Effect of Increasing Supplemental Rumen Undegradable Protein (RUP) on Performance of Calves Fed a Silage Growing Diet

A growing study evaluated the effects of increasing supplemental rumen undegradable protein (RUP) on performance of calves fed an 85% corn silage diet. Five levels of supplementation were evaluated with 12 individually fed steers per level of supplement. Supplement levels consisted of 0, 3.25, 6.5, 9.75 and 13% supplemental RUP (% of diet DM) fed as a blend of 60% Soypass and 40% Empyreal. Increasing supplemental RUP in the diet increased ending body weight and average daily gain linearly, and decreased F:G linearly while DMI remained constant among treatments. As cattle grew from 600 to 730 lb, F:G was improved 30% by supplying RUP. Th e same amount of RUP improved F:G by 11% as cattle grew beyond 730 lb. By meeting MP requirements, supplementing RUP linearly improved both ADG and F:G of growing calves, especially early in the growing period