Estimation of longissimus muscle area by real-time ultrasound measurements in Charolais breed

Abstract

Authors’ aim was to test Falco100 (Pie Medical, 3.5 MHz head) ultrasound machine for measuring the area of musculus longissimus dorsi in cattle. Research was carried out in 2003 on a Hungarian farm, with Charolais bulls (B, n=17, age: 545 days, live weight: 400.7 kg) and heifers (H, n=6, age: 540 days, live weight: 358.1 kg). Animals were kept in a barn with a paddock, in small groups, fed on corn silage, hay (ad libitum) and concentrate (limited). Applying Falco100 machine, depth of skin, subcutaneous fat thickness, and longissimus muscle thickness were measured between 12-13rd ribs. From these data and live weight the software of the machine calculates longissimus muscle area automatically, using regression equations. Results of ultrasonic measurements did not differ significantly between sexes (P>0.05): skin depth, cm B=0.39; H=0.43; subcutaneous fat thickness, cm B=0.48; H=0.54; longissimus muscle thickness, cm B=6.94; H=6.47; longissimus muscle area, cm: B=86.42; H=80.24. Ultrasound measurements correlated positively with live weight (r=0.23-0.60), but correlation coefficients differed between sexes in case of fat thickness (B: r=0.34, H: r=0.73), longissimus muscle thickness (B: r=0.40, H: r=0.23), and longissimus muscle area (B: r=0.41, H: r=0.23). According to their results, Falco 100 with 3.7 MHz transducer is suitable for measuring longissimus muscle area, but for determination of differences between sexes more measurements are neccessary.