Silage-concentrate finishing of bulls versus silage or fresh forage finishing of steers: Effects on fatty acids and meat tenderness

Abstract

The objective of this trial was to assess meat quality in terms of tenderness and fatty acid (FA) composition in M. longissimus dorsi and M. gluteus medius from bulls finished on ad lib silage-concentrates (SIL:CON) vs. steers fed ad lib silage (FF) or restricted silage and unrestricted grazing (RES-F). Warner-Brazler shear force value day 1 was lowest for the FF steers (p<0.05). Myofibril fragmentation index (MFI) values were similar after seven days of ageing, showing that ageing compensated for differences in meat tenderness associated with feeding programmes. Total monounsaturated FAs and 18:1c-9 levels were higher in the steer tissue (p<0.001). The SIL:CON bulls had higher polyunsaturated n-6 fatty acids and 18:2n-6 level (p<0.001). Polar lipid 18:2n-6 and n-6 levels were higher for FF than for RES-F steers, whereas the 18:3n-3 level was higher for RES-F than for FF steers (p<0.001). The n-6/n-3 ratio was lowest for the FF steers and highest for the SIL:CON bulls (p<0.001).