Competency Area 7: Forage Harvesting Factors
PO 29. Know the optimum development stage for first cutting of alfalfa or perennial grasses.
A. Know the basic procedures for evaluating forage quality of grasses and legumes,
B. Know the ideal forage quality (NDF, ADF, CP, etc.) for alfalfa and perennial grasses.
A.) Know the basic procedures for evaluating forage quality of grasses and legumes.
A number of quality indicators, such as total fiber (NDF), digestibility, fiber digestibility, protein, and Relative Forage Quality (RFQ), are useful for evaluating the quality of a harvested forage. Animal rations can be relatively easily balanced to make up for a shortage of energy or protein, but not fiber. Therefore, forages should be harvested at the optimum fiber content (NDF) for the class of livestock being fed. Morphological stage in alfalfa is a NOT a good indicator of forage quality. Morphological stage in grass is a good indicator of forage quality at later maturity stages, but once the inflorescence emerges from the boot in grasses, optimum forage quality is lost. Spring alfalfa quality is best predicted using the PEAQ equations (Predictive Equations for Alfalfa Quality) developed in Wisconsin, that are based on the maximum height of alfalfa and the maximum growth stage.
Management to produce dry cow forage
- Regular soil testing.
- Set aside fields lowest in K.
- Avoid all forms of K fertilizer, including manure.
- If production declines, include some K fertilizer.
- Harvest spring grass after flowering.
- Use grass re-growth (lowest in K) for cows just prior to calving.
- Competency Area 1: Crop Adaptation
- Competency Area 2: Crop Staging, Growth, and Development
- Competency Area 3: Tillage Systems
- Competency Area 4: Seeding Factors
- Competency Area 5: Seeding Rates and Row Spacing
- Competency Area 6: Considerations in Replanting Decisions
- Competency Area 7: Forage Harvesting Factors
- Competency Area 8: Cropping Systems