First, the carcass weight issue described above is likely pushing a slightly higher proportion of the heaviest carcasses on the right side of the bell-curve over the 1,050 lb. limit. When the steer carcass weight average surpasses 900 lb. this tends to push a few more over the top.
When weights are running especially heavy we’ll then see more carcasses fall above the upper limit for the brand’s acceptable ribeye area window of 10 to 16 square inches. Some carcasses will logically exceed both weight and ribeye size standards simultaneously.
Backfat thickness exceeding 1 inch as measured at the 12th and 13th rib break is also a disqualifying factor for the brand. It’s a risk to longer-fed cattle and those finishing ahead of schedule. Data from 2015, the all-time heaviest carcass weight year, showed that excess backfat accounted for half as many failure rates as carcass weight and ribeye size when it came to CAB certification.
Finally, the feedyard sector is now working through finishing the oldest demographic of fed cattle that they’ll collectively feed for the year. The tail end of yearling cattle placed on feed in the fall are now being harvested and reports from the field suggest a slightly higher rate of the resulting carcasses missing the CAB mark due to advanced maturity. It tends to happen at this time every year in a seasonal pattern but likely at a bit higher rate this year than normal.
With this said, a higher rate of fed cattle harvest over the past 8 weeks has resulted in a total CAB supply slightly larger than a year ago even though the rate of carcass certification is lower. Prime and Choice grade percentages have returned to roughly the same as a year ago. Inadequate marbling is always the primary reason carcasses miss the CAB mark (roughly 90% of the time) and it’s not currently the factor behaving outside of normal seasonal expectations. As a result, it appears that declining carcass weights and moving into the younger calf-fed population of finished animals would bring the acceptance percentage in line with expectations.