100 Low Moisture, Cooked Molasses Blocks for Limit-Creep: A Method for Supplementing Trace Minerals to Pre-Weaned Beef Calves

• Published in: Journal of animal science 2018-03, Vol.96 (suppl_1), p.51-52
• Main Authors: Ranches, J, Drouillard, J S, Silva, L D, Zylberlicht, G, Moreira, A D, Heldt, J S, Arthington, J D
• Format: Article
• Language: English
• ISSN: 0021-8812; 1525-3163
• DOI: 10.1093/jas/sky027.097

Abstract Two studies were conducted at UF/IFAS, Range Cattle Research and Education Center to evaluate, (1) preferential intake of low moisture, cooked molasses blocks (LMB) differing in formulation only by source of Cu, Zn, and Mn, and (2) pre-weaning performance of calves consuming LMB with and without trace mineral fortification. In Exp. 1, 18 calves were placed in 6 bahiagrass paddocks (Paspalum notatum; n = 3 /paddock) for 6 wk. Calves were provided concentrate daily at 2% of BW in addition to simultaneous and continuous access to 3 separate LMB fortified with differing sources of Cu, Zn, and Mn (hydroxychloride, sulfate, or organic proteinate). Preferential intake was estimated by the disappearance of each LMB. Blocks formulated with hydroxychloride sources of Cu, Zn, and Mn had the greatest disappearance when compared to sulfate (P = 0.03) and organic proteinate (P = 0.005) sources. There were no differences (P = 0.58) in disappearance rate between sulfate and organic proteinate sources (340, 277, and 254 g/calf daily for hydroxychloride, sulfate, and organic sources, respectively; SEM = 45.8). As a percentage of total LMB consumption, calves consumed 39, 32, and 29% of the formulations containing hydroxychloride, sulfate, and organic proteinate, respectively. In Exp. 2, 24 cow-calf pairs were placed in 12 bahiagrass pastures (n = 2 /pasture). Calves were provided supplement in cow exclusion areas for 84 d. Treatments consisted of 2 LMB formulations; (1) no added minerals, Control, or (2) 550, 1,650, and 2,200 mg/kg of Cu, Zn, and Mn from hydroxychloride sources; Fortified. Intake was estimated by the disappearance of LMB. Intake was greater (P < 0.05) for Control vs. Fortified (395 vs 272 g/calf daily; SEM = 85.5). Despite differences in intake, calf ADG did not differ (0.88 and 0.88 kg/d for Control and Fortified, respectively; SEM = 0.111; P = 0.97). Liver biopsy samples were collected from calves at the end of study. Calves consuming Fortified LMB had greater (P < 0.001) liver Co, Cu, Mn, Se, and Zn concentrations compared to Control. Additionally, liver Se concentrations were in the deficiency range (< 0.60 mg/kg DM) for calves consuming Control, but not Fortified LMB (0.49 vs 1.19 mg/kg DM; SEM = 0.150). Weaned calves display a preference for consumption of LMB fortified with hydroxychloride vs. sulfate or organic sources of Cu, Zn, and Mn. Pre-weaning supplementation of mineral-fortified LMB is an efficient strategy to improve the trace miner