Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2001
Publication Date: N/A
Interpretive Summary: Real-time ultrasound technology has been used to measure compositional traits of live cattle for purposes of predicting carcass composition and yield. Although real-time ultrasound has been primarily applied to finishing cattle, the technology could also have potential use for estimating compositional traits of stocker cattle. An experiment was conducted to determine if relationships can be detected between ultrasound measures of calves entering the feedlot and the percentage and pounds of carcass retail product. As expected, breed type (Santa Gertrudis and Santa Cruz) had a strong influence on percentage and pounds of carcass retail product. Although percent and pounds of carcass retail product were correlated with body weight and ultrasound measures of ribeye area and external fat, the relationships were rather weak. Breed type and ultrasound measures of calves being removed from pasture/range and placed in the feedyard can provide some information for predicting carcass yield at the conclusion of finishing. Other information, such as frame score and weight gain performance during grazing, etc., will likely be necessary before accurate and precise predictions can be a reality. Development of these models will provide ranchers and small farmers with a management tool for grouping and/or culling their stocker herds on a basis of uniformity and expected production of retail product.
Technical Abstract: Real-time ultrasound has potential in predicting the carcass retail product of feedlot cattle in a late-stage of finish, but it could also have potential use as a management tool for calves entering the feedlot. A study was conducted to determine if relationships can be detected between carcass retail product and ultrasound and body weight measures taken at entrance in the feedlot. Two pens of Santa Cruz steers and one pen of Santa Gertrudis were weighed and ultrasonically scanned on the eighth day after being placed in the feedyard. Carcass data were used to estimate percent and pounds of retail product. Percent retail product was correlated with ultrasound measures of ribeye area (UREA), backfat thickness (UBFT), and rump fat thickness (URFT). Pounds of retail product was correlated with UREA, URF, and body weight (BW). A multiple regression showed relationships between percent and pounds of retail product and UREA, ,URFT, and BW, but the associations were low. Results of the study indicat a potential for using ultrasound measurements of stocker and feeder calves to determine carcass yield potential, but more data and information are needed to improve accuracy.