Harvesting high quality first-cut alfalfa remains a major challenge for even the top forage producers. A closer look reveals some reasons why and strategies for improvement.
by Mike Rankin
The author is a crops and soils extension agent in Fond du Lac County, Wisconsin.
First-cut forage is "different". We've heard it said many times, "You need high quality forage to get the most for the least out of a lactating dairy cow". It's also true that harvesting high quality alfalfa in humid areas of the U. S. is a most difficult challenge. Although the technology and a basic understanding of the importance of quality forage is present, alfalfa growers are often faced with poor and unpredictable weather patterns, weed encroachment, and a shortage of time or labor to monitor and harvest their crop at optimum nutritional quality. These factors are especially apparent when the initial spring harvest of alfalfa is considered.
Top producers have problems...
My experience has been that more years than not, large amounts of low quality first-cut forage can be found in many silos and hay mows and that the price is paid during a large portion of the year through lower milk checks or higher feed bills. This often occurs even when there was a strong intent and effort by the producer to make top quality forage. In Wisconsin, forage growers have an annual opportunity to participate in a production program called "Green Gold". As one component of the program, forage yield and quality is measured at each cutting from a chosen field area. Participants in this program are typically better than "average" from the standpoint of yield and understand the importance of an overall management program that includes the production of high quality forage. Alfalfa relative feed value (RFV) and yield data averaged from all program fields is presented in Figures 1 and 2 for years 1989-91. Note that even these producers, who wanted to make their best showing from their best fields, found it difficult to balance yield and quality from first cutting. Rather, large amounts of average to poor quality alfalfa were harvested relative to other cuttings.
The production of first-cut forage offers some unique features from a plant, farm, and environmental perspective. As a general rule, forage digestibility begins higher at early maturity stages but declines faster compared to subsequent cuttings. In fact, it's not unusual to document drops of three to four units in RFV per day from bud through flower maturity stages in the spring. The implication for alfalfa producers is that first-cut has the potential to be some of the highest quality forage produced during the growing season but will be some of the poorest quality forage produced if the calendar and crop are not closely monitored. Cool-season grass growth often abounds in many "alfalfa" stands during the spring. Species such as smooth bromegrass, orchardgrass, timothy, and quackgrass have the overall effect of raising forage fiber levels. The impact can be drastic where first cutting is delayed past the heading stages of the grass. First-cut forage measures 30 - 40 percent of the total-season dry matter yields in typical alfalfa production systems and often accounts for the greatest amount of yield on a "per cut" basis. With this in mind, harvest delays are extremely costly because there is a large amount of standing forage dropping in quality at an accelerated rate. Because there is more forage, it takes more days to harvest a given number of acres compared to subsequent cuts. The snowball effect begins, and before you know it, the last field to be harvested looks more like standing timber than feed for a dairy cow.
First-cut sets the pace...
Experience has shown that the first-cut harvest date largely dictates the total-season harvest schedule. In much of the upper Midwest, any chance of harvesting alfalfa four times before the end of August must be preceeded by an early spring harvest. Where that particular harvest schedule is preferred, research has shown that an early spring harvest is key to acceptable stand persistence. Regardless of harvest schedule, first-cut harvest date "sets the pace" both within and between cuttings for the remainder of the growing season and often impacts available late-summer and fall cutting options. The optimum harvest period for first-cut typically conflicts with other field operations on the farm more than is the case with subsequent cuttings. Depending upon the year, dairy producers may find themselves in a situation where planting, cultivating, or other crop demands leave them short of time and labor to make hay. The impact is sometimes an untimely first-cut harvest of low quality forage.
Finally, there are environmental conditions associated with the first-cut time period that makes the harvest of high quality forage a difficult task. In Wisconsin, this time period coincides directly with our highest probability of rainfall on a given day for the year and the least likelihood of three consecutive days without rain. Rain has a significant effect on lowering forage quality by both delaying the harvest of uncut forage and causing the loss of highly digestible plant components in cut forage that remains on the field. With the previous considerations in mind, it's not surprising that much of the first-cut alfalfa produced in our humid regions makes-up a large percentage of the forage fed and is often of inferior quality to subsequent cuttings. Next, we will explore some strategies to improve first-cut quality and tell you about a "grassroots" effort by some local Wisconsin forage councils to help alfalfa producers monitor and harvest higher quality first-cut forage.
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