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Effect of Pasture or Maize Silage Feeding on the Nutritional Value of BeefThe objective of this study was to evaluate the nutritional value of beef from different production systems. The study was conducted with Hereford bulls on organic and conventional farms. On the organic farm, fattening was mainly based on roughages, including pasture forage in the summer season, when the end of fattening occurred. On the conventional farm the bulls were fed maize silage and concentrate. On both farms, the animals were aged 7-9 months at the beginning of fattening. The bulls were fattened to a final body weight of 550-600 kg. Samples of longissimus thoracis muscle were collected from half-carcasses of slaughtered bulls originating from each farm to analyse fat content, fatty acid profile, and content of selected minerals and vitamin E. Muscle samples were additionally analysed for the concentration of thiobarbituric acid-reactive substances 3 and 7 days after slaughter. Analyses showed a lower fat content in longissimus thoracis muscle of bulls from the pasture feeding system. The fatty acid profile was also characterized by a lower content of C 14:0, and a higher content of polyunsaturated fatty acids (PUFA), including C18:3 n-3, conjugated linoleic acid, C 20:5 n-3, and C 22:5 n-3, as well as by a lower ratio of n-6/n-3 PUFA. The total content of monounsaturated fatty acids was significantly higher in animals fed maize silage and feed concentrate. In turn, the muscle of pasture fed animals had higher levels of Na, Zn and Fe as well as of vitamin E.

The polyunsaturated fatty acid (PUFA) content of M. longissimus thoracis was determined in Hereford, Limousine and Charolais fattening bulls fed concentrate and maize or grass silage as the basie feed for 7 months. The PUFA n-3 content was higher in Charolaise bulls than in other breeds, and was significantly higher in animals fed on grass than on maize silage. The ratio of PUFA n-6/n-3 was the most advantageous in Hereford bulls.

The objective of the experiment was to study the nutritive value and meat quality aspects of domestic cattle (Bos taurus), zubron (Bos taurus × Bison bonasus) and European bison (Bison bonasus) meat. The bulls and zubrons were fattened to 600-650 kg of body weight using the same feeding regimen. The European bison meat was from selective shooting of males. The meat was analysed for chemical composition, fatty acid composition, meat quality characteristics and thiobarbituric acid reactive substance (TBARS) value. Compared to beef, zubron and European bison meat had a lower content of crude fat, crude ash and a higher moisture content. The meat of the zubrons and European bison showed a lower content of saturated fatty acids and a higher content of polyunsaturated fatty acids compared to beef. The shear force of meat was highest for European bison meat and lowest for beef. Higher a* and b* colour parameters were established in European bison and zubron meat. The highest TBARS value was found in beef.

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