Ultrasound scanning for quality assessment of longissimus dorsi muscle in cattle: Measuring meat quality in live animals

The meat industry is observing an increase in the population of purebred animals from the finest meat breeds globally, due to the introduction of innovative solutions in animal husbandry, feeding practices, breeding techniques, and overall management [1]. Ultrasound can be added in breeding programs to select animals with the potential to pass on superior meat qualities [2]. Key indicators of good quality include fat thickness, the area of the longissimus dorsi muscle, hide thickness, the percentage of intramuscular fat, and the marbling score [3]. The aim of this study was to determine the relationship between daily body weight and indicators of quality meat using ultrasound imaging. During the study, a total of 603 cattle scans were performed. Daily weight gain was calculated by deriving the average of age and weight. Ultrasound scan was performed using MyLabOneVET ultrasound equipment (Esaote, Germany). During the scan, the sensor was pressed deep into the muscle for a few seconds until the image on the screen was smooth and consistent. Different structures are visible during the examination: subcutaneous fat, transverse section of the long back muscle, and fat layer near the rib cage. After the examination, the created images are saved. After the examination, the stored images are evaluated and adipose tissue measurements are performed in the scanner, then the muscle area and the fat layer near the ribs are evaluated in this way. The data were calculated using installed formulas, according to which it is possible to accurately calculate the yield percentage while the animal is still alive. The measurement data were coded and compiled using an Excel (MsOffice, USA) calculator. To calculate the relationship between the outcome variables, the Pearson correlation test was performed, and the correlation coefficient R was calculated, which does not depend on the measurement units of the variables. This study was conducted in six different farms in Lithuania. Before each ultrasound examination, the cattle were weighed, and their heads were fixed accurate scanning. After analyzing the collected data, it was found that the daily weight of the animals varied from 0.51 kg/d up to 2.7 kg/d, on average 1.41 kg/d. A weak positive correlation (r = 0.372) was found in correlation tests between daily body weight and long back muscle area, P < 0.01. The study also analyzed the relationship between yield grade and daily weight gain. It was found that there was no significant correlation between these two parameters. A similar trend was observed when analyzing the relationship between daily body weight and intermuscular fat percentage (IMF): the correlation was very weak, but positive. Analysis of the data on fat thickness and daily weight demonstrated that there was no correlation between these parameters. This shows that the daily weight does not have a significant effect on the thickness of subcutaneous fat. However, a weak positive correlation (r = 0.383) was found between daily body weight and the thickness of the longus back muscle, P < 0.01. The results of this study do not prove the benefits of ultrasound scanning. The study found only a weak relationship between the measured parameters. The study has several methodological limitations, so further research is needed to accurately assess the benefits of ultrasound scanning.