Using Ultrasound Estimates of Loin Muscle Measurements to Obtain Weight-Adjusted Ribeye Area in Tar...
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Nacaa poster 2011

Published on: Mar 3, 2016
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Transcripts - Nacaa poster 2011

  • 1. Using Ultrasound Estimates of Loin Muscle Measurements to Obtain Weight-Adjusted Ribeye Area in Targhee Rams Janna Kincheloe1, Rodney Kott 2, Lisa Surber 3, and David Notter 4 1Agriculture Extension Agent, Montana State University Extension, Judith Basin County, Stanford, Montana 59479 2,3 Montana State University, Bozeman, Montana 59717 4Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061ABSTRACT METHODS Figure 2. Power adjustment of REA in Targhee ramsIn recent years, ultrasound measurement of ribeye  Forty-two MSU Targhee rams were weighed and 2 4 3.48 3.37area (REA) has allowed objective measurements of measured for REA, ribeye depth, and fat thickness at 1.58 3.09 3.5 2.75important carcass traits to be used in livestock the 12th/13th rib transverse using an Aloka 500V 1.5 3 Power of Scanning Wt.selection programs. However, there are no ultrasound machine with a 12 cm 3.5 mHz linear 2.36 REA, in2 1.37 2.5standardized procedures to accurately ensure probe. 1.9 1.16 1 0.85 2repeatability among technicians, and, due to  Data was collected approximately every 4 weeksdifferences in production and management, no from November through May under a typical ram 0.54 1.5established weight and/or age at which to measure development program for western range rams. 0.5 Power Adj. 1REA. The objective of this research is to develop a  Regression analysis was used to determine the 0.13 Actual REA 0.5recommended method to adjust ram ultrasound relationship between age, weight, and REA and 0 0scanning estimates. Forty-two MSU Targhee rams were develop a weight adjustment factor for REA. 126 146 165 188 201 230measured for REA at 12th/13th rib transverse using Picture 2. Typical ultrasound image Ave. Weightultrasound approximately every 4 weeks fromNovember through May under a typical ram OUTREACH and IMPACTSdevelopment program for western range rams. Data Backfat thickness  In addition to research trial, producer outreachindicated that a 190-lb ram should have a 3-inch REA, efforts have resulted in collection of ultrasound dataand that REA changed by ±0.015 inches for every 10-lb Loin depth of over 1,000 sheep from 26 producers throughoutchange above or below 190 lb. Body weight REA Montana.differences accounted for 67% of variation in REA. Ourultrasound procedures will be used to develop a  One purebred Targhee producer in Judith Basinstandardized protocol for ultrasound scanning of County has noted increased adjusted REA sincesheep and will assist in development of a carcass utilizing ultrasound results in ram selection (Figure 3).merit EPD in the Targhee breed. Figure 3. Average REA in Judith Basin County Targhee rams RESULTS and CONCLUSIONS 3.5OBJECTIVES  Body weight differences accounted for 67% of 3.41The objectives of this research were to: variation in REA. 3.41. Determine if there is a relationship between  Regression analysis indicated that for every 10 lbs. 3.3 REA (in2) weight and/or age and REA ultrasound estimations 3.19 above or below the 190 lb. target there would be an 3.2 3.122. Develop a recommended method to adjust ram adjustment factor of ±0.015 of REA in inches. 3.1 3.03 ultrasound scanning estimates.  At the same degree of maturity, measures of cross- 3This would allow comparisons to be made at sectional area such as REA are expected to be 2.9production sales and allow ultrasound data to be proportional to the 2/3 power of body weight. 2.8incorporated into EPD analyses in the National Sheep  Data in Figure 2 suggests that the ideal scanning 2008 2009 2010 2011Improvement Program (NSIP). weight for these Targhee rams would be between 180 Year and 200 lbs. with limits of 170 to 210 lbs. AdjustedPicture 1. Collecting ultrasound data on a Targhee ram MANAGEMENT IMPLICATIONS REA would be obtained as: 190 lb. Adj. REA =  Ultrasound allows the commercial producer to [(Target weight / Actual weight)0.67 x Actual REA] assess the carcass merit of potential herd sires and to  Use of the above power function as developed by Dr. select rams that will sire lambs with superior carcass David Notter reduces bias made by linear adjustments merit. since growth curves are also non-linear.  Seedstock producers can utilize ultrasound as an additional evaluation tool for potential stud sires and Figure 1. REA and weight of Targhee rams can also select replacement females with balanced 4 3.5 3.5 300 maternal and carcass traits. 3.4 3.5 3.2  Utilizing the power adjustment formula allows 250 3 245 objective comparisons of ultrasound data and hasRATIONALE 2.2 2.4 222 200 been incorporated into catalog information for 2.5 215 REA (in2) The sheep industry is behind the beef and swine potential buyers at the Miles City Ram Sale and other lbs 1.8 180industries where carcass measurements using 2 162 150 production sales. 102 150ultrasound technology are commonly used in livestock 1.5 130  The power adjustment formula provides a 100selection programs. 1 1.2 Ribeye standardized weight range at which rams should be Many sheep breed associations are initiating carcass Weight 50 scanned, and is expected to be incorporated into EPD 0.5value EPD’s (Expected Progeny Differences); however, analysis in the NSIP by the fall of 2011. 0 0there are no standardized procedures for the weight Start Nov. Dec. Jan. Mar. Mar. Apr. Mayand age at which to measure ribeye area. 30th 30th 30th 3rd 31st 28th 25th

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