205 Effect of supplemental trace mineral source on performance, health, and carcass characteristics in finishing beef steers

Abstract

Abstract Crossbred beef steers (n = 2,420; 357 ± 16 kg BW) were used to evaluate the effects of supplemental trace mineral sources on the performance and carcass characteristics on feedlot cattle. Steers were housed in 20 pens (120–125 steers per pen) with 10 pens per treatment. Supplemental trace mineral treatments (100% DM) consisted of: control: 8.3 mg/kg of Cu (100% CuSO4), 83.4 mg/kg of Zn (64.1% ZnSO4/35.9% Zn amino acid complex), and 28.7 mg/kg of Mn (100% MnSO4); hydroxy: 8.3 mg/kg of Cu (100% basic Cu chloride), 82.9 mg/kg of Zn (100% Zn hydroxychloride), and 19.3 mg/kg of Mn (100% Mn hydroxychloride). Steers were fed trace mineral treatments for 158 d and harvested at a commercial abattoir. Data were analyzed as a randomized complete block design with pen as the experimental unit. There were no differences between treatments in DMI, ADG, feed:gain, final BW, or mortality (P ≥ 0.38); however, morbidity tended (P = 0.06) to be greater for hydroxy than control (3.44 or 2.20%, respectively). Hot carcass weight, dressing percentage, marbling score, and longissimus muscle area were unaffected (P ≥ 0.28) by treatment, though backfat tended (P = 0.07) to be greater for hydroxy compared to control (1.55 or 1.51 cm, respectively). Distributions of quality grades were not different (P ≥ 0.14) with the exception of increased (P = 0.01) Prime carcasses in control compared to hydroxy (2.57 or 1.18%, respectively). Distributions of yield grades 2, 3, and 4 were not different (P ≥ 0.17) between treatments, though percentage of carcasses assigned 1 was reduced (P = 0.01) and 5 was increased (P = 0.05) in hydroxy compared to control. These data indicate steers fed 100% hydroxychloride trace minerals perform similiarly to steers fed CuSO4, MnSO4, and a ZnSO4/Zn amino acid complex combination.