Twenty-four Holstein steers and 23 Holstein bulls (initial body weight= 252± 3.5 kg and age= 187± 7.5 d) were randomly allocated to 4 treatments arranged in a 2 × 2 factorial design with gender (bulls vs steers) and vitamin A supplementation (either restricted at 1.3 ×1000 IU/kg, VAR, or supplemented at 4.6 × 1000 IU/kg, CTR) to evaluate the effect of vitamin A restriction on performance, carcass and meat quality traits of Holstein steers and bulls. Intramuscular fat was less (Pb0.01) in bulls than in steers, and tended (P= 0.09) to be greater in VAR than in CTR animals. Oxidative stability tended (P= 0.09) to be greater in meat from VAR than from CTR animals at 21 d of ageing. Vitamin A restriction in Holstein bulls does not achieve the same intramuscular fat levels obtained with castration.
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4. Conclusions
It is concluded that vitamin A restriction cannot achieveintramuscular fat levels found in castrated bulls. Beef from vitamin A restricted animals showed lower lipid oxidation and improved visual appearance at the end of shelf life. In addition, meat of VAR animals has greater sensorial juiciness, and tenderness than meat of animals fed regular vitamin A concentrations