Alfalfa is a power-packed ingredient in cattle rations, especially for the dairy producer. Yet this crop can add more uncertainty to the ration than any other ingredient. That’s because alfalfa’s relative feed value (RFV) can vary drastically.

Lesperance claude
Hay and Forage Product Specialist / New Holland

The RFV depends on the plant variety, maturity at cutting or any of several handling and harvesting conditions. In fact, it’s not uncommon for RFV to range from a low of 100 points to highs over 250.

Having an accurate RFV measurement is critical to profitability for dairy producers. The standard practice for gaining some indication of the hay’s quality is through random core sampling. The problem is: Core samples taken from the same bale can be different and alfalfa quality can vary greatly from one part of a field to another or even within the same windrow. Bales made just minutes apart can often vary 20 to 30 points in RFV.

There is precision farming technology available to producers that can accurately determine and record the RFV and total digestible nutrients (TDN) of every bale on-the-go, right on the baler.

Here’s how it works: The producer takes a windrow sample of the hay, just before or after it’s cut, and sends it to a lab. When the results come back, the value is entered into the program on the baler display. When it’s time to bale, the program takes the weight from the scale and the moisture from the applicator system to calculate the dry matter density, giving the RFV for every bale. The RFV value is displayed on the monitor while baling, is stored in the job records and can also be written to an RFID tag.


The best way to use these precision RFV values is to apply an electronically readable tag to each bale. A bale tagger applies a vinyl tag containing an RFID chip to the twine. On the bale, the tagger system writes information to the tag, including bale, moisture, weight and RFV. It also records the time the bale was made, field location and more. This recorded data can be read back with either a handheld scanner or one that mounts directly to bale-handling machines. Some farms using the system scan the bales as they come out of the field, sorting them by RFV into low-, medium- and high-quality groups.

Identifying the RFV is especially important for dairy producers. Because alfalfa and other hay crops can have feed values that vary drastically, wide swings in quality can affect the amount of hay that needs to be fed, the production potential of that hay and the amount of additional protein and energy needed to balance a ration. Sorting hay according to its quality allows for ration adjustments to keep production consistent so you’re not unknowingly under- or overfeeding metabolizable protein (MP) and metabolizable energy (ME). Lower-quality hay can be fed to dry cows or heifers, while feeding the high-quality hay to high-producing cows can translate to a daily increase of nearly 4 pounds of milk per cow.

Another precision farming tool that helps farmers manage their feed nutrition is near-infrared (NIR) technology. The integration of NIR sensors in forage harvesters enables farmers to adjust length of cut and inoculant applications on-the-go based on moisture levels. It also allows producers to analyze, record and map crop composition during harvest and monitor nutritional values of corn silage, alfalfa silage and high-moisture corn.

The NIR analysis is a huge benefit to dairy producers. When producing livestock feed, producers can monitor and record a host of crop moisture and nutrient parameters in real time with outstanding accuracy. There’s no need to stop to collect samples. Monitored parameters include dry matter (DM), crude protein (CP), crude fat, ash, neutral detergent fiber (NDF) and acid detergent fiber (ADF) – all things that need to be considered in a balanced ration.