392 Effects of a vitamin and mineral bolus on heifer feedlot performance, feeding behavior and carcass characteristics

Abstract

Abstract Crossbred beef heifers (n = 23; initial BW= 370.0 ± 11.5 kg) housed at the Beef Cattle Research Complex (BCRC) in Fargo, ND were used to evaluate effects of a vitamin and mineral bolus on feedlot performance, feeding behavior, carcass characteristics, and liver mineral concentrations. Heifers were assigned to one of two treatments: 1) received no supplemental mineral or vitamin (CON, n = 12), or 2) received two mineral and vitamin boluses on d 0 (Ca, Mg, Na, Cu, I, Mn, Se, Zn, Co, Vitamin A, Vitamin D3, and Vitamin E; Reloader 250, Cargill Inc., Minneapolis, MN; MIN, n = 11). Heifers were fed a TMR (16.05% CP, 1.44 Mcal NEg) with no added vitamin or mineral supplement. Feed intake, number and time of visits were recorded for each heifer using the Insentec feeding system (Hokofarm Group B.V., the Netherlands) over the 150 d feeding period. Liver biopsies were conducted on heifers on d 0, 69, and 134 of the feeding period to measure mineral concentrations. Carcass characteristics were determined. Data were analyzed in SAS using the GLM procedure with heifer as the experimental unit. Final BW, ADG, DMI, G:F, and carcass characteristics were similar among treatments (P > 0.19). Control heifers visited feeders more but spent less time per visit and ate less per visit compared with MIN heifers (P < 0.03). No differences (P > 0.31) were observed among treatments in d 0 or 134 liver mineral concentrations. At d 69, Co was lower (P = 0.01) in CON heifers compared to MIN heifers; however, Se, Fe, Cu, Zn, Mo, and Mn were not different among treatments (P > 0.34). In this experiment the vitamin and mineral bolus evaluated failed to increase liver mineral concentrations over the finishing period or impact heifer performance and carcass characteristics.