CASE STUDY: Molasses as the primary energy supplement on an organic grazing dairy farm1

Organic dairies face many challenges, one of which is the high cost of purchased organic grains. Molasses may be a less expensive energy alternative. However, anecdotal results have been mixed for farms that used molasses as the sole energy source. This research project quantified animal performance on an organic dairy farm that fed molasses over 2 grazing seasons. During the 2008 grazing season, the farmer fed organic liquid molasses (1.36 kg of DM/d) and a corn-based grain mixture (0.45 kg of DM/d) per cow to the mixed-breed dairy herd. In 2009, dairy producer concerns about low BCS and milk production resulted in the farmer decreasing molasses (averaging 1.1 kg of DM/d) and increasing corn (1.0 kg of DM/d) supplementation per cow. Milk production and milk fat were similar (P > 0.05) across both years, whereas milk protein was greater (P < 0.05) in 2009. Milk urea nitrogen was greater (P < 0.05) than recommended throughout both grazing seasons. Using the Cornell Net Carbohydrate and Protein System model, metabolizable energy was the first limiting factor for milk production. Milk production mirrored model-predicted metabolizable energy milk in both years. Income over feed costs was numerically greater in 2008, primarily due to greater milk prices and decreased levels of corn supplementation. Decreasing supplemental rates of molasses and increasing rates of corn meal in 2009 did not result in greater productivity or profitability. However, indicators of animal health and nutritional efficiencies such as BCS and milk protein content were slightly improved in 2009. The cost of molasses in relation to corn meal is an important determinant in making feed-ration decisions on a case-by-case basis.