Weather impact on alfalfa quality assessed by field project

Kathy Lee , Faith Cullens, Michigan State University Extension - May 08, 2012

MSU Extension educators have coordinated a short-term field project to assess the effects of this spring’s unusual weather conditions on the growth and quality of alfalfa across Michigan.

Questions have been asked about the effects of this spring’s unusual weather conditions on the growth and quality of alfalfa across the state. Michigan State University (MSU) Extension educators have coordinated a short-term field project to collect data related to alfalfa quality. The results will be summarized weekly and reported through MSU Extension News. This information can be used by producers and agribusinesses for determining when first cutting alfalfa should be harvested for optimal quality.

A total of 15 alfalfa fields (5 geographic areas, 3 fields per area) will be sampled two or three consecutive weeks, prior to harvest. Geographic areas included in Michigan are:

South (Branch and Hillsdale Counties)
Central (Clinton County)
West Central (Ottawa County)
Thumb (Sanilac and Lapeer Counties)
Northwest (Missaukee and Osceola Counties)

For each field, scissors-cut samples of alfalfa will be collected and NDF (neutral detergent fiber) will be estimated using the PEAQ (Predictive Equation for Alfalfa Quality) method (forage quality stick). GDD (growing degree days, base 41) for each corresponding day of sample collection will be based on data from the closest MSU Enviro-weather station. Wet chemistry NDF results for the scissors-cut samples will be compared to the NDF estimates from GDD (base 41) and PEAQ.

The measure of fiber most commonly used to balance diets of lactating dairy cows is NDF. The optimum concentration of NDF for alfalfa fed to lactating dairy cows is 40 percent. Alfalfa containing 40 perent NDF allows reasonable grain concentrations in the diet while maintaining adequate NDF concentrations. Research at MSU demonstrated that both GDD and PEAQ provide good estimates of NDF for first cutting alfalfa.

We would like to thank the sponsors of this project: Pioneer Hi-Bred Int’l, Mycogen Seeds, Byron Seeds, and Cumberland Valley Analytical Services, Inc. We also express appreciation to Dave Main, MSU laboratory technician, for preparing the alfalfa samples for analysis and to the farmer cooperators for allowing access to their fields.

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