Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): Evaluate the effects of substituting corn with molasses supplementation on organic dairy farms. Determine the effects of molasses supplementation on milk production, milk components, body weight and body condition of lactating dairy cows in a feeding trial. Evaluate the profitability (income over feed costs) of molasses supplementation for organic dairy farms. Approach (from AD-416): This study will be conducted on the UNH Research Organic Dairy farm. Sixteen lactating Jersey cows will be utilized in a completely randomized block design. Cows will be blocked by parity, stage of lactation, and milk production, and assigned to one of two supplementation treatments. Treatments will consist of: 1) molasses supplementation of a pasture diet at 10% of total DMI; and 2) corn meal supplementation at 11% of total DMI (similar energy content to the molasses supplement). Supplements will be fed individually, with one-half of the supplement fed at the morning milking and the rest fed at the afternoon milking. Cows will be rotationally grazed during the entire grazing season, with three 1-week periods (June, August, September) for data collection. Pre- and post-grazing pasture mass will be measured daily with a calibrated rising plate meter to estimate pasture intake. Pasture herbage samples representative of that harvested by the grazing cows will be collected for nutrient analysis. Supplements will be sampled weekly and composited monthly. Supplement and herbage samples will be analyzed for nutrient content. Body condition and body weights of the dairy cows will be evaluated once monthly by 3 independent observers using a 5-point scale. To indirectly evaluate nutrient utilization and potential differences in nutrient and pasture intake, milk samples will be collected and analyzed for chemical composition, including milk fat, protein, urea nitrogen, lactose, fatty acids (including conjugated linoleic acid), and somatic cell count. Milk weights will be collected at each milking during the entire grazing season to quantify milk production. Blood and urine samples will be collected twice during each of three collection periods. Blood will be analyzed for glucose, non-esterified fatty acids, and blood urea nitrogen. Urine will be analyzed for purine concentration, an indirect measure of ruminal bacterial production. Grazing behavior will be monitored with the use of behavior recorders fitted to cows for 3 days of each collection period. The project has been completed. Data from the in vitro study has been published, while the manuscript for the cow study is in preparation. Project is awaiting Administrative close-out.
Impacts
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Publications
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