Estimating Fiber Content of Alfalfa in Fields Across Ohio

By Mark Sulc and Les Ober et.al

Alfalfa stands in Ohio had some early growth due to the warmer temperature in early April. Although it’s been cooler over the past couple of weeks, alfalfa growth has slowly been progressing. While fields start to dry out this week it’s a good idea to start thinking about estimating neutral detergent fiber (NDF) in pure alfalfa stands.

It is common for many growers to base harvest decisions primarily on alfalfa maturity; however, variable weather conditions affect the rate of bud and flower development in alfalfa and this method can be inaccurate.

A method developed years ago using alfalfa maturity and height still provides an accurate guide for making harvest timing decisions by estimating neutral detergent fiber (NDF) of the standing crop. This method uses height and maturity stage to estimate NDF in pure alfalfa stands. Visit https://forages.osu.edu/sites/forages/files/imce/Estimate%20Alfalfa%20NDF.pdf for instructions on how to estimate NDF in pure alfalfa fields.

Below are a few %NDF estimations across Ohio. Alfalfa growers should start harvesting as soon as fields dry off and a weather window opens, especially in Southern Ohio. Over the next few weeks we will be monitoring and reporting alfalfa NDF. This week’s estimated alfalfa NDF at three field locations is as follows:

            Clark County, May 10: 34.8% NDF

            Stark County, May 10:  33% NDF

            Geauga County, May 10: 29% NDF

In addition to making harvest decisions on alfalfa fields, grass fields in Southern Ohio are already heading out and pushing past 55% NDF. Cereal rye was reported as being headed out last week. Grasses that have already headed out are past the prime for high producing lactating dairy cows.  Grasses in the early heading stage are still good for feeding other classes of livestock with lower requirements than lactating dairy cows.