Alfalfa Update: 1st Crop 2016
May 13th, 2016
Robb D. Wock – DPC, Purina Animal Nutrition LLC
Since I last reported on Alfalfa growth & development exactly 1 week ago there has been a mixture of days with very rapid Alfalfa growth and also some days of slower growth. It appears that it is possible that the growth could have met or exceeded 1-1.5 inches / day over the weekend (this past Saturday & Sunday) when temperatures climbed well into the 80’s and beyond, while we’ve otherwise had a much cooler pattern that may have only produced a growth rate of about ½ inch / day. Certainly the cooler nights are slowing down the “maturation” process, which is not all bad considering that we have also been receiving some precipitation.
Plant height measurements are now averaging somewhere between 20-22 inches throughout the field, with the tallest plants at least 24” to possibly 26”. Most stands on average are still vegetative, but there is now evidence that virtually all the taller plants have at least 1 node containing a visible bud. At this height and with budding occurring most of our Alfalfa stands should currently be in range from 175 to 185 Relative Feed Value. 1st crop often is a little more flexible to a higher interpretation of value due to the cooler nights and often “wetter” conditions we experience in early May, so this may allow us just a little more time. However I would have to stand behind my original predictions and tell you that if your goal is to produce Dairy-Quality Alfalfa than I would recommend you begin cutting as soon as you feel the weather allows you the opportunity to get the job done, between May 15thand the 20th. If we are correct in our evaluation of quality and are running around 180 RFV than the losses during harvest would put your STORED quality closer to 160-165. Don’t forget that what we really need is adequate fiber digestibility, or Relative Feed Quality (RFQ), because this is what gives us the best chance to improve Dry-Matter-Intake and maximize performance. The plant has to stay more on the immature side if you want to achieve high RFQ’s … so harvesting earlier is better.
If we use Growing Degree Day (GDD) to estimate plant maturity it appears we would have some more time on our side, perhaps as much as a full week or so depending on where the temperatures land. We are currently at about 600 or so GDD so if we use 700 as a guideline to achieve less than 40% NDF we might have about 8 more days on our side before we start to lose significant quality.
Don’t hesitate to contact me if you need additional assistance. And please harvest safely!