We evaluated beef carcass data (12th rib
fat thickness, hot carcass weight, ribeye area,
percentage of kidney-pelvic-heart fat, USDA
yield grade, and USDA quality grade) from
60,625 A-maturity steer and heifer carcasses.
Data were analyzed to evaluate changes in
quality grade with increasing fat thickness,
changes in cutability indicators across quality
grades, and the association of hot carcass
weight with ribeye area. Percentage of
USDA Standard and Select carcasses decreased,
while Low Choice and Premium
Choice increased as fat thickness increased.
Percentage of Low Choice remained steady
for fat thickness of 0.56 - 0.60 in. and higher.
Percentage of yield grade 4.0 or greater
carcasses increased dramatically as fat thickness
increased beyond 0.60 in. Fat thickness,
hot carcass weight, percentage of
kidney-pelvic-heart fat, and USDA yield
grade increased, while ribeye area decreased
as quality grades improved. The association
between hot carcass weight and ribeye area
differs from USDA requirements. Our recently
collected data indicate that as hot
carcass weight increases, ribeye area increases
at a slower rate than indicated by
USDA guidelines. Feeding cattle to a backfat
thickness of 0.51-0.55 in. will maximize
quality grade while minimizing discounts for
yield grade 4.0 or higher.
