Red Angus Association of America

What is Real Time Ultrasound?

Real time ultrasound consists of sound waves with frequencies above what the human ear can detect. These sound waves are transmitted and received back through the probe or transducer (the rectangular piece applied to the skin of the animal). As the sound waves pass through materials with different densities, these sound waves bounce back to the transducer at different rates and the tissue density can be detected. For example, hide fat and muscle have different densities.

Why Do We Scan For Fat Thickness, Ribeye Area, Percentage of Intramuscular Fat, and Rump Fat?

Ribeye Area
Ribeye area is the area of the longissimus muscle that is measured in square inches between the 12th and 13th rib on the beef forequarter (Figure 1). The longissimus dorsi (ribeye area) is the largest muscle in the body, so ribeye area gives an indication of overall carcass muscling. Like fat thickness, ribeye area measurements are positively correlated with pounds of retail product. Ribeye area along with fat thickness and hot carcass weight are used in the current USDA Yield Grade formula which predicts cutability or percentage retail product. Ribeye area is moderate to highly heritable.

Figure 1. Ribeye Area and Fat Thickness

Percentage of Intramuscular Fat
Intramuscular fat is the percentage of fat within the ribeye muscle also known as marbling (Figure 2). Percent IMF has the most influence on marbling score and in turn marbling score has the most influence on USDA quality grade. Marbling is the most important trait measured that directly contributes to beef palatability.

Figure 2. Percentage Intramuscular Fat

Fat Thickness
Fat thickness, also know as rib fat or back fat, is an external fat measurement taken between the 12th and 13th ribs that is measured in inches (Figure 1). Because fat thickness is moderate to highly heritable, the differences found between bulls would be expected to be passed on to their progeny. Fat thickness influences lean meat yield and is highly related to retail product of a beef carcass. However, fat thickness is also an indication of the bull's fleshing ability, and studies have suggested a positive genetic correlation may exist between yearling ultrasound fat thickness and yearling ultrasound ribeye area, weaning weight direct and post weaning gain. Because of this possible confounding effect ultrasound fat thickness is not currently incorporated into the RAAA back fat EPD.

Rump Fat
Rump fat measures the depth of fat at the juncture of the gluteus medius and superficial gluteus medius muscles. It is an external measurement taken from an image collected between the hooks and pins of the animal that is measured in inches. Rump fat coupled with fat thickness is used to determine more accurately the overall external body fat.

What Cattle Should I Scan?

As with any trait, it is necessary to compile data from the entire contemporary group. The more cattle that are measured, the more accurate and useful the information will be. Ideally, all calves should be scanned around twelve months of age, regardless of whether they are to be retained, sold, or culled.

How Do I Utilize Ultrasound Data?

EPDs for any trait give the best overall comparison of an animal within a breed. Carcass EPDs for yearling cattle take into consideration pedigree and individual ultrasound performance. Currently, the Red Angus Association provides animals that are in valid contemporary groups and have parents with numeric accuracy carcass EPDs with P+ interim carcass EPDs. In other words, a calf that has ultrasound data and meets the above criteria will receive carcass EPDs adjusted for individual ultrasound performance as soon as the ultrasound data is processed at the National Office. If carcass EPDs are not available then ratios may be used to evaluate the herd. Ratios rank animals within a contemporary group with age adjustments taken into consideration. Ratios can not be compared with ratios within other contemporary groups. With all that said ultrasound data should be used via carcass EPDs or ratios to rank animals within a herd for selection purposes to increase the genetic value of a herd. Actual trait measurements should not be used for either selection purposes or as a marketing tool.

Real time ultrasound is one of the most useful tools for ranking animals within a group. It allows a producer to know objectively and inexpensively the carcass merit of a potential herd sire or replacement female without harvest. Real time ultrasound offers the seedstock industry one of the most powerful tools for genetic improvement. Therefore, the Red Angus Association strongly encourages producers to participate in the ultrasound program.

APTC Field Technician List

Technician / Location / Phone

David Aborn - Ava, MO - (417) 683-3387

Mike Anderson - Ames, IA - (512) 291-9624

Phil Bailey - Woodbury, GA - (706) 553-5437

Grady Bishop - Manhattan, KS - (785) 532-1171

Bonnie Bradford - St. Marys, OH - (419) 394-5076

Johnna Bruhn - Logan, NM - (505) 487-9266

Trent Callahan - Butler, MO - (660) 679-6139

Russell Coon - Bethel, MO - (660) 284-6473

Clinton Cotton - Hotchkiss, CO - (970) 872-3476

Joel Cowley - East Lansing, MI - (517) 432-5444

Dustin Dean - Lubbock, TX - (806) 780-5355

J C Ellender - Choteau, MT - (406) 466-2985

Tristan Emond - Rapid City, SD - (605) 355-9277

Judi Fahsholtz - Billings, MT - (406) 252-8532

Angie Fink - Curtis, NE - (308) 367-8688

Eric Geving - Cody, WY - (307) 587-3943

Justin Gleghorn - Lubbock, TX - (806) 780-5358

Mark Goes - Beatrice, NE - (402) 223-2433

Chad Gordon - Fletcher, OK - (580) 515-0650

Kristi Gordon - Kensington, KS - (785) 476-2263

Maureen Harkin - Chillicothe, MO - (660) 247-2191

Steven Harrison - Grace, ID - (208) 427-6217

Becky Hays - Diagonal, IA - (515) 231-0480

Craig Hays - Diagonal, IA - (641) 340-4335

Shawn Hays - Diagonal, IA - (641) 340-4335

Mark Henry - Ames, IA - (515) 232-9442

Bill Hilleman - Richland Center, WI - (608) 647-6333

John Huston - Prairie, MS - (662) 369-4426

Les Hutchens - Stillwater, OK - (405) 377-8037

Lance Jefcoat - Prairie, MS - (662) 456-3696

Matt Jones - Franklin, TX - (979) 828-3968

Kristi Kern - Salina, KS - (785) 825-7600

Rethel King - Harrison, AR - (870) 743-3440

Wesley Klipfel - Jackson, TX - (731) 664-7400

Casey Knowles - Oakdale, CA - (209) 848-0278

Steve Krull - Curtis, NE - (308) 367-8688

Matt Lane - Billings, MT - (406) 259-5904

Randall Lester - Beaver, WV - (304) 256-2807

Susan McCalib - Cloverdale, OR - (503) 398-2834

Dallas McDermott - Harlan, IA - (712) 755-2190

Jason McLennan - Fargo, ND - (218) 790-2860

Andy Meadows - Buchanan, VA - (540) 254-2710

Ed Miller - Platte City, MO - (816) 431-2808

Toby Muller - Bridgewater, IA - (641) 369-2829

Angela Nagel - Springfield, SD - (605) 369-2617

Cindy Nagel - Springfield, SD - (605) 369-2628

Scott Nash - Pocatello, ID - (208) 237-9296

James Neel - Beaver, WV - (304) 256-2972

Richard Oglee - Platte City, MO - (816) 431-2808

John Openshaw - Modesto, CA - (209) 522-7742

Joel Packham - Paris, ID - (208) 945-2814

Dan Palmer - Fairfax, MN - (320) 212-4466

Rauhn Panting - Malad, ID - (208) 766-4844

Shelby Parker - Orland, CA - (530) 865-7413

John Parks - Milledgeville, IL - (815) 225-7368

Bob Patacini - Sunnyside, WA - (509) 305-1716

Lorna Pelton - College Station, TX - (979) 255-1544

Tommy Perkins - Springfield, MO - (417) 836-5020

Dean Pringle - Athens, GA - (706) 542-0997

Jim Pritchard - Marlington, WV - (304) 799-4852

Rodger Reitman - Billings, MT - (406) 252-3242

John Riggs - Henryetta, OK - (405) 786-2626

Paul Ritter - Oakley, KA - (785) 672-3411

Raymond Rivale - Des Moines, NM - (505) 487-7494

Bill Rotenberger - Ludlow, SD - (701) 391-2004

Alvin Ruiz - Yoder, WY - (307) 532-3889

Tommy Shields - Mississippi State, MS - (662) 325-5208

Justin Smith - Oakley, KS - (785) 672-3411

Mike Stanek - Huxley, IA - (515) 450-2234

Bob Stevenson - Hobson, MT - (406) 423-5365

J R Tait - Ames, IA - (515) 294-3795

Michael Thompson - Holly Springs, MS - (662) 252-5454

Rhonda Vann - Raymond, MS - (601) 857-2284

Les Wankel - Manhattan, KS - (785) 537-7753

Marlene Wells - Carson, ND - (701) 622-3714

Rod Wendorff - Raymond, Alberta - (403) 752-4066

Bonnie Werner - Diagonal, IA - (641) 340-4335

Roger West - Gainesville, FL - (352) 392-7566

Allen Williams - Mississippi State, MS - (662) 325-7466

C R Williams - Dodge City, KS - (316) 339-6677

Mark Zink - Wayne, NE - (402) 375-2933