Manure ammonia and green house gas emissions from beef cattle fed condensed tannins

Abstract.

A study was conducted to determine the effects of three levels of condensed tannins fed to 27 beef feed yard steers on ammonia and GHG emissions from manure. Condensed tannins were fed at rates of 0, 0.5 and 1.0% on a dry matter basis. Manure and urine were collected from two periods over 6 days. Fecal and urinary output was measured on a per animal basis. Manure and urine were placed in inert plastic containers and stored separately at -4^o C until analysis. Manure was placed in 16.7 x 16.7 x 17 cm plastic chambers and urine was topically added. Samples were collected every 24 hours for 1 week, then every 48 hours for 1 week. Headspace samples were injected into a GHG GC for analysis. NH₃ concentrations were measured using a Manning Systems, Inc., ECP2 gas detector. H₂S concentrations were measured using a Jerome 631-x Hydrogen Sulfide Analyzer. Increasing amounts of tannins fed to the animals showed a 0, 51, and 57% reduction of NH₃ concentrations in the headspace, respectively. CO₂ emissions showed an increase with amount of condensed tannin fed. There was no treatment effect on N₂0 emissions. Results indicate that condensed tannins fed to beef cattle can effectively reduce gaseous NH₃ emissions from confined beef animal facilities.