RELATIONSHIP BETWEEN SHORT TERM ENERGY SUPPLEMENTATION AND MEAT QUALITY OF STEERS IN ARGENTINA

摘要

IntroductionNutrition affects tissue fatty acids in cattle. The w-6: w-3 fatty acids in meat from forage finished cattle is approximately 2 (Enser et al., 2001), well below the recommended level of less than 4 (Holman, 1995). Short term maize grain supplementation in the finishing stage of beef cattle, a common practice in pastoral systems, did not affect fatty acid profile (Grigera Naon et al., 2000). On the other hand, enhanced levels of conjugated linoleic acid (CLA) in adipose tissue were found in cattle grazing pastures (French et al., 2000) , CLA concentration has also been increased by including extruded full-fat soybeans in feedlot diets (Madron et al., 2002). Full-fat soybean is an expensive commodity, produced for human consumption and recently used as a biodiesel source. Therefore, it becomes relevant to explore the strategic use of by-products of soybean harvest for feeding grazing cattle in the latter stage of fattening, taking into account that up to 60% (on a dry matter basis) of such material is made of cracked soybeans (Grigera Naon et al, 2003). However, (Grigera Naon et al., 2003) showed that using such by-products as the unique source of supplementary feeding, had some undesirable effects, such as a poorer fattening rate in comparison with those animals offered maize grain. Such supplementation also resulted in a lower CLA proportion as well as a higher w-6:w-3 in intramuscular fat (IMF) of steers .