County Ag News

Trimming Alfalfa harvest is crucial for feed quality


Alfalfa harvest may be earlier this year. In 2014, we had a cool spring which delayed plant growth for our forage crops. Last year on May 29 Hancock had accumulated 340 Base 50 heat units. This compared to the 30 year average of 486. So far this year as of May 14 Hancock was at 331 heat units compared to the average of 314. Looking at some fields this past week I found plants that were from 15-20 inches tall. I will start sampling alfalfa fields this week for maturity.

One of the challenges for dairy producers is deciding when to harvest their first crop of alfalfa. This date will vary from year to year depending on the amount of warm weather received each spring. Relative feed value is an index used to compare the quality of forages relative to the feed value of full bloom alfalfa. RFV is used to compare similar forages for two important qualities- how well it will be consumed and how well it will be digested. 

Alfalfa quality for dairy cows should be 150 RFV. For animals such as steers, heifers or dry cows the quality may be lower.  When planning when to harvest producers must remember that up to 15 -20 points of RFV will be lost due to harvesting and respiratory losses. 

RFV values for first crop alfalfa in the field can drop as much as 4 to 5 points of RFV per day compared to one or two per day in second or third crop. Growers must plan ahead and make allowances for total harvest time. To average 150 RFV across all fields, you should start cutting when the RFV is around 170 or 180.  Allow for local soil conditions.  

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