Grass Growth and Response to Grazing

1
Grass Growth and Response to Grazing

• Original Power Point Created by Casey Osksa
• Modified by Georgia Agricultural Education
  Curriculum Office
• June 2002

2
Importance of Grasses

• Grasses are the most abundant plant
• Most of the energy and nutrients for livestock
• Forage produces approx. 80 of the red meat
  consumed in the U.S.
• Cheaper gain than concentrates
• Utilize land not suited to crop production

3
Growth and Development

• Tiller growth unit of the grass plant producing
  roots and/or leaves
• Vegetative tillers produce leaves
• Reproductive tillers produce stem, seedhead,
  leaves and roots
• Crown basal area of stem where roots arise
• produces new tillers

4
Vegetative Growth

• All leaves arise from the center of the stem
• older leaves wrap around newer leaves
• base of stem is thicker than top
• growing point of all leaves is near the ground
• protected from livestock
• As leaves emerge, stem extends similar to a
  telescope
• Leaves produce energy for self first, then other
  parts of the plant

5
Reproductive Growth

• When vegetative growth is completed, reproductive
  growth begins
• Produce, flower stalk (culm), and seedhead
  (inflorescence)
• Grazing can remove reproductive portion of plant,
  thus seed production

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Carbohydrate Reserves

• Extra food is stored in the crown and roots
• Needed for winter respiration and spring growth

7
Season of Growth

• Grasses that grow in cooler time of year are
  called Cool Season plants
• Early spring as soon as ground is thawed
• High quality forage in spring, but poor growth in
  hot summer
• May begin to grow again in fall

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Season of Growth

• Warm Season Plants grow in hot summer
• Utilize moisture better, can withstand drought
  better
• Less digestible than cool season
• Cool season plants are in reproductive stage when
  warm season plants begin growth
• livestock will prefer new growth to old
• prefer cool season plants if at the same stage of
  growth

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Which pasture would be better? Warm Season or
Cool Season?

• Actually a mixture of the two would provide new
  growth throughout the summer
• More nutritious vegetation longer
• Only seasonal use if only one type of plant

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Factors Affecting Grass Response to Grazing

• Frequency, Intensity, Season
• Frequency is more important than intensity
• Allow plants to build reserves and grow again
  before grazing (rest)
• Continual grazing is more damaging