Ultrasound rib eye area
Phenotype
Accurate live animal, ultrasound estimation of ribeye area is dependent on three major items: clear and distinct medial and lateral end borders, not being over any portion of 12th or 13th rib, and good transducer-animal contact. The presence of well-defined intercostal muscles under the longissimus dorsi is an indication that the transducer is properly aligned directly between the 12th and 13th ribs for this measurement.
Adjusted Value
Contemporary Group
Animals of the same sex, reared and managed together up until the time of scanning form a contemporary group. Scanning contemporary group definition includes the following: herd code, weaning date, weaning management group (pasture, creep, non-creep, etc.), scanning date, and post-weaning management group designation. For animals scanned at a central test, the contemporary group definition for an animal should include its herd of origin and other birth and weaning contemporary group information.
Genetic Evaluation
Given the ultrasound measure of ribeye area is an indicator of the economically relevant trait of carcass ribeye area, it is generally included in multi-trait models that include carcass ribeye area and potentially other traits such as carcass weight. There are no maternal effects fitted for ultrasound or carcass traits given the maternal influence declines post-weaning.
