Long-Term Strategies for Reducing Excess N on Farms
- Develop a crop and manure nutrient management plan. Cornell Cropware software can be used in New York State to meet CAFO requirements while matching manure and commercial fertilizer nutrients with crop requirements to produce crop yields up to soil potential (and management level) on each farm.
- Improve silo management. Silo capacity and management can play a significant role in decreasing nutrient excretion. Most dairy farms have varying soil types that are best suited for different crops from a crop production and environmental management standpoint. The storage system must be able to handle each crop type individually (e.g., corn silage, grass silage, alfalfa silage, and different qualities of each). This allows the nutritionist to better match protein and carbohydrate sources with specific animal groups.
- Manage forage inventory to avoid feed shortages. Proper ration planning and inventory management decrease farm nutrient loading. This is because a forage deficiency requires additional purchased feed and automatically increases excretion from purchased feeds. The CNCPS predicts requirements for each ration ingredient (by group and the entire herd), and can be used to allocate, and manage, forage inventory.
- Match cows/crops/soils. Alfalfa and corn are not always the best choices for dairy producers due to soil constraints. The farm’s manager(s), nutritionist, and field crops consultant must work together to determine the best mix of crops to grow, and how they can be fed, allowing for production goals (crop and animal) to be met while minimizing nutrient excretion. Future CU NMPS versions will predict feed production with alternative crop rotations, and management, to minimize farm-gate imported nutrients and the spreadable acres required.
- Increase the amount of homegrown feeds in the ration. Increasing the amount of homegrown feeds in the ration decreases the amount of purchased nutrients. To accomplish this, homegrown feeds must be high quality to achieve optimal rumen fermentation for maintained (or improved) production and animal health.
- Impact of Forage quality. To increase the amount of forages in the rations, forage quality must be high. Maximum intake from forages can be expected when alfalfa is <40% NDF, grasses are <55% NDF, and corn silage is 40-45% NDF (Tylutki and Fox, 2000). A cow is limited in forage NDF intake to 1 to 1.1% of bodyweight (Mertens, 1994). As an example, a 1400 pound cow at 1.1% NDF capacity can consume 28 pounds of dry matter from grass at 55% NDF but only 24 pounds at 65% NDF. This four pound difference results in either increased purchased feeds and/or lower performance. In either case, purchased nutrient use efficiency is lower.
- Impact of Grains. Homegrown grains and protein sources decrease the amount of purchased nutrients. Many dairy farms do not have an adequate land base to produce their own grain; therefore, they should maximize forage quality and choose purchased concentrates that accurately supplement their forages.