|Rotz, Clarence - Al|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/1996
Publication Date: N/A
Citation: Interpretive Summary: Many dairy farmers in the northern states are asking "what is the best mix of alfalfa and corn forages to use on our farms?" There is not an easy answer to this question since many factors must be considered. Crop yields, milk production level, and relative prices of feed commodities are a few of the more important factors that interact with forage type to influence the performance and profitability of farms. A comprehensive study was conducted using a simulation model of the dairy farm called DAFOSYM. Various amounts of corn silage ranging from none to all of the forage from corn silage were compared on the same simulated farms with the remainder of the forage provided by alfalfa. Similar farm profits were found for all forage combinations indicating that farm economics is not a critical consideration in choosing the most appropriate forage crops for the farm. More important considerations are balanced labor needs for the farm and protection of the environment from excess manure nutrients. The practice of having at least a third of the forage requirement provided by each of the forage crops is recommended to improve crop, manure, and labor management. This information will help dairy farmers develop more efficient farms with less potential for adverse effects on the environment.
Technical Abstract: Two primary roughages for dairy herds are corn silage (Zea mays L.) and alfalfa (Medicago sativa L.). DAFOSYM (The Dairy Forage System Model) was used to compare the relative merits of these two forages when 0, 1/3, 2/3 and all of the forage requirement (DM basis) on a dairy farm comes from corn silage with the remainder from alfalfa. Primary comparisons were the net return above feed and manure costs, but manure management issues and labor requirements were also considered. Economic comparisons were made with a partial budget analysis of representative farms synthesized from research reports and surveys. The all alfalfa system normally gave the highest net return, but differences in net returns across forage systems were small compared to the year-to-year variation caused by weather. Changes in farm size, soil type, crop yield, milk production level, relative prices, and manure handling assumptions did not affect the conclusions of the analysis. In systems using all alfalfa forage, most of the manure must be applied to alfalfa; a practice that is normally discouraged to improve weed control, stand persistence, and yield. All alfalfa systems also produce large amounts of excess manurial nitrogen on the farm. If application of this nitrogen to alfalfa is not compensated by reduced nitrogen fixation, ground water contamination may be an environmental concern. Given the lack of a strong economic advantage among the forage systems, the practice of having at least 1/3 of the forage requirement provided by each of the forage crops is favored to improve crop, manure, and labor management.