Going Green

Thursday, February 7, 2008

Cell Grazing for Improved Pasture Management

Imagine the prairie covered by huge herds of grazing bison. They are constantly moving and constantly eating. Their population density is very high but they rarely graze the same ground for more than a couple of days before moving on. They efficiently utilize the plants that are available to them as they make their way across the grasslands.

It is under such conditions that most of our native grass species evolved. Those plants that thrived under such conditions are the ones that we are familiar with today. They are the species that best utilize our abundant sunlight, good soils and rainfall.

When grazing native or improved pastures, perhaps there would be wisdom in considering the historical grazing patterns under which the forages developed. One method of managing pastures that in many ways resembles the highly concentrated, ever-moving bison herds is cell grazing.

Cell grazing is a pasture management system that divides pastures into small cells that concentrate animals. The basic premise is to graze a cell intensively for a short period of time and then to move the animals to the next cell. Over the course of time, the animals would rotate through all of the paddocks (or cells) and begin the process again. Why is such a system of value?

Forage plants, such as grasses, go through various growth stages. During Stage I growth, a few tentative shoots produce leaves in order to gather the energy from sunshine so that the plant can convert carbon dioxide, water and nutrients from the soil into more plant. This is accomplished through photosynthesis. As the plant becomes better established and is producing enough energy to maintain itself, it moves into Stage II growth. During this second stage, there is slightly less nutritive value in the leaves but abundant production of new growth. This is usually the ideal stage for grazing the plant. If left uneaten, the plant will move into Stage III in which the energy is shifted away from foliage growth and into seed production.

The idea of cell grazing is centered on the growth stages of the grasses to be grazed. Proper timing of moves will enable the grass to produce at its maximum capacity (both for forage production and for energy value) for a longer period of time during the growing season. The timing of animal movement is based on the stage of the plant rather than the calendar. This means that more livestock can be grazed on the same amount of pasture.

There are critical factors that must be considered in a cell grazing system. These include water availability to the animals, the life cycles of the specific forages to be grazed, the cost and type of fencing and the time requirements for monitoring the pasture and moving the animals.

Cell grazing systems require more planning than most traditional grazing systems. Careful attention must be paid to stocking rates, fertilization, a period of rest for the plants, patterns of livestock movement, nutrient value of the forage and the impact of animal density on the particular forage varieties being managed. Mineral supplementation to offset any soil deficiencies may be necessary. It may also be necessary to invest in additional watering facilities as well as fencing. Most cell grazing systems utilize electric fencing as a low-cost and flexible method of dividing pastures.

Cell grazing provides the opportunity for better pasture quality due to the intensive management based on the forage life cycle. It also allows for better utilization of the available forage so that more pounds of beef can be produced on the same amount of land.

This is a great time to evaluate your grazing practices for the coming year. Whether a cell-grazing system is right for a particular operation is something that must be determined by each individual. Whatever the decision, the planning and evaluating process should be beneficial.

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