Slaughter and carcass characteristics, chemical composition and physical properties of longissimus lumborum muscle of heifers as related to marbling class

The experiment involved 68 heifers obtained from Polish Black-and-White Lowland dams (with no more than 50 % Holstein Friesian blood) sired by Limousin bulls. The study was arranged to determine the slaughter and carcass traits, chemical composition and physical properties of musculus longissimus lumborum (MLL) as related to the level of marbling, and to examine the correlation between some of the traits mentioned above and the culinary characteristics of meat. The results of the study show that marbling significantly affected the dressing percentage and carcass traits such as subcutaneous fat content, fat of valuable cuts and MLL area. Most of the physico-chemical properties of tested muscles, with the exception of total protein and total collagen content, were related to the level of marbling. Based on the results obtained, it appears that age at slaughter and carcass weight turned out to be poor predictors of colour lightness within all marbling classes. The same conclusion applies to the amount of total collagen in large and strong marbled muscles for shear force value. In turn, soluble collagen content for shear force could be a quite good forecaster of meat tenderness but not in highly marbled muscles. Of all tested slaughter and carcass traits, only MLL fat content seems to be appropriate to assess both: the tenderness and lightness of meat.