Different levels of protein in the first winter may affect the meat quality of Uruguayan steers finished on pastures or grain?

摘要

Sixty steers were fed during first winter with different levels and source of protein. The steers grazed on improved pastures until reached 350 kg of liveweight, assigned to a finishing period on pastures-P (n=30) or grain-G (n=30). Treatments were: T1) P13-P: diet with 13% of crude protein (PC) and fattened on P; T2) P13-G: 13% PC, fattened on G; T3) P15-P: 15% PC fattened on P; T4) P15-G: 15% PC fattened on G; T5) P17-P: 17% PC fattened on P; T6) P17-G: 17% PC fattened on G; T7) U100-P: 15% PC, using urea 0.5% of diet, fattened on P, T8) U100-G: 15% PC, urea 0.5% of diet fattened on G; T9) U50-P: 15% PC ureal% of diet, fattened on P, T10) U50-G:15% PC ureal% of diet fattened on G.The aim was to evaluate the effect of the combination of the diets (first winter stocking and finishing periods) on carcass and meat quality (subcutaneous fat cover-SF, meatcuts/fat ratio- C:F, color of fat-FC and meat-MC, marbling- Marb). There was a clear effect (P<0.05) of the finishing period in SF, C:F, FC and MC. Grain diets improved FC and MC, presenting higher values of SF and lower C:F ratio than grass fed animals. It was not observed any clear effect of levels and source of protein in carcass and meat quality. Comparing T1 vs. T2, steers form T1 showed differences (P<0.05) on SF and Marb. Those results suggest that the level of protein could affect the growth of the animals and their tissue composition considering the finishing diet regimes.