CONTROLLED
GRAZING:
Efforts
to increase efficiency, lower costs, and gain more profit from existing
resources and ecologically maintain those resources have led many progressive
ranchers to controlled grazing. Since
its introduction to North America in
the 1970’s controlled grazing
has proven itself a sound management
practice.
Controlled grazing is the management of forage with grazing animals. It limits access to grazing by subdividing pastures with permanent and temporary fences. When compared to controlled grazing practices, traditional grazing methods prove inefficient in terms of energy, production, and operation.
Controlled
grazing results in: increased amounts of forage harvested by animals;
improved forage quality; extended grazing seasons; reduced fertilizer
and herbicide applications; reduced labor and feed costs; fewer weeds;
and environmentally responsible grazing areas.
Fencing
plays a critical role in the success of controlled grazing. New fencing options and technology simplify
controlled grazing more than ever, and help improve results such as
forage quality, production, and environmental impact.
1. Select an area to start. Keep it close to home and small—20-30
acres, and no more than 200 acres. Choose
an area that is uniform in terms of soil, forage, and terrain. Hay pastures make ideal controlled grazing
areas.
2. Plan perimeter and interior fencing. Fencing
for controlled grazing is simple to plan, install, and maintain. Strong, permanent perimeter fences should
be erected. Interior paddocks
are then created with temporary fences. Move
portable fences as cattle need to be moved. If
possible, provide water in each paddock.
3. Put enough livestock into a paddock. Enough
livestock should be concentrated into an area, so that the forage is
grazed to the desired height before the grazed plants begin to regrow. Forage usage should be monitored daily. The smaller the paddock and the higher
the number of livestock, the more uniformly the paddock will be grazed. When the forage in the paddock is grazed
to half its original height, move livestock to a paddock that is ready
to be grazed. Once animals are accustomed to controlled grazing, moving
to new paddocks should only require a few minutes.
4. Monitor forage in the grazed paddocks. The
ideal forage height to begin and end grazing is dependent on the species
and the climate conditions. Forage
plants should be grazed before they get too mature, but not so soon
or so low that the crowns would be damaged. When
forage has recovered, move livestock back into the paddock. Growth rates vary widely during the grazing season. Available moisture is the key to the
length of time for the forage to recover. The
rule of thumb is “fast growth, fast moves; slow growth, slow
moves.”
5. Have backup pasture available. Avoid
grazing paddocks that have not recovered sufficiently. Be
prepared to cut hay in paddocks that grow too rapidly between grazing
periods. Do not try to
follow a set rotation; move livestock to a paddock that is ready to
graze.
6. Relax and be flexible. Severe grazing (grazing very short) can
be offset by a longer recovery period. Let
it rest longer than the others. Monitor
forage and make adjustments as needed. Controlled
grazing is as much art as science.
Rest Periods and Stock Density
Forage
recovery time is the most important aspect of controlled grazing management. Grazing
plants too soon will use up root reserves and weaken them. Waiting
too long to graze plants will reduce forage quality and affect animal
performance.
Stock
density must be managed effectively, too. Low
stock density causes uneven harvesting of forage. Some plants are grazed too short and
are weakened, while some plants are not grazed at all and lose quality. Low stock density also reduces beneficial
hoof action, and can result in trails from livestock who wander around
looking for better forage.
High
stock density causes animals to graze quickly and then rest, resulting
in better performance and less damage to plants. French
farmers have a saying: “Cows
eat with five mouths-one on their head
and four on their feet.” The
less animals walk, the more they eat.
Proper
stock density, like rest periods, varies greatly depending on the forage
resource and the season. In
the spring, stock densities should be higher to allow livestock to
keep ahead of grass. During summer months, when grass quality
declines, stock densities should be increased to force animals to harvest
more forage. In late summer,
stock densities should be reduced to allow grass to build up reserves
for fall. In the fall, depending on type of grass,
stock densities can be increased to increase forage utilization.
Undergrazing
Pitfalls
• Shades our low-growing forage species
• Produces stems of low quality
• Reduces forage production with soil capping
• Wolfy, over-mature impalatable plants
Overgrazing
Pitfalls
• Lowers carrying capacity
• Slows root growth
• Reduces drought tolerance
• Weeds increase
Successful
controlled grazing management depends on the right fencing system. Dependable, controlled grazing fence
systems combine strong, durable perimeter fencing with easily adjusted
interior fencing.
Calculating for Controlled Grazing
Stock density=number
of head divided by size of paddock
Example: One hunderd steers averaging 600 pounds
each are grazing a two-acre paddock. One
hundred steers times 600 pounds equals 60,000 pounds, or 60 head (1,000
pounds live weight). When
divided by two acres, 60 heads equals a stock density of 30 head per
acre.
Stocking rate=number of head
divided by size of grazing area
Example: One hundred steers averaging 600 lbs
each are grazing a 40-acre cell that is divided into 2-acre paddocks. That equals 60 head (1,000 pounds live
weight) divided by 40 acres for a stocking rate of 1.6 head per acre.
Rest period=(number of paddocks
times grazing period) minus one grazing period
Example: When grazing 20 paddocks for two days each, the
rest period for each paddock is 40 days minus one grazing period, or
38 days. If the grazing period were one day, the
rest period would be 19 days.
Carrying capacity=amount of
forage available divided by number of head
Example: a 40-acre pasture produces an average
of 3,500 pounds of dry matter (forage less moisture) per acre per month
from March to August. Normal
harvest yields 2,000 pounds per acre per month. A
600-pound steer will eat approximately 3% of its bodyweight, or 18
pounds per day. Dividing 2,000 pounds by 18 pounds equals
111 steers. Therefore,
the carrying capacity is 111 steers, or 66 animal units per acre per
month.
Residual dry matter=amount of forage minus amount
of forage harvested
Example: A
two-acre paddock contains 3,500 pounds of dry matter per acre for a
total of 7,000 pounds of dry matter. One
hundred steers will eat 1,800 pounds per day or 3,600 pounds of dry
matter in two days. This
will leave 3,400 pounds of residual dry mater or 1,700 pounds per acre. The
more dry matter left, the faster the paddock will recover.
Profit per acre=[(sale weight
x price) minus costs] divided by number of acres
Example: One hundred 600-pound steers gain 300
pounds and sell for $75/cwt or $675 each, less a 3% death loss, for
a total of $65,475. Each
steer costs $450, plus $50 in medicine, fencing and pasture for a total
for $50,000. This means a gross profit of $15,475,
which, divided by 40 acres, means $387 gross profit per acre.
The Difference Between Stock
Density and Stocking Rate
Stock
density is the number of animals grazing a paddock. It is often confused with stocking rate, which is the number
of animals on the property. For
example, a 500-acre ranch with 1,000 steers would have a stocking rate
of two steers per acre. Dividing
the ranch into 20 25-acre paddocks and putting all the steers into
one paddock would provide a stock density of 40 steers per acre. Strip-grazing
each paddock five times (five 5-acre strips per paddock) would give
a stock density of 200 steers per acre. However, the stocking rate of two steers per acre would not
change.
Adapted
from: Small Farm Today;
August 1999
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