Beef Tenderness Study Looks
At Usefulness Of Gene Markers

DENVER — The first phase of a 42-month research project recently launched by the National Cattlemen’s Beef Association is looking for the answers that can guarantee a juicy, tender steak every time.

The three-part checkoff-funded study ultimately hopes to validate the presence of specific gene markers in the offspring of selected bulls, proving that these qualities are heritable traits.

Researchers will examine the DNA of 6000 calves sired by select bulls to determine if 10 gene markers already identified in research at Texas A&M are present. Two of those traits are closely associated with muscle tenderness as measured by Warner-Bratzler shear force test, a laboratory test designed to measure the tenderness of meat by measuring the force needed to cut it using a blunt blade. Shear forces of less than 10 pounds are considered acceptable. Researchers also will be looking for two different gene markers linked to steaks that scored well when rated by tasting panels using an evaluation system developed by the American Meat Science Association.

In recent years, the industry has pursued "guaranteed tender" products through instrument testing, aging, marinades and genetics. Heritable traits, such as the ones the researchers hope to find, are recorded in expected progeny difference scores, which are an estimate of a sire’s ability to pass along certain traits to its offspring. The study also would determine the economic cost of implementing EPDs for carcass traits. Breed associations that participate in the study will be able to develop EPDs for carcass traits for their specific breeds from a carcass information database developed during the study.

For instance, one breed may want to focus on increasing the marbling score of its cattle, the trait that gives a steak its juicy taste. A different breed may look at the data and decide it wants to increase the size of the ribeye area, a highly valued beef cut. Each of the breed associations involved in the study will find out if the tenderness gene markers were identified in their animals.

A palatability study by Dr. Daryl Tatum of Colorado State University identified genetics as one way the beef industry can change the quality and tenderness of beef. In Tatum’s study, the top 25 percent of sires in one sub-group reduced tough eating experiences to one in 100 for strip steaks.

For a breed to participate, it will have to supply enough semen from 10 bulls to produce 50 calves from each bull. A total of 500 head per breed will be evaluated for carcass traits, including tenderness, and for the presence of the 10 genetic markers. A total of 6000 head will be evaluated in this segment of the study.

Another 5000 head will be evaluated for carcass traits and tenderness and will be used by breed associations to compute their own EPDs. A bull in this portion of the study would have to sire 25 offspring. With some cattle already in the pipeline, it may be possible to have data on the first 2000 head collected by the end of September.

The Beef Promotion and Operating Committee in May approved the $206,000 first phase of the study. The total projected cost of the study is approximately $930,000, so subsequent funding requests will be needed over the next three years.