Beef grading is a skill that takes many elements of the carcass into consideration.
Ty Lawrence, professor of animal science at West Texas A&M University, broke it down for attendees at the recent virtual Cattle U and Trade Show event. The event was sponsored by High Plains Journal.
When animals are sent to harvest, Lawrence said, there’s a number of characteristics evaluated. Things like carcass size differences, weight and marbling scores, as well as yield grade, all influence what the end product will be.
“I like to teach students that the quality grade is effectively an indicator of how good the carcass is, and the yield grade is an indicator of how much we’re going to be able to put into the box as a percentage of the original carcass weight,” he said.
Grading is broken down into two primary components, quality and yield grade.
“The quality system is paramount on an improvement in the finished outcome of an animal,” he said. “The pinnacle of that is what we call prime, the highest quality grade, then followed by choice select and standard.”
On the other side of the system is commercial, utility, cutter and canner. This is reserved for animals that are older in age and typically culled from the herd.
Yield grades are from 1 to 5, with one being the highest yielding and 5 being the fattest animal.
Since December 2017, an animal’s age has been determined by dentition, where before age was evaluated by skeletal maturity and lean maturity.
“The addition of the dentition system improved our homogeneity of the animal and reduced some of the subjectivity inherent in those skeleton lean ossification systems,” he said.
Those animals with all their baby teeth or zero permanent incisors are less than 24 months of age. Those with two to three permanent teeth and six remaining baby teeth indicate an age greater than 24 months but less than 30 months. And when there’s three or more permanent incisors, the animal is considered greater than 30 months but less than 38 months of age.
“So that’s now a new demarcation of quality versus what we’ve done in the past,” he said. “Animals that have two, one or zero permanent teeth are eligible for Prime, Choice, Select, Standard, whereas animals that have three or more permanent incisors go back to the traditional system of bone ossification and lean maturity evaluation.”
Very high quality marbling is indicative of slightly abundant, moderately abundant—and those rankings of abundance score categorizes them as prime.
“I would like you to think of a white tablecloth restaurant, very high-end product,” he said. “Actually not a product that commonly stays in the Midwest. Think of New York, Chicago, San Francisco, Los Angeles, Houston, Dallas, Miami, those types of markets typically utilize most of the Prime product.”
Right now there’s just under 10% of cattle harvested daily that are Prime.
Those cattle who aren’t quite as marbled as their prime counter parts, fall into Premium Choice and Choice. These are about 73% of the daily harvest—about 30% at Premium Choice and a little over 40% at choice.
“The Premium Choice market has traditionally been middle tier restaurant quality beef,” he said. “Think something like an Outback restaurant. Whereas, low Choice beef has traditionally been a daily restaurant beef, but we’re seeing a greater and greater proportion of Choice beef now reaching our supermarket shelves.”
Select product has lower marbling and equates to about 14.25% of the market.
“Select was traditionally supermarket beef, and that is still where you can find it,” Lawrence said. “As well as some lower price point restaurants.”
The last ranking is “no roll” and this indicated the beef product was not graded. Just under 3% of the beef supply is no roll.
“Now I kind of humorously, but somewhat truthfully tell students that no roll beef is served to prisoners and schoolchildren,” he said. “The point being, no roll beef is traditionally lower price point, and it’s served or sold to institutions that are seeking a lower price point option.”
Bone ossification has been largely replaced by the dentition when determining maturity, but it remains important. The bone ossification is evaluated by the cartilaginous tips that are at the ends of the spinous processes.
The second part of that original maturity system is a lean maturity score. As animals age, the concentration of myoglobin increases in the muscle tissue. For example, meat from veal calves is very light pink in color very similar to pork, while a cull cow—12 to 16 years of age—would have much darker meat.
They then give it a maturity score—A through E. A has abundant marbling, while E is practically devoid.
“There are 10 degrees of maturity and 10 degrees of marbling that are an option. So it can get quite complicated if you’re trying to find an exact quality grade based on an individual maturity and marbling score,” he said.
Yield grade is a measure of how much beef is going to go into a box and it is based on carcass weight. The single most important outcome, Lawrence said is backfat thickness.
“There’s a linear measure of backfat observed on the animal between the 12th and 13th ribs,” he said. “Second to that is the relationship between the ribeye area and hot carcass weight, and finally is an estimation of the percentage trim fat in the kidney channel pelvic channel, and the heart cavity.”
Most cattle in the United States are in the YG3 category, just under half. YG1 is 4.1%, YG 2 is 32%, YG 4 is 12%, and YG 5 is 2.3%. Lawrence said, in practice, measurement of this fat thickness can be done with a ruler, but technology is more precise.
“This is something that our new camera technology can do in an instant, and a grader can estimate with very good precision as well,” he said.
Also part of this is the assessment of the cross section rib eye area. USDA uses a dot grid, where one dot represents one-tenth of a square inch.
“Again, that can be done very accurately with the dot grid,” he said. “The camera can do it with extreme precision and a grader can do it with very good precision as well after years of training.”
Estimating kidney, pelvic and heart fat gets a little more tricky.
“This is probably without much argument, the most subjective portion of our yield grade, because we’re guesstimating the percentage of the carcass weight that is contained within the kidney area, the pelvic channel, in the heart fat,” he said.
Kylene Scott can be reached at 620-227-1804 or [email protected].
