In vivo estimation of sheep carcass composition using real-time ultrasound with two probes of 5 and 7.5 MHz and image analysis1

Abstract

Ultrasonic measurements were taken on 46 sheep using a real-time ultrasound machine equipped with 2 probes (5 and 7.5 MHz). Measurements of subcutaneous fat thickness (SC) and muscle LM depth (MD) and area (MA) were taken at 2 locations: over the 13th thoracic vertebra (SC13, MD13, and MA13, respectively) and at the interval between the third and fourth lumbar vertebrae (SC34, MD34, and MA34, respectively). Fat thickness was also measured over the third sternebra of the sternum. The relationship between carcass and in vivo ultrasound measurements was high for all the measurements (r(2) between 0.54 and 0.96, P < 0.01). Concerning MD and SC, the 7.5 MHz probe estimates were consistently more precise than the 5-MHz estimates (r(2) increased between 0.09 and 0.13), but the reverse occurred with the MA estimates, although to a lesser extent. Estimates of carcass composition for muscle, subcutaneous fat, intermuscular fat, internal fat, and total fat based on BW explained a large amount of variation in muscle (87%), subcutaneous fat (85%), intermuscular fat (79%), internal fat (74%), and total fat (87%). In most cases (55 of 70) the introduction of one ultrasound measurement in addition to BW in the multiple regression equations further improved the explanation of variation for weight of carcass tissues, internal fat, and total fat. For carcass muscle estimation, the ultrasound measurements of muscle provided an increase of r(2) between 0.05 and 0.10 (P < 0.01). The SC13 and SC34 gave the best improvements in estimating subcutaneous fat, intermuscular fat, internal fat, and total fat (r(2) increased between 0.05 and 0.17; P < 0.01). Prediction of the proportions of the carcass components (internal and total fat from BW) was clearly lower than the prediction of the absolute amounts of these traits. Inclusion of one or more ultrasound measurements in addition to BW increased the predictive ability of the equations. Both probes were useful to estimate carcass muscle depth and area and fat depth, but the 7.5-MHz probe showed a greater ability to estimate depth. For all traits, the stepwise procedure demonstrated that the best fit was obtained with BW and one or more ultrasound measurement with the 7.5-MHz probe.

The relationship of ultrasound measurements taken from two different anatomical regions to carcass traits and chemical composition of the carcass in Karayaka lambs

“…Emenheiser et al (27) similarly reported that UFT and carcass fat amount variations were greater than those of other traits. In another study on sheep and male lambs, Silva et al (20) reported that fat thickness, which had a variation of 62%, had the greatest variation value.…”

“…They also reported that carcass fat amount could be determined with only the UFT measurement (R 2 = 69%-70%), and that the carcass bone amount might be estimated only with live weight (R 2 = 52%-81%). Silva et al (20) remarked that muscle amount estimation (R 2 = 99%) may be made with live weight in conjunction with UFT and ULD values taken from the 12-13T region, and that live weight and UFT may be used to predict total fat amount (R 2 = 98%). There is no statistically significant regression equation for predicting the chemical composition of the carcass from the USF, UFT, ULD, ULW, and ULA values taken from 12-13T and 3-4L in this study.…”

Desempenho e características da carcaça de cordeiros alimentados com bagaço de caju

“…A utilização da ultrassonografia tem se mostrado uma téc-nica eficiente para avalivar a gordura subcutânea in vivo, a deposição muscular; bem como estimar a qualidade e a composição da carcaça (Silva et al, 2003); permitindo prever o momento ideal do abate (Teixeira et al, 2008). Estudos em caprinos (Teixeira et al, 2008), ovinos (Silva et al, 2006, Teixeira et al, 2006, suínos (Dutra Jr. et al, 2001) e bovinos (Prado et al, 2004) têm demonstrado uma correlação altamente significativa entre as medidas realizadas por meio da ultrassonografia e as realizadas na carcaça, tornando-se uma técnica de elevada precisão para predizer a composição da carcaça.…”

Imaging technologies to study the composition of live pigs: A review

“…The US has also been used to study intramuscular fat in live pigs (Newcom et al, 2002) and in other species, such in cattle to study the repeatability and accuracy of US in measuring backfat (Brethour, 1992) and sheep to study estimation of sheep carcass composition using real-time ultrasound (Silva et al, 2006). It has been similarly used, either in vivo or post mortem, to estimate raw meat quality characteristics, mainly intramuscular fat, with the highest reported R 2 of 0.92 in pork (Newcom et al, 2002).…”