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Test your forage quality IQ

Progressive Forage Editor Lynn Jaynes Published on 09 January 2018
alfalfa-grass stand

At the recent Western Alfalfa and Forage Symposium in Reno, Nevada, participants were asked to respond to a clicker survey-quiz, as presented by forage specialists Glenn Shewmaker (University of Idaho), Dan Putnam (University of California – Davis) and Shannon Mueller (University of California – Fresno Extension).

Here are some of the questions. Test your own awareness of what influences forage quality.

Q: Growth of alfalfa during cool temperatures frequently results in:

  1. Higher protein levels
  2. Higher NDF/ADF (fiber) levels
  3. Accumulation of soluble carbohydrates, which improve the digestible nutrients (TDN)
  4. Lower leaf percentage

A: #1

Stem growth is reduced during cool temperatures, which results in lower fiber concentrations and higher protein levels (probably because the same amount of protein is produced but there is less fiber mass from the stems to dilute it).

Q: Growth of alfalfa during very hot periods often results in:

  1. Higher ash content
  2. Increased ADF and NDF content due to increased respiration
  3. Very low protein content
  4. Higher fiber digestibility

A: #2

Under hotter temperatures you get higher respiration during the night, which burns up sugars and increases buildup of fiber compounds.

Q: Which factors are influenced by cutting schedule?

  1. Yield
  2. Forage quality
  3. Weediness
  4. Stand life
  5. Plant vigor
  6. Root reserves
  7. All of the above

A: #7

All of the above. Yield increases, forage quality declines, weediness is less, stand life is longer, plant vigor is improved and root reserves are increased with a longer cutting interval.

Q: When managing harvests for high quality, what might you be sacrificing?

  1. Yield
  2. Stand life
  3. Convenient scheduling
  4. Irrigation management flexibility

A: #1

Yield is one of the biggest sacrifices. Stand life, irrigation and cutting scheduling are also affected. If you said, “All of the above,” you’d also be right.

Q: Which option tends to result in the most soil contamination?

  1. Sickle bar mower/conditioner
  2. Rotary mower/conditioner
  3. Rake height and adjustment
  4. Baler pickup height

A: #2 and less so for #3

Rotary mowers work like giant vacuum cleaners and suck up the dust and deposit it in the windrow. Rakes can also affect ash contamination – and it’s common to put your most inexperienced employee on the rake; that’s a mistake. You want your best employee on the rake to prevent more leaf shatter and ash contamination.

Q: Which type of rake is more likely to have leaf shatter?

  1. Ground-driven
  2. Mechanical (hydraulic or PTO)
  3. Hay merger

A: #2

Mechanical-driven rakes create more leaf shatter because it is more difficult to match ground speed with rake speed; however, a lot depends on adjustments and moisture.

Q: Which of the following is affected by stand density?

  1. Leaf percentage
  2. Crude protein
  3. ADF
  4. Lignin
  5. Stems per crown
  6. Stems per square foot

A: #5

Alfalfa plants sense light availability and closeness of neighbor plants and will compensate to form a canopy fairly efficiently. Stems per square foot is a good predictor of yield, but stems per crown gives a pretty good indication of plant vigor.

Q: High plant density of alfalfa:

  1. Decreases quality due to reduced leaf percentage
  2. May slightly improve quality due to thinner stems
  3. Has an important effect on quality through suppression of weeds
  4. Decreases quality due to leaf shatter
  5. Both #2 and #3

A: #5

Quality may slightly improve due to thinner stems, and it certainly has an important effect on quality through weed suppression.

Q: In swathing the alfalfa:

  1. Narrow windrows are helpful because it slows the drying of the crop and reduces bleaching
  2. Wide windrows with intense conditioning are desirable to hasten drying and reduce crop respiration
  3. Narrow windrows are more convenient for later raking and baling

A: #2

Benefits of a wide swath include faster drying, less respiration and higher forage quality.

Q: Sun bleaching in the windrow:

  1. Significantly lowers the quality since the sun removes the green color
  2. Does not affect the ADF, NDF, CP or digestibility of the hay at all
  3. Removes protein from the leaves, lowering quality
  4. Can affect marketing of the hay, but this is widely misunderstood
  5. Both #2 and #4

A: #5

Hay bleaching has no effect on quality.

Q: Problems with hay testing results are most often a result of:

  1. Inadequate sampling methods
  2. Using NIRS rather than wet chemistry methods
  3. Variation between labs
  4. Within-lab errors
  5. Problems with interpretation of results

A: #1

As much as we don’t like to hear the variation in results was our own fault, it often is.

Q: The three most important management factors to consider for high forage quality are:

  1. Choosing the right variety, maintaining high plant density and high rates of irrigation
  2. Proper fertilization, choosing the best soil type and controlling diseases
  3. Controlling weeds, proper harvest schedule and skill in harvest management
  4. Controlling sucking insects, harvesting in the afternoon and narrow windrows

A: #3

Summary

The greatest influences on forage quality are:

  • Cutting schedule (which influences maturity at harvest)
  • Relative proportion of leaf and stem (which is influenced by many factors including maturity, pests and diseases, variety, temperatures during growth, irrigation management, harvest and curing)
  • Presence of weeds
  • Environmental effects

In short, any agronomic practice that impacts leaf-to-stem ratio or plant maturity at harvest will affect forage quality.  end mark

Lynn Jaynes
  • Lynn Jaynes

  • Managing Editor
  • Progressive Forage
  • Email Lynn Jaynes

PHOTO: An alfalfa-grass stand thrives near Elverson, Pennsylvania. Photo by Lynn Jaynes.

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