Cutting management key to optimizing alfalfa yield

By Gary Sliworsky
Ag rep, Emo

The following is part one of a two-part article on cutting management of alfalfa:
Cutting management of alfalfa is important to optimize yield, quality, and persistence.
Harvest schedules are dependent on the type of livestock being fed and the appropriate forage quality goals. Some dairy farmers place more emphasis on high-quality, frequently-cut, good-yielding stands that last for three years and are less concerned about alfalfa persistence.
Others will delay harvesting with the goal of higher yields and greater plant persistence, but lower feed quality.
Forage crops decline in feeding value as they mature. In a pure alfalfa stand, once alfalfa buds appear, feeding value will decline about 0.2 percent per day in crude protein and about 0.4 percent per day in digestibility.
Delays in cutting result in significantly lower forage quality.
Of course, finding a window of dry weather can complicate things even further. With a large acreage of forage, it is advisable to start cutting earlier to ensure the later cut material still will have adequate quality.
For a high-producing dairy herd, forage must be high in digestible energy and protein. The benchmark analysis for alfalfa for high-producing dairy cows is considered to be 20 percent crude protein (CP), 30 percent acid detergent fibre (ADF), and 40 percent neutral detergent fibre (NDF).
This high quality requires an aggressive, early starting three-cut system. Beef feedlots also should strive for earlier-cut, higher-quality alfalfa forage.
For beef cows, the most appropriate hay is higher in grass content, more mature, and higher yielding, and therefore is lower in protein and digestibility.
Many recreational horse owners prefer hay that is more mature and contains more grass.
Because it is very important that horse hay not be “rained on” and be entirely free of mould, waiting for the right weather is the priority.
The first-cut harvest date will dictate the total season harvest schedule. As a general rule of thumb, for high quality, first-cut forage should be cut at mid-bud to late-bud stage.
Cutting at the pre-bud (vegetative) or early-bud stage will result in reduced yields and may weaken the stand. Extremely low fibre levels may result in nutritional problems.
Delay cutting fields that have been weakened by winter stress to allow plants to recover.
Developmental stages of legumes (stage of maturity and definition):
•Late vegetative—no visible buds; stem at least 12” tall.
•Early bud—visible flower buds on at least one stem.
•Mid-bud—50 percent of stems have at least one bud.
•Late bud—75 percent of stems have at least one bud, but no visible flowers.
•First bloom—flowers on at least one stem.
•1/10 bloom—10 percent of stems have at least one flower.
•Mid-bloom—50 percent of stems have at least one flower.
•Full bloom—75 percent of stems have at least one flower.

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