A recently completed study of the accuracy of USDA Feeder Cattle Grade Standards revealed the system works like it is intended, with graders placing frame scores on feeder cattle to estimate the live weight of a fed steer or heifer when it reaches 0.50 inches of fat.
“The first conclusion to be drawn from the study is the USDA frame score is very predictive of bodyweight,” says feedlot specialist and associate professor Chris Reinhardt of Kansas State University Extension. “What is essentially a subjective score on a feeder calf by a human is actually statistically accurate 80 to 90 percent of the time. We were very pleasantly surprised by that.”
The study was conducted by Reinhardt and Darrell Busby, coordinator of the Tri-County Steer Carcass Futurity Cooperative, operating out of the Iowa State University Outreach Armstrong Research Farm near Lewis, Iowa. Initiated by the USDA, it compares actual carcass data from 23,057 head of beef cattle harvested between 2002 and 2011 with USDA Feeder Cattle Grades of those animals.
“We studied full carcass data and feedlot growth information collected by the Futurity and compared it to the Feeder Grade frame and muscle scores,” Busby says. The cattle in the database come from 16 states — two-thirds from the southeastern United States and one-third from the Midwest. The largest groups were from Georgia, Iowa, Missouri, Virginia, Indiana and Kentucky. Seventy-two percent were steers and 28 percent heifers, harvested at 375 to 525 days of age. Final weights in the study were adjusted to 0.50 inches of back fat for consistent comparisons.
Results of the study cement the USDA graders’ role in the beef cattle marketing system.
“It’s a language, and if you can understand that language, you can talk fluently within the industry,” says Corbitt Wall, officer in charge of the USDA’s St. Joseph, Mo., Voluntary Market News Office. He emphasizes the need for keeping the language relevant. “We’re always looking for the opportunity to see if feeder cattle graders are doing a good job of predicting what will be.”
The data speak
“The data show the grading formula and system do work,” Busby says. “The graders do a good job. But small-frame animals are not being identified as accurately as the rest of the population. Perhaps we need to take a closer look at how those smaller-framed animals are being classified.”
The study shows accuracy is high — over 90 percent — for the vast majority of animals, which fall between the middle of medium-frame to the middle of large-frame categories, but accuracy drastically decreases for those outlier animals, especially small-frame cattle.