Abstract. Many factors affect ruminant carcass and meat quality, and among the genetic and environmental factors, feeding plays an important role in the determination of quality. In a large study, sixty-four German Holstein and German Simmental bulls were randomly allocated to either an indoor concentrate feeding system or periods of pasture feeding following by a finishing period. During this period the animals got a concentrate containing linseed to improve the meat quality for the consumer and enhance the contents of beneficial fatty acids in beef. German Simmental bulls grew faster in both feeding groups (concentrate and grass-based) compared to German Holstein bulls. Because of that significantly more days of fattening were necessary to reach the slaughter weight of 620 kg. The feeding system did not affect the carcass weights of both breeds. The results of cutting according to the regulations of the Deutsche Landwirtschaftsgesellschaft (DLG-Schnittführung für die Zerlegung der Schlachtkörper von Rind, Kalb, Schwein und Schaf) showed diet effects for different cuts. Pasture feeding significantly decreased the weights of flank, flat ribs and brisket of both breeds.

The intramuscular fat content of longissimus muscle was affected by the diet in the case of German Simmental bulls, only. The intramuscular fat content of longissimus muscle of pasture-fed German Simmental bulls was decreased to 1.5 % compared with concentrate-fed bulls (2.6 %). No diet effect was found in the intramuscular fat content of longissimus muscle of German Holstein bulls. The colour investigations of both muscles (longissimus and semitendinosus) showed that the beef produced by pasture feeding is darker. The Warner- Bratzler shear force values (WBSF) of pasture fed bulls were significantly higher compared to the concentrate fed bulls. Pasture feeding resulted in a significant increase in the concentration of n-3 fatty acids up to a factor of 2.8 in longissimus muscle of bulls compared with the concentrate feeding system.