Estimation in vivo of the body and carcass chemical composition of growing lambs by real-time ultrasonography1

Abstract

The relationship between ultrasound measurements and empty body and carcass chemical composition was investigated. A 500-V real-time ultrasound with a 7.5-MHz probe combined with image analysis was used to make in vivo measurements to predict the empty body and carcass chemical composition of 31 female lambs of two genotypes, ranging in BW from 18.2 to 48.9 kg. Eleven ultrasound measurements of s.c. fat, muscle, and tissue depth were taken at four different sites (over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, at the 3rd sternebra of the sternum, and over the 11th rib, 16 cm from the dorsal midline). The single best predictor of empty body fat quantity and energy value was the s.c. fat depth over the 13th thoracic vertebra (r(2) = 0.904 and 0.912; P <0.01, respectively). Body weight was used with ultrasound measurements in multiple regression equations to establish the best independent variables combination for predicting chemical composition. Results showed that BW and two of the three ultrasound measurements (s.c. fat depth over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, and tissue depth over the 11th rib, 16 cm from the dorsal midline), explained 94.7 to 98.7% (P < 0.01) of the quantity of water and fat and the energy value variation in the empty body and carcass. Body weight per se was the best predictor of the quantity of protein, accounting for 97.5 and 96.8% (P < 0.01) of the variation observed in the empty body and carcass, respectively. The results of this study suggest that BW and some ultrasound measurements combined with image analysis, particularly subcutaneous fat depth over the 13th thoracic vertebra, allow accurate prediction of empty body and carcass chemical composition in lambs.

In vivo estimation of lamb carcass composition by real-time ultrasonography

“…This variable accounted for 63-96% of the variation in carcass tissue weights. These results agree with those found by Delfa et al (1996), Fernández et al (1998), Hopkins (1990), Mendizabal et al (2003) and Silva et al (2005) and Teixeira and Delfa (1997). On the other hand, Ramsey, Kirton, Hogg, and Dobbie (1991) were of the opinion that the improvements in accuracy of prediction due to live weight were not sufficient to warrant the use of this variable in multiple regression equations, which is not in agreement with the results obtained in the present work.…”

“…The low correlations found can be explained by the light lambs we have worked with which have a very low subcutaneous fat layer and this limits the potential of ultrasound to provide accurate measures as well as the high range in fat depths on the carcass (C 12-13 and C 3-4 measurements) than the ultrasonic fat measurements taken on the live animal (Table 1). Our coefficients are lower than those found by Silva et al (2005) and this can be explained by the different ultrasonic measurement procedures. We did not shear and clip the wool as this not possible in a commercial slaughter house.…”

“…Recently, working with the same breed of the present study Cadavez, Teixeira, Delfa, and Rodrigues (2000) and Cadavez et al (2001) have been evaluating of ultrasonic measurements of fat thickness to estimate the carcass composition. Silva, Gomes, Dias-da-Silva, Gil, and Azevedo (2005) working with Île de France and the native Portuguese breed Churra da Terra Quente found that body chemical composition of growing lambs can be predicted by the body weight and real time ultrasonography measurements associated with the image analysis. So the objective of this study was to evaluate the accuracy of the ultrasound to measure fat thickness in live lambs and predict the carcass composition and to contribute as to find a system that can assess the carcass composition easily and accurately, without depreciation of the product and improve the carcass classification giving more information to consumers.…”

Effects of increasing dietary concentrations of fish oil on lamb performance, ruminal fermentation, and leptin gene expression in perirenal fat

“…The hot carcass yield was obtained following slaughter of the lambs on day 56 and the ultrasound back fat was assessed one day before slaughter (Silva et al, 2005 Samples from the perirenal adipose deposits were removed via biopsy techniques within 4 min after slaughter to determine expression of leptin mRNA (Kumar et al, 1998) and total RNA was isolated from the fat by homogenization of tissue (Tissue-Tearor TM , Daigger ® , Daigger & Company Inc.) in Tri Reagent R (Sigma Chemical Co. Ltd.). Total RNA was used for reverse transcription and Leptin mRNA expression was quantified with realtime polymerase chain reaction (PCR) using the forward and reverse primers, 5'-ACAACACACGATGGAAGCAT-3' and 5'-ACCCCAAAAAGCCTGGAAAA-3, and total number of cDNA copies was estimated as described by Tricarico et al (2002).…”

Padrão de deposição de tecidos protéicos e gordura em cordeiros abatidos precocemente e sua mensuração utilizando a ultra-sonografia

“…O local a ser efetuada as medidas foi estudada por Fernandes et al,1998, encontrando a melhor localização para medida de espessura de gordura entre a 12ª e 13ª costela (r2=0.92,P<0.001), em borregos da raça Manchego; Silva et al, 2005, também encontrou na região da 13ª costela o melhor preditor de gordura subcutânea. Trabalhos mais recentes como de Teixeira et al, 2006, utilizaram para espessura de gordura entre a 12ª e 13ª costela e entre a 3ª e 4ª vértebra lombar na raça Churra Galega Bragançana e Ripoll et al, 2009, entre 10ª e 12ª costela, 12ª e 13ª costela, 1ª e 2ª vértebra lombar e 3ª e 4ª vértebra lombar, avaliando medidas de músculos e gordura na raça Tenasco.…”