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Effects of Source and Level of Dietary Roughage and Ractopamine (Optaflexx) Supplementation on Growth Performance, Carcass Characteristics and Meat Quality in Beef Cattle

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dc.contributor.advisor Mandell, Ira B.
dc.contributor.author Glanc, Danielle Laura
dc.date.accessioned 2013-01-29T14:00:08Z
dc.date.available 2013-01-29T14:00:08Z
dc.date.copyright 2013-01
dc.date.created 2013-01-18
dc.date.issued 2013-01-29
dc.identifier.uri http://hdl.handle.net/10214/5386
dc.description.abstract A high moisture corn/soybean meal-based finishing ration was used to examine the effects of roughage source (corn silage, alfalfa hay), level of dietary roughage (8, 16, 24%), and ractopamine supplementation (none, Optaflexx) on growth performance, carcass traits, and beef quality for finishing 108 steers and 24 heifers (initial BW = 308 kg). Cattle were allocated by gender to 12 management regimen subclasses. Optaflexx (trade name for ractopamine hydrochloride) was fed over the last 28 d on feed with cattle marketed after common days on feed. Growth performance (ADG, feed intake, and feed efficiency) and carcass traits were assessed on an individual animal basis. A primal rib and semitendinosus (ST) muscle from each animal were processed at the University of Guelph Meat Laboratory for carcass and meat quality evaluations. Tenderness was determined using shear force assessment of product aged 7, 14, and 21 d. Average daily gains were similar (P > 0.27) across main effects while use of corn silage as the roughage source decreased (P < 0.001) dry matter intake and improved (P < 0.001) feed efficiency compared to feeding alfalfa hay. Roughage level and beta agonist supplementation did not affect (P > 0.13) dry matter intake or feed efficiency. When the last 28 days on feed were examined, Optaflexx supplementation increased (P < 0.001) weight change, ADG, and improved feed conversion, while DMI remained unchanged (P > 0.373). Carcass traits including hot carcass weight, grade fat, longissimus muscle area, marbling, and body composition as assessed by rib dissection (% lean, fat, bone) were not affected (P > 0.14) by roughage level, source, or use of Optaflexx. Fat partitioning and liver abscess scores were unaffected (P > 0.09) by source and level of roughage fed, and use of Optaflexx. Source and level of dietary roughage did not affect color (P > 0.21) or shear force (P > 0.20) values for longissimus (LM) and semitendinosus (ST) steaks. Lower DMI and better feed conversion can be achieved using corn silage as the roughage source, while inclusion of up to 24% roughage in finishing diets may not negatively impact gains, carcass characteristics or beef quality. Beef producers may be able to increase amounts of roughage in the diet to lower cost of production without compromising growth performance and carcass and meat quality. en_US
dc.language.iso en en_US
dc.subject beef cattle en_US
dc.subject ractopamine en_US
dc.subject roughage level en_US
dc.subject alfalfa hay en_US
dc.subject corn silage en_US
dc.subject shear force en_US
dc.title Effects of Source and Level of Dietary Roughage and Ractopamine (Optaflexx) Supplementation on Growth Performance, Carcass Characteristics and Meat Quality in Beef Cattle en_US
dc.type Thesis en_US
dc.degree.programme Animal and Poultry Science en_US
dc.degree.name Master of Science en_US
dc.degree.department Department of Animal and Poultry Science en_US
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