|Rouquette, Jr, F - TEXAS A&M|
Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 2, 2000
Publication Date: N/A
Interpretive Summary: Real-time ultrasound has potential for measuring compositional traits in grazing experiments. Many small cattle producers are vertically integrating their operations by retaining ownership of their stocker calves in the feedlot. Furthermore, cattle marketing is becoming more value-based. Awareness of body condition and composition generated with their forages and management systems could be helpful in making management decisions. Ultrasound scans were taken at the start and conclusion of two grazing trials with steers; one with bermudagrass that evaluated effects of corn supplementation on steer performance, and the other trial with ryegrass that examined stocking rate and grazing method effects on steer performance. Scans of the ribeye, between the 12th and 13th ribs, showed that backfat depths and ribeye areas increased with higher levels of corn supplementation on bermudagrass and with reductions of stocking rate on ryegrass. Real-time ultrasound can be used as a research tool for determining if compositional traits of feeder calves respond differently to management treatments. This new capability of evaluating compositional traits of live cattle will provide a means of generating information for improving management decisions for cattle with retained ownership through the pasture and feedlot.
Technical Abstract: Real-time ultrasound has potential use for measuring body condition and tissue composition of cattle in grazing trials. Ultrasound scans were collected for yearling steers at the start and finish of two separate grazing experiments to determine if measures of backfat and ribeye can be taken with enough precision to detect treatment effects on these traits. One grazing trial was conducted with bermudagrass that evaluated effects of corn supplementation on steer performance, and the other trial was conducted with ryegrass that examined stocking rate and grazing method effects on steer performance. Linear increases of backfat and ribeye area were observed as level of corn supplementation increased for bermudagrass and as stocking rate decreased for ryegrass. Backfat percentage, on a relative area basis with ribeye area, ranged from 0.1 to 8.1% for the bermudagrass study and did not increase with higher corn supplementation rates. These percentages for the ryegrass study had a wider range of -0.3 to 27.5% and decreased with increases of stocking rate. Results of the study showed that real-time ultrasound can be used for determining responses of compositional traits to treatments in grazing trials.