Manure Management Considerations for Expanding Dairy Herds

The requirements and considerations for manure management change as dairy operations evolve to larger herds. Changes in manure production, collection, treatment, storage, transport, and utilization are nearly always necessary as herd sizes increase. Land area requirements for nutrient utilization increase as animal numbers increase and also increase because of crop type, nutrient uptake capability, potential nutrient losses, and limits for nitrogen and phosphorus. Expansion of herd size may require obtaining, updating, or revising environmental permits from regulatory agencies. Options for reducing manure loading on existing facilities to accommodate larger herds include solids separation and off-site facilities. As herds become larger, economy of scale usually improves the ratio of costs to benefits for manure systems. Economic analysis of manure systems in Missouri showed that cost of manure management was reduced by approximately 50% per unit of milk produced as herd size increased from 100 to 500 cows. As systems for manure management become larger and more complex, engineering design inputs and requirements become more extensive. Traditional sources of engineering design and assistance, such as Cooperative Extension and Natural Resource Conservation Service, may no longer be adequate. Identification and utilization of alternate resources, such as private sector engineers, may be necessary. Retention of legal counsel who are familiar with the regulatory aspects of manure management may be advisable as herd size increases.