Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/21/2001
Publication Date: N/A
Technical Abstract: Plant breeding and biotechnology efforts are underway in the U.S. and abroad to develop alfalfa and other forages with modest amounts of condense d tannins. Tannins bind to proteins, potentially altering N availability in forages during ensiling, ruminal digestion, and soil mineralization. We used a whole-farm dairy-forage simulation model (DAFOSYM) to predict the effect of growing and feeding an alfalfa with 1 to 2% tannin on a dair farm in southern Wisconsin with 100 cows, 85 heifers, and 100 ha of silt loam soil. Alfalfa silage and corn silage were produced and fed in ratios of 2:1 or 1:2. Crop yields were similar when normal or tannin-containing alfalfa were grown. Feeding tannin-containing alfalfa reduced farm profitability by $9,500 to $15,600 per year. Benefits were greatest in alfalfa-dominant production systems. Feeding tannin-containing alfalfa shifted grain supplementation from soybeans to corn, reducing the need for off-site production of potentially erosive and nitrate leaky row-crops by about 60%. Our current research is aimed at identifying optimal tannin concentrations and management practices for enhancing protein and N use on dairy farms.