This is the team’s first week of monitoring alfalfa heights for first cutting quality in 2025. The full report for our six-county region (Broome, Cayuga, Chemung, Cortland, Tioga, and Tompkins Counties) can be found in the following link: Alfalfa Height Reporting Sheet 5.6.25.
This week’s updates:
Alfalfa heights from around the region are very very different for our first full week – both between and within counties. Checking your own fields progress is key for dairy farmers looking to harvest grass for lactating dairy quality this year. Additionally, PRO-DAIRY’s Joe Lawrence shared these thoughts in an email to CCE educators:
Based on my observations and the reports of alfalfa heights coming in alfalfa is progressing quickly and grass progress seems to be a bit slower. As happens every few years, this sets up a scenario where alfalfa heights suggest it is time to cut grass; however, grass will still be pretty immature with seedheads still very low in the stem. To avoid negative consequences to 2nd cutting (rapid head emergence, stunted regrowth) the grass seed head needs to be cut off with mowing of first cutting. i.e. 4” above soil surface if following the recommended 4” cutting height is being followed.
Broome: average alfalfa height is over 17″ – but elevation and location are very different for this county’s measurements
Cayuga: alfalfa averaged about 12″ across the county, ranging from only 4″ at one location to 16″ at another
Chemung: as per usual, Chemung county heights are at the higher amount in our region, averaging close to 15″, with some fields over 18″
Cortland: fields here averaged close to 15″ as well, with heights ranging 12-18″
Tioga: average heights here were almost 17″, surprising me as I was checking fields. Range was from 14″ – 19″
Tompkins: the tallest on average heights were here this week, close to 17″, with fields ranging from 14″ – 20″
A Reminder on our Methods
For prediction of NDF content, the height of alfalfa as an indicator is as follows:
- 100% grass stands – cut when nearby alfalfa is 14 inches tall (achieves 50% NDF)
- 50/50 grass/alfalfa stands – cut when nearby alfalfa is 22 inches tall (achieves 44% NDF)
- 100% alfalfa stands – cut when alfalfa is 28 inches tall (achieve 40% NDF)
Predicted days to cut are based on daily NDF increases for grasses of 1.0% point, 50/50 mixed alfalfa/grass stands of 0.8% points, and alfalfa of 0.5% points and are adjusted for the coming week’s weather. Typically NDF increases about 0.8 to 1.2 per day for grasses, with cooler weather being the lower end of the range and warmer weather being the higher end. For alfalfa, NDF increases about 0.4 to 0.7 per day, also dependent upon warm/cool weather.
Next Report
Look for our next report of monitoring heights to come out on Wednesday, May 14th. We will also be updating on grass maturity throughout the month of May and early June, utilizing scissor cuts to help assess maturity for other classes and species of livestock.
In the meanwhile, if you can’t get out to check your fields, call one of us on the team. We’ll be glad to help out.
