The 8th Revised Edition of the Nutrient Requirements of Beef Cattle: Byproducts and feed composition

Abstract Text:

Byproduct feeds are important in beef cattle production, often providing cost-effective energy and protein. The focus of the review in the 8^th revised edition was on corn and soy byproducts, as corn and soybean production are the two largest crops produced in the U.S. Use of distillers grains plus solubles, distillers solubles, corn gluten feed, Sweet Bran (Cargill corn milling, Blair, NE), soybean hulls, and glycerin was reviewed. The focus for grain milling byproducts (distillers and gluten feed) was on protein characteristics and use as a protein or an energy supplement, and to replace grain in finishing diets. Effects of initial grain used to produce ethanol on distillers grains characteristics was also reviewed. Associative effects of using grain milling byproducts was reviewed to illustrate the important interactions of corn processing, roughage inclusion, and dietary inclusions relative to energy content realized from distillers grains and corn gluten feed. Similar to the 7^th Revised Edition of the Beef NRC, a comprehensive feed composition review was conducted. Data were summarized from 3 commercial laboratories that included 170 feeds. Nutrient data on DM, ash, TDN, DE, ME, NEm, NEg, sugar, starch, fat, NDF, ADF, lignin, CP, RDP, RUP, soluble CP, ADIN, and minerals (Ca, P, Mg, K, Cl, S, Co, Cu, I, Fe, Mn, Mo, Se, and Zn) were provided. Considerable effort was made to ensure feeds had proper nomenclature and to avoid duplication by evaluating normal distribution, mean, and SD. Feeds with less than 20 entries were removed from the database. Likewise, nutrient values greater or less than 3.5 SD were removed from the database, but only for that nutrient within a particular feed. Once the final data were available, mean, SD, and sample size were calculated and reported, and composition data for these 170 feeds was included in the computer model database. Feed composition data should only be used as a guide in the absence of feed analysis and to indicate which nutrients are variable and may require assay before formulation. These data can also be used to compare analyzed nutrients to a known database. Additionally, grazed forages from different regions were provided from the literature, and focused on masticate collections when available. Grazed forage data only include TDN, NDF, and CP but illustrate how season and region can affect grazed forage quality.

Keywords: beef cattle, byproducts, feed composition