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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Publications at this Location » Publication #308740

Title: Feed and manure use in low-N-input and high-N-input dairy cattle production systems

Author
item Powell, Joseph

Submitted to: Environmental Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2014
Publication Date: 11/3/2014
Publication URL: http://handle.nal.usda.gov/10113/62853
Citation: Powell, J.M. 2014. Feed and manure use in low-N-input and high-N-input dairy cattle production systems. Environmental Research Letters. 9(11):115004. Available: http://iopscience.iop.org/1748-9326/9/11/115004.

Interpretive Summary: The impacts of nitrogen (N) on agricultural production and the environment depend largely on levels of N applied. In Sub-Saharan Africa, fertilizers and feeds are costly, not readily available and therefore used sparingly. Conversely, in many parts of Western Europe, North America, and Oceania, fertilizers and feeds are relatively inexpensive, readily available and used abundantly in the pursuit of profitable agricultural production. A case study, dairy systems approach was used to illustrate how differences in feed and manure management in a low-N-input dairy cattle system would impact agricultural production and environmental N loss compared to a high-N-input dairy production system. The study showed that additional feed N in the low-N-input dairy production systems could be used very efficiently to produce more milk and enhance manure quality, which in turn would provide exceptional increases in the production of food, forage and biomass for soil conservation. In the high-N-input dairy production systems, small reductions in feed N would not impact milk production but would reduce excretion of urinary urea and therefore reduce N loss. Especially in the low-N-input systems, corralling dairy cattle directly in fields improves the capture of urine N and therefore manure N recycling through crops. Study results demonstrate how different management approaches are needed in low-N-input versus high-N-input dairy cattle systems and that improvements can be made in both systems.

Technical Abstract: In most parts of Sub-Saharan Africa fertilizers and feeds are costly, not readily available, and used sparingly in agricultural production. In many parts of Western Europe, North America, and Oceania fertilizers and feeds are relatively inexpensive, readily available, and used abundantly to maximize profitable agricultural production. A case-study dairy-systems approach was used to illustrate how differences in feed and manure management in a low-N-input dairy cattle system (Niger, West Africa) and a high-N-input dairy production system (Wisconsin, USA) impact agricultural production and environmental N loss. In Niger, an additional daily feed N intake of 114 g per dairy animal unit (AU, 1000 kg live weight) could increase annual milk production from 560 to 1320 kg AU-1, and the additional manure N could greatly increase millet production. In Wisconsin, reductions in daily feed N intake of 100 g AU-1 would not impact milk production but decrease urinary N excretion by 25% and ammonia and nitrous oxide emissions by 18% to 30%. In Niger, compared to the practice of housing livestock and applying dung only onto fields, corralling cattle or sheep on cropland (to capture urinary N) increased millet yields by 25% to 95%. The additional millet grain due to dung applications or corralling would satisfy the annual food grain requirements of 2-5 persons, the additional forage would provide 120 to 300 more days of feed for a typical head of cattle, and 850 to 1600 kg ha-1 more biomass would be available for soil conservation. In Wisconsin, compared to application of barn manure only, corralling heifers in fields increased forage production by only 8 to 11%. The application of barn manure or corralling increased forage production by 20% to 70%. This additional forage would provide feed for 2-4 heifers per year. Study results demonstrate how different approaches to feed and manure management in low-N-input and high-N-input dairy cattle systems impact milk production, manure N excretion, manure N capture, N recycling and environmental N loss.