Performance and Tissue Mineral Composition of Ruminants Fed Cage Layer Manure in Combination with Monensin2

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Abstract
Twenty-four steers, initially averaging 256 kg, were used in a 2 × 3 factorial arrangement of treatments to determine the effect of monensin (22 g/metric ton) in combination with three levels (0, 12.5 and 25.0%) of cage layer manure as a replacement for soybean meal in finishing diets. Average daily gains for 0, 12.5 and 25.0% cage layer manure with and without monensin were: .99, 1.04, .90 kg and 1.03, .86, 1.01 kilograms. Feed intake and feed conversion were not affected by any treatment. Ruminal propionic acid concentration averaged 50.5, 42.8, 36.0 moles/100g with monensin and 37.3, 30.5, 26.6 moles/100g without monensin (P<.01) for 0, 12.5, 25.0% cage layer manure, respectively. Carcass evaluation revealed no significant differences in quality or yield grades, dressing percentage, or flavor and juiciness of broiled steaks. Addition of cage layer manure increased Ca (P<.01) in muscle, Cu (P<.01) in liver and Mg (P<.01) and P (P<.05) in kidney, but decreased (P<.05) Fe in kidney. Arsenic in kidney and muscle increased (P<.05) when cage layer manure was fed, but levels of As, Pb, Cd and Hg did not accumulate to a level that may be harmful to ruminants. A metabolism study was performed in a 2 × 2 factorial arrangement of treatments to evaluate the effect of 33 g monensin/metric ton on nitrogen utilization in 32 wether lambs fed diets containing cage layer manure or soybean meal as sources of nitrogen When compared to the controls, monensin decreased (P<.01) fecal nitrogen excretion (9.6 vs 9.0 g/head daily), and increased (P<.01) digestibility of nitrogen (45.3 vs 48.4%) and urinary excretion (6.8 vs 7.1 g/head daily). Lambs fed soybean meal had a higher (P<.01) nitrogen digestibility (40.9 vs 52.9%) than did cage layer manure-fed lambs. Nitrogen retention was not affected by treatment. Copyright © 1980. American Society of Animal Science . Copyright 1980 by American Society of Animal Science.