Skip to main content
ARS Home » Research » Publications at this Location » Publication #217108

Title: Predicting back fat thickness in beef cattle using A-mode ultrasound

item Phillips, William
item Coleman, Samuel
item Chase, Chadwick - Chad
item Riley, David

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/6/2007
Publication Date: 2/4/2008
Citation: Phillips, W.A., Coleman, S.W., Chase, C.C., Riley, D.G. 2008. Predicting back fat thickness in beef cattle using A-mode ultrasound [abstract]. Southern Section of American Society of Animal Science Annual Meeting, San Antonio, TX, February 2-5, 2008. 86(1):25.

Interpretive Summary: Abstract only

Technical Abstract: Because fat thickness in feedlot cattle can be a predictor of carcass quality and yield grade, estimates of fat thickness during the later stages of the finishing period can be used to make marketing decisions. Ultrasound technology is a nondestructive and humane technique used to estimate fat thickness in live animals. Currently, real time ultrasound (B-mode) technology is used to create an image from which fat thickness and many other carcass characteristics are calculated. However, B-mode equipment is expensive. Although amplitude mode (A-mode) ultrasound provides less information than B-mode, equipment cost is less. The objective of this experiment was to determine if A-mode ultrasound could be used to predict carcass fat thickness in beef cattle. Ultrasound measures of fat thickness (FTU) were taken on 81 feedlot steers and 11 feedlot heifers just prior to harvesting and correlated with carcass fat thickness (FTC). Calves used in this study were sired by Angus (A), Brahman (B) or Romosinuano (R) bulls. Dams were A, B, R, AB, AR, BA BR, RA, or RB? Calves were born in late winter at the Subtropical Agricultural Research Station Location, weaned in late September of 2006 and shipped 2025 km to El Reno, OK for growing (October through April) and finishing (April through August). Calves were fed a high energy finishing diet for 122 d ± 20 SD. Calves were considered finished when visual estimates of fat thickness over the 12th to 13th rib section was >10mm. A-mode ultrasound measures of fat thickness were made the day before harvesting and FTC measurments were made 72 h after harvesting. Fasted pre-harvest BW and hip height (mean ± SD) were 529 ± 60 kg and 136 ± 7.4 cm. Hot carcass weight, dressing percentage, FTC were 331 ± 41.3 kg, 62.4 ± 1.91%, and 15.4 ± 6.15 mm, respectively. Estimate fat thickness (mean ± SD) using ultrasound was 13.4 ± 2.38 mm. Correlation coefficients for FTC and FTU were 0.624 (P < 0.01). Although this correlation coefficient is slightly lower that previous values reported by other labs derived using B-mode ultrasound, we concluded that A-mode could be a useful lower cost tool for estimating fat thickness in feedlot cattle. Corrected 10-15-07