ARS | Publication request: REQUIREMENTS FOR N AND P BY DAIRY CATTLE

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: August 4, 1999
Publication Date: N/A

Technical Abstract: The amount of fixed N released on the planet is about double the amount released prior to the industrial revolution. Most of this increase is due to use of N fertilizer in agriculture. Significant amounts, however, arise from feed production and manure handling connected with livestock operations. Nitrogen (N), along with phosphorus (P), are the two nutrients (pollutants) that must be more closely managed in order to reduce environmental damage. Nitrogen loss to the environment from dairy operations can be reduced through managing crop (feed) production to minimize need for N fertilizer and to minimize opportunity for utilizing manure nutrients. Improved diet formulations can also reduce N loss to the environment. Phosphorus levels in manure can be reduced by feeding less P. Based on survey information, dairy producers appear to be feeding about 20% more P than the National Research Council recommends. Research in our center with high producing dairy cows clearly shows that the National Research Council recommendations, based primarily on 30 year old data, are still appropriate for modern cows producing 2-3 times as much milk as cows used in the NRC data base. Reducing dietary P by 20% will reduce P content of dairy manure by 25-30%. This means that 25-30% less land will be required to recycle the manure from a herd of cows.