Validation of real-time ultrasound technology for predicting fat thicknesses, longissimus muscle areas, and composition of Brangus bulls from 4 months to 2 years of age

Abstract

Sixty Brangus bulls were evaluated live using two real-time ultrasound instruments and four technicians to estimate longissimus muscle area (LMA) and 12th rib fat thickness (FT) every 4 mo beginning at 4 and 12 mo of age, respectively, and continuing until 24 mo of age. Ten bulls were slaughtered every 4 mo to determine actual LMA and FT, 9-10-11th rib chemical composition, yield grade (YG) factors, and empty body weight (EBW). Live animal traits were used to predict 9-10-11th rib composition, YG, and EBW. Scanned mean FT was accurate (P less than .05) at 16 mo and was not different (P = .09) from the actual mean FT (95% of the time the error in estimation was less than or equal to .33 cm). Scanned mean LMA was accurate (P less than .05) at 12 mo (95% of the time the error in estimation was less than or equal to 20.0 cm2). Absolute differences between scanned and actual mean FT and LMA were different (P less than .05) from zero for the main effects of month, operator and(or) interpreter, and instrument. Increased level of operator skill did not improve the accuracy of FT or LMA measurements, whereas increased level of skill of the interpreter of scans did improve the accuracy of LMA estimations. There was no difference (P greater than .05) between ultrasound instruments in accuracy of estimating FT or LMA. The most accurate prediction of YG occurred at 12 mo and incorporated LW, hip height (HH), and ultrasound LMA (R2 = .95, SD = .14). The most accurate prediction of EBW occurred at 16 mo and incorporated LW, HH, and ultrasound FT (R2 = .99, SD = 6.65 kg), whereas the most accurate equation for combined slaughter periods incorporated LW, HH, and ultrasound LMA (R2 = .99, SD = 20.71 kg). We conclude that scanning of LMA at 12 mo and of FT at 12 or 16 mo were sufficiently accurate to characterize groups of bulls; however, some individual measurements were quite inaccurate. Measurements at other months should not be considered accurate for either individuals or groups of bulls. Yield grade and EBW can be accurately estimated from live animal and ultrasound measurements, which may be useful in identifying Brangus cattle with superior cutability and may eliminate the need for serial slaughter in research projects.

The prediction of retail beef yield from real time ultrasound measurements on live animals at three stages through growout and finishing

“…They also concluded that scanned measurements estimated carcass yield percentage as accurately as the same measurements taken on the carcass. A similar conclusion was also reached by Faulkner et al (1990), Miller et al (1988), Waldner et al (1992) and Williams et al (1997).…”

Ultrasonography as a predicting tool for carcass traits of young bulls

“…Although some reports show a decrease in accuracy as FT values increase, accuracy increases as cattle approach slaughtering due to a small weight gain variation among animals. Further, the highest carcass FT value found in this study was 7.04 mm for Angus crosses, whereas accuracy starts to be impaired when FT values are higher than 10 mm (Faulkner et al, 1990;Perkins et al, 1992a;Waldner et al, 1992;Bergen et al, 1996).…”

“…Ultrasonography is emphasized within this context as a viable (Frost et al, 1997), reliable and acceptable costeffective technique (Houghton & Turlington, 1992). Ultrasound live measurements can be utilized to estimate muscle growth, predict carcass composition (Bailey et al, 1986;Faulkner et al, 1990;Perry & Fox, 1997;Renand & Fisher, 1997) and yield of commercial meat cuts (Waldner et al, 1992;Hassen et al, 1999b), as well as to estimate animal body condition score and nutritional status (Busboom et al, 2000). Live measurements are taken from the Longissimus dorsi muscle section area (REA), and from the backfat layer thickness (FT) in the same muscle, based on images made between the 12 th and 13 th ribs.…”

Relação entre medidas ultrassônicas e da carcaça de bubalinos Murrah abatidos em diferentes períodos de confinamento

“…As diferenças entre as avaliações na carcaça e por ultrassom dependem da experiência do técnico, das mudanças post mortem, da espessura do couro, do comprimento do pelo, do nível de acabamento, entre outros fatores (Waldner et al, 1992). Entretanto, Waldner et al (1992) avaliaram a utilização do ultrassom em bovinos da raça Brangus em diversos períodos de abate -com as medidas realizadas por vários operadores com diferentes níveis de experiência -e afirmaram que as medidas de área de olho-de-lombo foram subestimadas por todos os operadores, independentemente do nível de experiência, quando a área de olho-de-lombo foi menor que 70 cm 2 . Neste trabalho a área de olho-de-lombo, em todos os períodos de confinamento, foi menor que 70 cm 2 (Tabela 2), confirmando que área de olho-de-lombo menor que 70 cm 2 medida por ultrassom subestima as medidas da carcaça.…”