The effects of breed, grazing system and concentrate supplementation on the fatty acid profile of the musculus longissimus dorsi and the kidney fat of steers

The study is aimed at determining the effect of breed (German Simmental vs. German Holstein), grazing system (continuous grazing system [CGS] vs. rotational grazing system [RGS]) and concentrate supplementation (level and type of concentrate) on the fatty acid profile of longissimus muscle and kidney fat of steers. The trial involved four phases: in P1 all animals remained indoors; in P2 and P4 they were allocated on CGS or RGS; during P3 one group remained outdoors, the other indoors. In P1 and P3 the steers were offered grass silage and concentrate. In P3 the indoors group received a supplement with a medium or low-concentrate level. For the last 28 days of P4 the steers were offered a concentrate type with 4.9% linseed oil or with 1.0% rapeseed oil. CGS-pasture resulted in higher fatty acid values than RGS-pasture; linseed-oil concentrate resulted in higher ALA, Sn-3 and lower LA, Sn-6 than rapeseed-oil concentrate. German Simmental breed had lower IMF-content and higher Sn-3, Sn-6, n-6/n-3 ratio and PUFA/SFA ratio in longissimus dorsi and kidney fat than German Holstein breed. The proportion of CLA was higher in German Holstein breed than in German Simmental breed (0.56 vs. 0.50 g/100 g FAME). RGS group showed lower ALA and higher n-6/n-3 in longissimus dorsi and kidney fat than CGS-group. Neither the level nor the type of concentrate affected the LD and kidney fat fatty acids. Healthy fatty acids levels were higher in the German Holstein breed meat. The CGS-group meat had higher contents of ALA and EPA. However, the legal requirements for human nutrition and other health related claims could not be met.