Evaluator effect on the ultrasound measurement of subcutaneous fat deposition and loin eye area from weaning to slaughter lambs

Abstract

Background and Aim: Ultrasound is a non-invasive technique that enables animal evaluation and body condition classification of animals. Although it is not difficult to obtain an image, the analysis of this image can influence results quality. This study aimed to evaluate the repeatability and reproducibility of the technician trained in image interpretation obtained using different ultrasound frequencies. Materials and Methods: Ninety-six lambs were used, ranging in weight from 15 to 40 kg. The images were captured using a linear probe of 13 cm, with a 3.5 megahertz (MHz) frequency and an acoustic couplant aid "standoff" or using a multifrequency transducer (6 and 8 MHz), on B mode, with a linear probe and 8.0 MHz frequency. All measurements were performed by the same technician, on the left side, between the 12th and 13th rib. Five different evaluators, at two different times, with aid of Image J software measured the loin eye area (LEA; only for images obtained with 3.5 MHz), Longissimus thoracis et lumborum depth (DLM), subcutaneous fat thickness (SFT), subcutaneous fat thickness plus skin (SFST), and skin thickness (ST). Results: For LEA, DLM, SFT, SFST, and ST, variation was observed (p<0.01) between evaluators; however, there was no difference (p>0.05) between the 2 times of evaluation. Images measurements obtained with a frequency of 8.0 MHz had better repeatability indices and reproducibility indices. Accordingly, the identity test demonstrated that measurements performed on images obtained using 3.5 or 8.0 MHz were not equivalent. Conclusion: Ultrasound image measurements obtained using an 8.0 MHz frequency were more accurate and precise. It is important to use only one evaluator or providing the simultaneous training for all evaluators.

Effect of partially replacing corn with sugar cane molasses on blood parameters and composition of the M. longissimus thoracis of growing pigs

“…Each sample was photographed over a blank surface, and a ruler was placed over the meat cut to obtain the pixel-to-mm ratio for further image analysis (15) . Eye muscle area was determined via image processing using ImageJ® software (NIH, Maryland, USA) and Bio7® editor (https://bio7.org/ ) (16,17) . Subsequently, six ribeye steaks were fabricated from each LT.…”

Modelling and predicting fat deposition rates in various South African sheep crosses using ultrasound technology

“…While numerous studies have focused on predicting carcass composition using ultrasound scans of various traits, including fat depth (Fernández et al, 1998 ; Teixeira et al, 2006 ; Cadavez et al, 2007 ; Orman et al, 2008 ; Thériault et al, 2009 ; Akdag et al, 2015 ; Silva, 2017 ; Dias et al, 2020 ; Vargas et al, 2021 ), models to predict fat cover per se are lacking. Van Der Merwe et al ( 2022 ) modelled the fat deposition of various South African sheep breeds and then developed predictive models using age or live weight as inputs, but only focused on pure breeds.…”