, P < 0.001). Digestible energy of the total diets was only slightly higher for the one supplemented with CM (P = 0.10). The increase in ADG observed was partially explained by the increase in voluntary intake of the diet following CM supplementation. Key words: Canola meal, quackgrass hay, cattle, growth