Influence of method of supplementation on the utilization of supplemental fat by feedlot steers

摘要: Seventy-two Holstein steers (273 kg) were used in a 151-d feeding trial to evaluate the influence of method of fat supplementation on growth-performance. Dietary treatments consisted of 1) control diet (no supplemental fat), 2) 5% yellow grease (YG) on grain (YG was first mixed with a portion of the steam-flaked corn in the proportion 25% YG to 75% corn, prior to adding other dietary ingredients), and 3) 5% YG on ration (YG was added to the mixer as the next to the last step, prior to adding molasses.). There were no treatment effects (P>. 10) on ADG. The addition of 5% YG decreased (6.3%, P<. 01) DMI, and increased feed efficiency (4.7%, P<. 01) and diet NE (5.7%, P<. 01). There were no effects g (P>. 10) of method of fat supplementation on growth-performance. Six Holstein steers (313 kg) with cannulas in the rumen and proximal duodenum were used in a replicated 3 X 3 Latin square design experiment to evaluate treatment effects on digestive function. There were no treatment effect (P>. 10) on ruminal digestion of starch or N. Supplemental YG decreased ruminal digestion of OM (10.4, P<. 01) and ADF (36.7%, P<. 10). There were no treatment effects (P>. 10) on post-ruminal digestion of OM, starch, ADF and lipid. However, saturating a portion of the grain with fat decreased slightly (2.7%, P<. 10) post ruminal digestion of N. Supplemental YG decreased (P<. 10) total tract digestion of OM (1.8%) and ADF (13.9%). It is concluded that there are no positive associative effects of adding YG directly to steamflaked corn on growth-performance or digestive function.