In the North Central region, producers typically initiate harvesting when alfalfa maturity reaches bud to early Alfalfa (Medicago sativa L.) has been considered as a biofuel flowering. This often results in three or four harvests feedstock. A system has been proposed to produce electricity from the stems and utilize the leaves as a livestock feed. We determined per season. Harvest maturity is determined by producer the effects of harvest regimes on yield and quality of leaf, stem, and need to optimize herbage yield, nutritive value, or nutritotal herbage of six alfalfa entries. We applied three harvest regimes ent yield. Highest herbage nutritive value and intake involving three harvests per year at bud stage or early flower, or two potential usually occur with preflowering alfalfa with the harvests per year at late flower. An early flower harvest regime had highest yields of nutrients at early flowering (Sheaffer et the highest leaf yield (average of 5.6, 4.5, and 4.5 Mg ha Ϫ1 for the al., 1988). Herbage harvested at full bloom is expected to early flower, late flower, and midbud regimes, respectively), and the have a higher stem proportion than less mature herbage late flower harvest regime had the highest stem yield (average of 5.8, (Fick and Holthausen, 1975; Kilcher and Heinrichs, 5.3, and 3.9 Mg ha Ϫ1 for the late flower, early flower, and midbud 1974). A biofuel production system that adds value to regimes, respectively). Leaf concentration decreased with increased stem components of alfalfa may favor a shift to harvestherbage maturity (average of 540, 517, and 458 g kg Ϫ1 for the midbud, early flower, and late flower regimes, respectively) and was associated ing at more mature stages with fewer harvests per with total herbage crude protein (CP) (r ϭ 0.65, P Ͻ 0.05) and acid-season. detergent fiber (ADF) and neutral-detergent fiber (NDF) (r ϭ Ϫ0.76, Recommended harvest schedules for modern alfalfa P Ͻ 0.05). Harvest regime did not affect total seasonal herbage yield cultivars in a biofuel system are unknown because the or stand persistence. Alfalfa entries differed in herbage quality, leaf relative value of leaf and stem components is expected concentration, and leaf yield, but did not consistently differ in total to vary with energy and livestock feed prices. Compared herbage or stem yield. Herbage yield and quality differences among with the currently used three-or four-cut schedules, a entries were similar for all harvest regimes. Producers can affect stem two-cut schedule with alfalfa harvested at full bloom and leaf yields by selection of harvest regime.

The US dairy industry has realized tremendous improvements in efficiencies and milk production since the 1940s. During this time, farm and total cow numbers have decreased and average herd size has increased. This intensification, combined with the shift to a largely urban public, has resulted in increased scrutiny of the dairy industry by social and environmental movements and increased concern regarding the dairy industry's sustainability. In response to these concerns, a group of scientists specializing in animal welfare, nutrient management, greenhouse gas emissions, animal science, agronomy, agricultural engineering, microbiology, and economics undertook a critical review of the US dairy industry. Although the US dairy system was identified as having significant strengths, the consensus was that the current structure of the industry lacks the resilience to adapt to changing social and environmental landscapes. We identified several factors affecting the sustainability of the US dairy industry, including climate change, rapid scientific and technological innovation, globalization, integration of societal values, and multidisciplinary research initiatives. Specific challenges include the westward migration of milk production in the United States (which is at odds with projected reductions in precipitation and associated limitations in water availability for cattle and crops), and the growing divide between industry practices and public perceptions, resulting in less public trust. Addressing these issues will require improved alignment between industry practices and societal values, based upon leadership from within the industry and sustained engagement with other interested participants, including researchers, consumers, and the general public.

No abstract

Ammonia gas is the only significant basic gas that neutralizes atmospheric acid gases produced from combustion of fossil fuels. This reaction produces an aerosol that is a component of atmospheric haze, is implicated in nitrogen (N) deposition, and may be a potential human health hazard. Because of the potential impact of NH3 emissions, environmentally and economically, the objective of this study was to obtain representative and accurate NH3 emissions data from large dairy farms (>800 cows) in Wisconsin. Ammonia concentrations and climatic measurements were made on 3 dairy farms during winter, summer, and autumn to calculate emissions using an inverse-dispersion analysis technique. These study farms were confinement systems utilizing freestall housing with nearby sand separators and lagoons for waste management. Emissions were calculated from the whole farm including the barns and any waste management components (lagoons and sand separators), and from these components alone when possible. During winter, the lagoons' NH3 emissions were very low and not measurable. During autumn and summer, whole-farm emissions were significantly larger than during winter, with about two-thirds of the total emissions originating from the waste management systems. The mean whole-farm NH3 emissions in winter, autumn, and summer were 1.5, 7.5, and 13.7% of feed N inputs emitted as NH3-N, respectively. Average annual emission comparisons on a unit basis between the 3 farms were similar at 7.0, 7.5, and 8.4% of input feed N emitted as NH3-N, with an annual average for all 3 farms of 7.6 +/- 1.5%. These winter, summer, autumn, and average annual NH3 emissions are considerably smaller than currently used estimates for dairy farms, and smaller than emissions from other types of animal-feeding operations.