Grass Growth and Response to Grazing

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

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

Vegetative Growth l 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 l As leaves emerge, stem extends similar to a telescope l Leaves produce energy for self first, then other parts of the plant

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

Carbohydrate Reserves l Extra food is stored in the crown and roots l Needed for winter respiration and spring growth

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

Season of Growth l Warm Season Plants grow in hot summer l Utilize moisture better, can withstand drought better l Less digestible than cool season l 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

Which pasture would be better? Warm Season or Cool Season l Actually a mixture of the two would provide new growth throughout the summer l More nutritious vegetation longer l Only seasonal use if only one type of plant

Factors Affecting Grass Response to Grazing l Frequency, Intensity, Season l Frequency is more important than intensity l Allow plants to build reserves and grow again before grazing (rest) l Continual grazing is more damaging