Dairy farms should prioritize the first cutting of alfalfa over other field tasks to ensure high-quality haylage. With farms balancing planting, manure spreading, and daily chores, timely alfalfa harvest is essential to maintaining forage quality.
Importance of First Cutting Alfalfa
- The first cutting is traditionally the highest-yielding, making up the largest portion of the season’s total yield.
- Delays in harvesting can significantly reduce quality due to an increasing stem-to-leaf ratio, leading to higher fiber content (NDF), reduced digestibility, and lower nutrient absorption by dairy cows.
- The timing of the first cut determines subsequent harvest windows, influencing the second, third, fourth, and possibly fifth cuttings.
Determining the Optimal Harvest Time
To balance yield and quality, multiple tools can help determine the best time for the first cutting:
1. Growing Degree Days (GDD)
- Measures accumulated heat units above 41°F, indicating plant growth progress.
- Ideal range for first cutting: 680-750 GDD.
- Storage facilities impact the optimal GDD target.
- Should be used as an initial indicator before field scouting.
2. Plant Height
- Alfalfa is typically ready for harvest when the tallest plants (at the bud stage) reach 28 inches.
- A practical field method to estimate readiness.
3. Predictive Equations for Alfalfa Quality (PEAQ)
- Uses plant height and development stage to estimate feed quality metrics like:
- Relative Feed Value (RFV)
- Relative Feed Quality (RFQ)
- Neutral Detergent Fiber (NDF)
- The PEAQ stick provides quick field estimates but should be supplemented with lab testing for precise ration formulation.
The Impact of Delayed Harvest
- In times of unusually warm spring weather this can accelerate plant growth, potentially moving the first cutting date earlier than usual.
- The timing may overlap with corn planting, requiring producers to choose between completing planting or harvesting alfalfa first.
Key Considerations:
- Corn Planting vs. Alfalfa Harvest:
- A short delay in corn planting (3-4 days) has minimal impact on fall yields.
- Delaying alfalfa harvest results in rapid quality decline, reducing its value for lactating cows and limiting high-quality forage inventory.
- Forage Quality Decline:
- Each day past the optimal cutting window sacrifices forage quality.
- Delayed cutting shifts alfalfa from high-quality lactation feed to lower-quality forage suited for dry cows or heifers.
Conclusion
First cutting alfalfa should be a top priority for dairy farms. By monitoring GDD, plant height, and forage quality indicators, producers can optimize both yield and quality. Strategic timing ensures high-quality forage, supporting dairy herd nutrition and long-term productivity.
