ARS | Publication request: Nutrient Management Considerations for Cow-Calf Operations

Submitted to: National Cattlemen's Convention and Trade Show
Publication Type: Proceedings
Publication Acceptance Date: January 11, 2002
Publication Date: January 17, 2002

Interpretive Summary: The effects of beef cattle operations on the environment is a growing concern among many groups. Because of this concern, many "common" practices may need to be revised and producers may be required to balance production efficiency with real and perceived environmental concerns. This manuscript attempted to review factors that affect whole farm nutrient balance on typical cow-calf operations in Florida and provide possible solutions to these challenges. Under ideal sustainable conditions, the whole-farm nutrient (N, P, and K) balances (input minus output) approach zero. Nutrient inputs to cow-calf operations include fertilizers, feeds, new animals, N-fixation, irrigation, and drift. Nutrient outputs include calves, cull cows/bulls, runoff, percolation, dust, gaseous losses, and hay or manure removed from the location. Imbalances between nutrient inputs and "managed" outputs result in losses of nutrients to the environment and(or) additions to soil storage. Nutrient management on cow-calf operations can be improved by using the following rules: 1) minimize the import of feeds, 2) minimize the import of fertilizers, 3) maximize recovery of nutrients in forages, 4) maximize recovery of nutrients in livestock, 5) minimize erosion and runoff, 6) become knowledgeable about critical issues, 7) don't make someone else's environmental problem yours, 8) develop a ranch conservation plan, 9) train employees, and 10) analyze costs and evaluate options to minimize losses. In order to meet some future environmental regulations, producers will need to balance these factors to determine the optimum management from an economical, liability, and ecological stand point.

Technical Abstract: The effects of beef cattle operations on the environment is a growing concern among many groups. This manuscript attempts to review factors that affect whole farm nutrient balance on typical cow-calf operations and provide possible solutions to these challenges. Simply defined, nutrient balances are nutrient inputs minus nutrient outputs. Under ideal sustainable conditions, the whole-farm nutrient balance approaches zero. Nutrient inputs to cow-calf operations include fertilizers, feeds, new animals, N-fixation, irrigation, and drift, whereas, outputs include calves, cull cows, runoff, percolation, dust, gaseous losses, and hay removed from the location. Imbalances between inputs and "managed" outputs result in losses of nutrients to the environment and(or) additions to soil storage. Although 60% or more of urinary N is volatilized as ammonia, the net loss is only 10 to 20% of urinary N excreted. Cattle do not redistribute nutrients evenly across pastures. Nutrients concentrate in areas where animals congregate. Use of buffer strips can decrease runoff of N and P by 94%. Only 1 to 10% of fertilizer nutrients applied to ranches are removed in animals that leave the ranch. Thus to approach zero N, P, or K balances, a portion of the pasture must be cut for hay. The supplement fed can affect the balance of N, P and K. Protein degradability and ruminal escape methionine may be factors to consider in protein supplementation programs. By optimizing cow size and milk production to the available resources, nutrient inputs can be decreased. To meet future environmental regulations, producers will need to balance these factors to determine the optimum management from an economical, risk, and ecological stand point.