Bluegrass Straw in Dairy Diets to Enhance Environmental Quality

View the project final report

Commodities

• Animal Products: dairy

Practices

• Animal Production: feed/forage, feed formulation, feed rations, stockpiled forages
• Education and Training: demonstration
• Farm Business Management: budgets/cost and returns, value added
• Production Systems: agroecosystems, holistic management

Abstract. This proposal was to enhance environmental quality and economic viability of agricultural operations by using bluegrass straw to reduce phosphorus excretion of dairy cows. Agricultural operations that affect environmental quality include field burning of bluegrass straw on air quality and the potential impact of manure application to fields on surface water quality. New markets for bluegrass straw would provide an alternative to field burning of the residual straw from bluegrass seed production. Dairy rations offer a potential new use for bluegrass straw, which possesses the properties of low phosphorus and high fiber content. In addition to reducing phosphorus excretion, inclusion of bluegrass straw into dairy rations would reduce total nitrogen intake of cows and help to reduce ammonia emissions. Bluegrass straw was incorporated at levels of 0, 10, and 15% into diets of dairy cows in late lactation to determine effects on milk yield and utilization of dietary phosphorus and nitrogen. The bluegrass straw replaced alfalfa hay in the diets. The bluegrass straw only slightly reduced feed cost ($0.05 and $0.20 per cow per day at the 10% and 20% inclusion rate) but nitrogen excretion was reduced by 46 and 69 grams per day, respectively, by the bluegrass straw. A second study was done in which growing heifers were fed up to 20% bluegrass straw. Growth was not significantly affected by the bluegrass straw,

1. Determine the level at which bluegrass straw can be added to diets of high-producing lactating cows without adversely affecting milk production and composition. Calculate a phosphorus balance with cows fed bluegrass straw and determine the reduction in phosphorus excretion that results. Determine the level at which bluegrass straw can be included in diets of growing dairy heifers. Estimate the impact on feed costs and excretion of nitrogen of phosphorus when bluegrass straw is incorporated into dairy diets.