348 Effects of supplemental copper zinc and manganese source on growth performance and carcass characteristics of finishing beef steers

摘要

The objective of this study was to determine if different sources and levels of supplemental copper (Cu), zinc (Zn), and manganese (Mn) affect growth performance, health and carcass characteristics of finishing beef steers. A large pen, commercial feedlot in OK utilized 1,707 crossbred steers (297 ± 5 kg) randomized across 8 pens/treatment. Supplemental trace mineral treatments consisted of: Control (CON) = CuSO4 plus Availa® Cu (10.6 ppm), ZnSO4 plus Availa Zn (37.8 ppm), and MnSO4 plus Availa Mn (25.5 ppm); Combination (COMBO) = basic Cu chloride (IntelliBond® C; 10 ppm), ZnSO4 plus Zn methionine (ZINPRO® 120; 90 ppm), and MnSO4 plus Mn hydroxychloride (IntelliBond M; 20 ppm); or Hydroxy (HYD) = basic Cu chloride (IntelliBond C; 10 ppm), Zn hydroxychloride (IntelliBond Z; 90 ppm), and MnSO4 plus Mn hydroxychloride (IntelliBond M; 20 ppm). Statistical analysis was performed using SAS with pen as the experimental unit and pre-planned orthogonal contrasts to separate means. Contrasts were: CON vs. COMBO and HYD (level) and COMBO vs. HYD (source). Supplemental trace mineral source or level did not affect final BW (P ≥ 0.34), ADG (P ≥ 0.36), DMI (P ≥ 0.36), feed efficiency (P ≥ 0.30), morbidity (P ≥ 0.28), total treatment days (P ≥ 0.43), or mortality (P ≥ 0.33) (Table 1). Additionally, trace mineral source or level did not affect HCW (P ≥ 0.78), DP (P ≥ 0.85), or backfat thickness (P ≥ 0.32) (Table 2). Increased level of trace mineral tended (P = 0.13) to increase marbling score. There was tendency for COMBO to have a larger loin muscle area (P = 0.14) and lower yield grade (P = 0.10) than HYD. Feeding a lower level of sulfates and amino acid complexes resulted in similar performance to higher trace mineral levels. Providing 100% Zn from Zn hydroxychloride resulted in an economic benefit while maintaining similar performance and carcass characteristics as feeding a combination of ZnSO4 and Zn methionine.