Grazing pastures in the Midwest: Is a weed really a weed?

Authors: KOHMANN, MARTA - University Of Wisconsin; RENZ, MARK - University Of Wisconsin; DUARTE, ARTHUR - University Of Wisconsin; Jaramillo, David; CAVADINI, JASON - University Of Wisconsin; HALFMAN, WILLIAM - University Of Wisconsin

Submitted to: Forage Focus
Publication Type: Popular Publication
Publication Acceptance Date: 2/3/2024
Publication Date: 3/1/2024
Citation: Kohmann, M., Renz, M., Duarte, A., Jaramillo, D.M., Cavadini, J., Halfman, W. 2024. Grazing pastures in the Midwest: Is a weed really a weed?. Forage Focus. MFA Updates, March Issue.

Interpretive Summary:

Technical Abstract: Grazed pastures provide many services to society. They provide forage for livestock that produce milk, meat, and wool, help nutrient cycling through urine and dung as well as through plant decomposition, increase soil organic matter, and many others. Grazing crossed dairy-beef heifers has come up as an additional source of income to dairy producers, and we need more data on how grazing management affects their performance. One of the most important questions is: when should I rotate my animals in the pasture for best animal performance and pasture persistence, while also reducing or minimizing pasture weeds? To answer this question, specialists from USDA Dairy Forage Research Center and UW-Madison are collaborating to evaluate the effect of stocking period (number of days a group of animals stays in a paddock) on these responses. We are currently evaluating 1, 4, and 8 days of stocking period at a large, 20-acre trial at Lancaster Research Station. Rest period (number of days we allow the pasture to rest until the next stocking period) and grazing pressure (animal to forage ratio) are the same across all treatments, to make sure we are only evaluating stocking period effects. Our preliminary data shows that weed biomass was similar across treatments at the beginning and middle of the grazing season. However, at the end of the growing season, weed biomass was greater when cattle were rotated every 8 days and progressively decreased at the 4 days and 1-day rotations. When summed across the whole growing season, weed biomass was similar across treatments. Our data thus far has shown no treatment effect on weed cover, which averaged around 18%. This project will be repeated in 2024, where we will also be able to report animal performance and pasture production parameters.