Height indicators alfalfa and grass for NDF content are below:

In general we say 100% grass stands should be cut when nearby alfalfa is 14 inches tall to achieve the desired 50% NDF.

Begin cutting 50/50 mixed alfalfa and grass stands when nearby alfalfa is 22 inches tall for the desired 44% NDF.

Begin cutting 100% alfalfa stands when alfalfa is 28 inches tall for desired 40% NDF.

Predicted days to cut are based on daily NDF increases for grasses of 1% point, 50/50 mixed stands of 0.8% points and alfalfa of 0.5% point. NDF usually increases about 0.8 to 1.2/day for grasses expecting the lower end of that range in cooler weather and the higher end in warmer. Alfalfa NDF increases about 0.4 to 0.7/ day again depending on temperatures. Predictions are adjusted for the coming week's weather and right now assuming normal growth.

In the attached spreadsheet locations around the region are listed where we have measured alfalfa height. You can use the location and elevation as a guide to conditions that may be similar to your farm.

The 2017 hay crop is ahead of 2016 first cutting. For 2017 on May 17, 2017 the alfalfa averaged 20 inches tall and only 2% of the fields were 18 inches or less. Triticale and grass fields should be knocked down at this point otherwise you will be losing quality. It is important that you get first cutting off in a timely manner, so if it comes down to making a choice between planting corn or getting first cutting, opt for the first cutting. The warmer summer weather may help the corn but you can't get first cutting quality back and you may lose the advantage of adequate soil moisture to gain a quality second harvest.

Mixed stand harvest should start by the weekend with pure alfalfa stands (28 inches for desired 40% NDF) to follow a week later.





Summary of Alfalfa Height and Prediction of % NDF- May 17, 2017 (pdf; 206KB)