Beef Carcass Yield Grading CDE Tutorial By: Jennie Simpson and Dr. Frank Flanders Georgia Agricultural Education Curriculum Office Georgia Department of Education December 2004 Start

Required Ribeye Area (RREA) The average cattle slaughtered has carcass weight of 600 lbs. And a 11.0 in^2 loin eye. For every 25 lb. Increase or decrease from base carcass weight of 600, the required REA (RREA) is adjusted 3.0 in^2.

Yield Grade A numerical value from 1 to 5 based upon the yield of boneless, closely trimmed, retail cut from the round, loin, rib, and chuck. The official USDA grading standards yield grades range from 1.0 to 5.9. The yield grade is rounded to the nearest whole number.

Fat Thickness (FT) Can be an average of three fat measurements or just a single one. Adjust the estimated value up or down depending on the fat covering the rest of the body. Adjustments of 0.1-0.2 are not uncommon.

Ribeye Area (REA) Determined by either a direct grid reading of eye muscle or by a planimeter reading. Most federal graders are familiar enough with estimating area that they do not need the use of a grid. Hot carcass weight can be used to estimate REA (see shortcut method).

Hot Carcass Weight (HCW) in Lb. Required Ribeye Area (In.^2) Short Cut Method Required Ribeye Area Hot Carcass Weight (HCW) in Lb. Required Ribeye Area (In.^2) 525 9.8 550 10.4 575 10.7 Base=600 11.0 (RREA) 625 11.3 650 11.6 675 11.9 700 12.2 725 12.5 How To Estimate Ribeye Area If You Know the HCW A typical carcass is 600 lb and has a 11.0 in^2 ribeye. For every 25 lb. Under the Base weight, subtract .3 in^2 from the 11.0 in^2 ribeye. For every 25 lb. Over the Base weight, add .3 in^2 to the 11.0 in^2 ribeye. Table on Left does the calculations for you.

Short Cut Method Ribeye Area RREA Deviation Adjustment to FYG 11.2 Ribeye Area Adjustment 1. For every 0.3 square inch deviation from the RREA, adjust the final yield grade 0.1. Ribeye Area RREA Deviation Adjustment to FYG 11.2 11.6 -0.4 +0.1 10.9 12.3 -1.4 +0.5 12.4 11.8 +0.6 -0.2

Adjusted Fat Thickness at 12th Rib (In.) PYG Short Cut Method Fat Thickness To Obtain Adjusted Fat Thickness 1. Estimate fat thickness at 12th rib and adjust as necessary as according to the chart on left. 2. For each 0.1 in of adjusted 12th rib fat thickness under 0.6 in, subtract 0.25 yield grade. 3. For each 0.1 in of adjusted fat thickness in excess of 0.6 in, add 0.25 to the Preliminary Yield Grade. Adjusted Fat Thickness at 12th Rib (In.) PYG .1 2.25 .2 2.5 .3 2.75 .4 3.0 .5 3.25 Base=.6 3.5 .7 3.75 .8 4.0 .9 4.25

Short Cut Method Summary of Yield Grade Calculations FT-Base is 0.0 in. to calculate PYG +0.25 to PYG for each 0.1 in^2 over 0.0 inch FT base -0.25 from PYG for each 0.1 in^2 under 0.0 inch FT base HCW- Base is 600 lb. to calculate RREA +0.3 to 11.0 in.^2 REA for each 25 lb. increase over 600 lb. base -0.3 from 11.0 in^2 REA for each 25 lb. decrease under 600 lb. base REA- For each 0.3 in.^2 deviation from RREA adjust Final Yield Grade 0.1 +0.1 to FYG for each 3.0 in^2 under the RREA -0.1 to FYG for each 3.0 in^2 over the RREA KPH- Base is 3.5%, to adjust FYG by 0.1 for each 0.5 % deviation from base +0.1 to FYG for each 0.5% over the base -0.1 from FYG for each 0.5% under the base

YG1 YG2 YG3 YG4 YG5 High Avg. Low Finally, after obtaining the Final Yield Grade follow this chart for scoring the grade as High, Average, or Low YG1 YG2 YG3 YG4 YG5 High 1.0-1.33 2.0-2.33 3.0-3.33 4.0-4.33 5.0-5.33 Avg. 1.34-1.66 2.34-2.66 3.34-3.66 4.34-4.66 5.34-5.66 Low 1.67-1.99 2.67-2.99 3.67-3.99 4.67-4.99 5.67-5.99