Comparison of Pre-Yearling, Yearling, and Post-Yearling Ultrasonic Measurements of Body Composition in Brahman Bulls

Date of Graduation

Summer 2005


Master of Natural and Applied Science in Agriculture


College of Agriculture

Committee Chair

Thomas Perkins


The objective of this study was to compare ultrasonic measures of body composition in Brahman cattle at various stages of development. There were three individual scan sessions taken on Brahman bulls (N=72). The serial measurements were taken every two months (beginning mean age of 11 months and mean ending age of 15 months). The animals used in this study were provided by the J.D. Hudgins Ranch in Wharton, Texas. Pre-yearling, yearling, and post-yearling images were collected and interpreted by the same technician. A positive and significant correlation existed between all pre-yearling, yearling, and post-yearling ultrasonic measurements of body composition within each specific straight (e.g. FTU1 and FTU2 = 0.542; FTU1 and FTU 3 = 0.589; FTU2 and FTU3 = 0.635). Significant correlations existed between post-yearling weight (WT3) and post-yearling ultrasound measures of ribeye area (REAU3), fat thickness (FTU3), and rumpfat (RFU3) (0.676, 0.432, and 0.408, respectively.) The correlation between post-yearling percent intramuscular fat (%FATU3) and REAU3 was low (0.013). The correlations between REAU3 and FTU3, and REAU# and RFU3 were 0.314 and 0.281, respectively. A moderately positive correlation existed between FTU3 and %FatU3 (0.262). These data suggest that ultrasound was effective in measuring changes in body composition traits of external fat thickness, ribeye area and rumpfat. However, the technology was ineffective in measuring differences in intramuscular fat deposition in pre-yearling, yearling, and post-yearling Brahman bulls.


Brahman, ultrasound, serial-measurements, ribeye, marbling

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© Tracy D. Jennings