The first crop of Midwest forage has largely been described as ‘Average’ in 2015. After initial review of results coming through the analysis laboratory this spring and into summer, RFQ values are roughly 135 to 145 and NDF digestion values appear average to slightly above average. While many factors can affect forage quality each year, reaping optimal forage is possible by correctly assessing and adjusting those variables that are in our control – first and foremost being the cut timeline. Each crop through the summer provides a new opportunity to fine-tune forage quality for the best animal performance at feedout, with the help of the right forage assessment tool.
The first part of this forage timeline series focused on walking away from utilizing the calendar in determining the cut timeline for first crop – whether that be alfalfa, or alfalfa and grass mixes. Part two of this forage timeline series will focus on the scissor clipping method of forage assessment.
Scissor clipping forage assessment
Hand harvesting field samples (or scissor clips) was the first method to be consistently used for forage assessment, outside of the calendar. Scissor clippings apply to all cuttings and all forage types, including pastures. Both this approach and the previously discussed PEAQ stick forage assessment measure nutritive value and offer an RFQ (Relative Feed Quality) value to assess quality. With a basic understanding of how crops mature each day, both PEAQ and scissor clip methods allow farmers to schedule cutting and harvest to consistently achieve desired crop nutritive value, where cutting based on the calendar (e.g. 28 to 30 days) continually fails.
Now that most of first crop is off the field, we look to perfecting our cutting schedule for second crop through the entire forage season – all of which isn’t far away. Traditionally speaking, second crop and after is lower quality than the first, due to lower fiber digestibility. However, assessing value based on a sample gathered via the scissor clipping method can help improve a precision nutrition program by capturing the optimal feed quality from this crop for the animal groups intended.
Scissor clipping focuses on harvesting subsamples throughout the entire field or pasture in an effort to accurately characterize the field. One sample should be harvested for every 10 acres of field. For example, if checking crop quality within a 50-acre field, five single square-foot subsamples should be harvested and mixed together for a composite sample. The resulting RFQ value from a scissor clipping and subsequent laboratory report corresponds to fiber content and digestibility for the field’s crop. After learning the fresh scissor clip RFQ value, growers can expect to lose 10-15 units of RFQ due to leaf loss and fermentation through harvest and ensiling, and roughly five units of RFQ each day the forage grows in the field (due to roughly one unit of Neutral Detergent Fiber (NDF) increase per day). While roughly five units RFQ are lost each day, temperature and rain can also cause positive and negative fluctuations of five units per day.
The ideal cut timeline for each crop through the summer can then be determined by working back from the desired RFQ at feedout. For example, if scissor clip analysis reports 225 RFQ and 185 RFQ is desired for high performing dairy cattle, the crop should be harvested in five days: 225 RFQ - 5 RFQ units lost each of 5 days (25 RFQ units) – 15 RFQ units lost during harvest/ ensiling = 185 resulting RFQ value at feed out.
For demonstrations on how to correctly perform the scissor clipping method in the field for an accurate RFQ measure, check out the video demonstration here: http://bit.ly/scissorclipping
Utilizing forage assessment tools, such as scissor clipping, to improve harvest timing and precision, will ultimately allow us to control and optimize forage quality. Farmers should look to this and other available precision agriculture and nutrition tools to improve forage production management and reap rewards in the barn.
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