339 - Growth Performance and Carcass Characteristics of Feedlot Beef Yearling Steers Offered Finishing Diets with Direct Fed Microbial Mixtures

Monday, June 27, 2022

10:35 AM – 10:50 AM CT

Location: Oklahoma City Convention Center, 301 A/B

Presenting Author(s)

AL

Alejandra M. Lopez

Master's Student
Texas Tech University
Lubbock, Texas

Author(s)

JO

Jhones O Sarturi, n/a

Associate Professor
Texas Tech University
Lubbock, TX
DH

Darren H. Henry

Department of Animal and Dairy Science, University of Georgia – Tifton Campus, Tifton, GA 31793-5766, USA
Tifton, GA
FC

Francine M. Ciriaco

University of Georgia
Tifton, GA
BJ

Bradley J. Johnson, PhD

Professor
Texas Tech University
Lubbock, TX
Dale R. Woerner, PhD

Cargill Endowed Chair in Sustainable Meat Science
Texas Tech University
Lubbock, TX
Kaliu G. Scaranto Silva

Masters Student
Texas Tech University
Lubbock, Texas
Kaue Tonelli Nardi

Masters Student
Texas Tech University
Lubbock, TX
CR

Camron J. Rush

Undergraduate Student
Texas Tech University
Lubbock, TX
BR

Barbara Rodrigues

Texas Tech University
Lubbock, TX
SP

Sarah Peters

Texas Tech University
Lubbock, TX
MD

Mikala Di Manna

New Mexico State University
Las Cruces, NM
Andrea M. Osorio-Doblado, MA

Research Assistant
University of Georgia
Tifton, GA
KC

Kymberly Coello

University of Georgia
Tifton, GA
Angel A. Quijada

Research Scholar
University of Georgia
Tifton, GA

Abstract: The effects of dietary inclusion of live bacteria on feedlot beef cattle growth performance and carcass characteristics were evaluated. Crossbred-Angus yearling steers (n = 192; initial BW = 409 kg ± 8 kg) were blocked by body weight (BW) and randomly assigned into 48 pens (4 steers/pen; 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered ad libitum once daily containing the following treatments: 1) Control, in which no direct fed microbial (DFM) was offered (lactose as carrier only); 2 and 3) Probiotic mixtures at distinct concentrations [Mixture A and B, at 2g/animal-daily (lactose used as carrier)]. Orts DM were quantified daily and subtracted from total dietary DM offered to calculate DM intake. Two-day consecutive unshrunk BW were recorded before feeding on d 0, 30, 60, 90, 121, and 153 (prior to shipment to a federally inspected slaughter facility). Data were analyzed using the GLIMMIX procedure of SAS and pen was considered the experimental unit, in which F-test protected pre-planned contrasts comparing control versus DFM mixture-A and control versus DFM mixture-B were used. Steers offered mixture-A increased carcass-adjusted ADG (P = 0.03) by 6.7%, gain efficiency (P < 0.01) by 6%, tended to increase carcass-adjusted final BW (P = 0.07) by 15kg and hot carcass weight (P = 0.07) by 10kg. The overall (d 0 to end) DM intake (P = 0.36) was not affected by treatment; however, a subtle (1.2%) decrease (P < 0.01) during the initial 30 days for steers offered DFM mixture-B was observed. Carcass variables (dressing percentage, 12^th rib fat, longissimus muscle area, marbling, yield grade, and liver scores) were not affected (P ≥ 0.13) by treatments. Growth performance was improved with DFM mixture-A which seemed to positively affect carcass weight without inducing deleterious effects on other carcass characteristics.