Manure Total Nitrogen Flux from Condensed Tannin Fed Beef Cattle

Abstract. A study was conducted to determine the effects of three levels of condensed tannins fed to 27 beef feed yard steers on total nitrogen (N) flux from manure. Condensed tannins were fed at rates of 0, 0.5, and 1% of the daily ration on a dry matter basis. Manure and urine were collected over two periods for 6 days each. Manure was placed in inert plastic containers and urinary output was calculated on a per animal basis, and added to the manure. Air was passed over the feces/urine mixture at a rate of 1.4 L min^-1, then through individual acid traps containing 0.2 M H₂SO₄. Headspace samples were also collected with an airtight syringe and injected into a GHG GC for analysis. Tannins fed to cattle at the 0.5 and 1.0% levels showed a 48% and 42% reduction in total N flux over the control. Thus, preliminary results indicate that condensed tannins fed to beef cattle can effectively reduce nitrogen output in confined beef animal facilities.