Molasses supplementation of grazing dairy cows: summary of case study, continuous culture fermenter trials, and controlled research farm study

Authors: HOFFMAN, KAREN - Natural Resources Conservation Service (NRCS, USDA); Soder, Kathy; BRITO, ANDREW - University Of New Hampshire

Submitted to: Extension Fact Sheets
Publication Type: Other
Publication Acceptance Date: 8/5/2011
Publication Date: 8/10/2011
Citation: Hoffman, K., Soder, K.J., Brito, A. 2011. Molasses supplementation of grazing dairy cows: summary of case study, continuous culture fermenter trials, and controlled research farm study. USDA-NRCS Fact Sheets. p. 1.

Interpretive Summary: An interpretive summary is not required.

Technical Abstract: This fact sheet summarizes the results of a three-tiered research approach (case study, two continuous culture fermenter studies, and a controlled research farm study) to evaluate molasses as an alternative supplement source for grazing dairy cows. A two-year case study of a New York organic dairy farm showed that increasing the energy content of the diet (with the addition of starch such as corn) would have resulted in increased milk production and body condition score, since energy was the first limiting nutrient. Continuous culture fermenter studies conducted at University Park, PA, resulted in little difference in ruminal fermentation of pasture diets supplemented with molasses, corn, or a combination of molasses and corn, indicating that there may be other management and feeding factors that impact response to molasses supplementation, resulting in the variable anecdotal responses observed on organic dairy farms. Finally, results of the controlled research study at the University of New Hampshire where grazing Jersey cows were supplemented with either molasses or corn indicated that baleage intake increased slightly with molasses supplementation, possibly due to increased palatability of the molasses top-dressed on the supplemental baleage. Pasture intake was slightly higher for cows supplemented with molasses. However, there were no differences in milk production, milk composition, or nitrogen utilization. The decision to feed molasses or corn meal as an energy supplement to grazing dairy cows should be based on the cost of each feed on a dry matter basis. Grazing management, genetics, environment, and other farm-specific characteristics are most likely to influence the success or failure of cow performance rather than energy source.