Forage Quality of Alternative Cropping Systems for Organic Dairy Farms in New England.

Organic dairy systems continue to play an important role in transformations of agriculture in the Northeast U.S.  In general, cropping systems on organic dairies are distinct from their conventional counterparts, having greater reliance on pasture, a more diverse crop mix, and minimal on-farm grain production. Since most organic grain is imported into these systems at a premium expense, forage quality is critical for economic survival. Field experiments were established in Orono, ME, in 2006 and 2007, to evaluate four production scenarios on organic dairy farms in the Northeast U.S.: 1) corn (Zea mays L.) silage with grain production; 2) corn silage without grain; 3) no corn silage (perennial forage mixture of Alfalfa (Medicago sativa L.), Perennial Rye (Lolium perenne L.) and Timothy (Phleum pretense L.))  with grain; and 4) no corn silage (perennial forage mixture) and no grain.  Sorghum-sudangrass hybrid [Sorghum bicolor (L.) Moench] and triticale (Triticosecale) harvested at either boot or soft dough stage substituted for corn as a forage source, and grains included barley (Hordeum vulgare L.), high-moisture corn, soybean [Glycine max (L.) Merr.], and triticale.   Neutral and acid detergent fiber (NDF and ADF, respectively) and protein concentration were measured for all crop harvests from 2006 through 2009.  Yield and quality varied widely among the forage crops.  Warm season annuals performed poorly, being highly weather dependent and management intensive. Small grain silages offered flexibility in harvest management for either protein or energy sources of forage. Diets were formulated based on these four scenarios, and were fed to organically managed lactating cows to evaluate economic returns associated with varied cropping systems. This research helps organic dairy farms select crops and production systems appropriate for their farms.