Date of Graduation

Fall 2008


Master of Natural and Applied Science in Agriculture


College of Agriculture

Committee Chair

Thomas Perkins


Ultrasound, Steers, Harvest, Carcass, Automated

Subject Categories



Yearling beef steers (n=86) representing typical Charolais-cross commercial cattle, were evaluated for body composition measures of muscle and fat deposition utilizing real-time ultrasound measurements. Target harvest date was estimated based on 12th rib fat thickness and weight (approximately 250 days on feed). Steers were harvested 35 days after being scanned with an ALOKA 500V ultrasound unit equipped with a UST-5049 transducer. Images were processed chuteside using Beef Image Analysis (BIA) automated software. Images were also saved to the computer hard drive and manually interpreted using Rib-O-Matic non-automated software. Mean scan live weight and carcass weight was 582.89 ± 36.44 kg and 380.8 ± 28.05 kg, respectively. Mean automated chuteside ultrasound fat thickness (AFTU), ribeye area (AREAU) and percent fat (A%FATU) were 0.88 ± 0.22 cm, 97.19 ± 7.45 cm2, 4.16 ± .48 %. Mean manually interpreted ultrasound fat thickness (IFTU), ribeye area (IREAU) and percent fat (I%FATU) were 0.89 ± 0.24 cm, 96.36 ± 7.45 cm2, 4.40 ± .73 %. Mean carcass measures of fat thickness (FTC), ribeye area (REAC) and percent fat (%FATC) were 1.15 ± 0.35 cm, 94.17 ± 7.45 cm2, 3.91 ± .75 %. Favorable pearson correlations between AFTU and FTC, IFTU and FTC, IREAU and REAC, A%FATU and %FATC, I%FATU and %FATC were 0.80, 0.78, 0.47, 0.59 and 0.69, respectively; whereas, the correlation between AREAU and REAC were lower and less significant at 0.22. These coefficients indicate that the relationship between manually interpreted ultrasound images and harvest carcass attributes were high and statistically significant. However, these results indicate that automated chuteside image processing was not as useful a tool in assessing ribeye levels on steers prior to harvest.


© Joshua John Worthington

Campus Only