Maximizing Milk Production on Wisconsin Pastures: Lessons from the Paddock
Principal Investigator:
- Mark Renz
University of Wisconsin
Extension Weed Specialist
608-263-7437
[email protected]
website
Abstract
Organic dairies that fail to maximize pasture production may have reduced milk production. Pasture management, forage nutritive value, and soil fertility are known to influence milk production, but have not been studied concurrently. We evaluated agronomic and management variables on 20 organic dairies in the Upper Midwest to determine factors associated with high levels of milk production. At each farm, two pastures were sampled before grazing in June and September for species composition, productivity, and nutritive value. Soil samples and management information were collected in October. Potential milk production was calculated based on forage productivity, cell wall concentration and digestibility, and estimated dry mater intake by a 500 kg cow. A classification and regression tree was used to prioritize the factors associated with potential milk production. Improved legume cover exceeding 40% in June increased milk production by 97%. Non-improved grass cover less than 70% in June and September increased milk production by more than 75%. Maintaining residual sward height at 9 cm or greater throughout the year was also associated with increased milk production. Soil fertility was not highly associated with milk production. Our results suggest that to increase milk production from pasture, management of residual height, improved legume and non-improved grass populations should be prioritized.
Introduction
Wisconsin has the largest number of organic dairies in the United States with over 450 dairy farms that represents more than 25% of the nation’s certified organic dairy farms (USDA NASS, 2014). Despite the large amount of organic dairy operations in Wisconsin, interest in expansion of existing and new operations exist due to consumer demand for organic milk (Greene and McBride, 2015). With the challenges that expanding operations face (e.g. purchasing land), interest in maximizing pasture performance exist. Previous research has shown that pasture productivity, forage quality, soil fertility and pasture management are all critical to maximizing milk production, but these factors have been observed to vary widely across farms. We visited pastures from organic dairies throughout Wisconsin to assess productivity and determine what facets measured could be improved to maximize milk production.