Robb D. Wock – Dairy Production Consultant, Purina Animal Nutrition LLC
firstname.lastname@example.org (507) 696-6351
As I scout Alfalfa fields in south-east Minnesota this week I’m finding that growth & development of 2nd-crop is right on track for this time of year. No doubt some of the precipitation we’ve been getting recently is going to help out. However we do have two (2) slightly different stands out there: Stands with vegetative growth averaging 17 inches in canopy height and the most mature stems reaching to 21 inches, and stands with vegetative growth averaging 14-15 inches in canopy height with the most mature stems reaching to 18 inches. This is almost completely due to timing of cut on 1st-crop, with cutting occurring 3-4 days sooner on the taller stands. So at the time of this article the current estimate of forage quality runs in a range of 215-230 Relative Feed Value, and Relative Feed Quality (estimation of forage digestibility) likely about 15-25 points higher @ 230-255 !
I would suggest that in the next 8-10 days we will see stem elongation & growth in the range of 6-8 inches, putting the taller stands up near 24 inches or so in average canopy height and the most mature stems approaching 27 or 28 inches. Shorter stands where 1st-crop cutting was delayed will have an average canopy height of 22 inches and the most mature approaching 25 inches or so. If we assume that “budding” is evident at that time it will put our forage quality estimates at around 170 RFV for the taller stands as we prepare for cutting, and 175-180 for shorter stands. After accounting for field/harvest losses this would be right at the point where we need to cut to achieve Dairy quality !
By in large most of 1st-crop was cut somewhere between May 26th and June 1st, with a few situations either side of this range. So by the time we cut 2nd-crop 8 to 10 days from now (June 23rd-25th) we will have about 25-28 days of growth between cuttings. For some that cut as early as May 25th or 26th they may find it advantageous to take 2nd cutting around the 20the or 21st in order to maximize quality & digestibility, so watch your stands closely ! The weather pattern going forward into this timeframe seems to be more favorable for harvest, so maybe mother-nature will allow us a little better opportunity than she did on 1st-crop. Remember that heat & humidity and “warmer evenings” increases the rate of plant maturity … thus flowering and lignification can occur much more quickly, and that is why we often find ourselves pulling the trigger a little quicker on 2nd, 3rd and 4th crops.
Additionally there is a varietal wildcard that can play a much larger role in the timing of 2nd cutting, and that is if you happen to have “low-lignin” alfalfa such as HARVXTRA. The low-lignin gene will allow you a larger harvest window and thus gives you an opportunity to extend your cutting date to improve tonnage yield while maintaining quality. Also we are seeing some aphid or “bug” infestations, so to maximize your potential you’ll need to understand what you’re dealing with. Don’t hesitate to give myself or one of our Agronomists a call and we can help you evaluate your particular situation. Remember you can NEVER go back in time to improve forage quality, and that’s why I always say you can NEVER plan too far ahead for a good crop ! Take care and harvest safely.