Transcript 5 Grazing Systems

Grazing Management:
Systems
Grazing Systems?
Why would you want to use a grazing system?
What do you expect from your grazing system?
Grazing Systems Objectives
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Vegetation Considerations
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Deferment promotes plant succession
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Improve forage harvest efficiency
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Increase desirable species
Reduce and improve sacrifice areas
Reduce animal selectivity
Grazing systems do not change forage preferences
Integrate range improvement practices:
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Brush control
Prescribed burning
Seeding
Grazing Systems Objectives
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Animal Considerations
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Animal production per head and per acre
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Many rangeland grazing systems will reduce animal
performance
Improve animal management and care
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Supplemental feeding
Health care
Artificial insemination
Grazing Systems Objectives
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Economic Considerations
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Reduce costs
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Facilities such as watering points and handling
equipment
Variable inputs, especially labor
Management considerations
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Facilitate application of improved management
Definitions for grazing systems
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Stocking density – The animal density per unit land
area at one point in time.
Stocking rate – The total animal demand per unit
land area for during a forage year.
Grazing pressure – The ratio of forage demand to
forage available at any point in time.
Cumulative grazing pressure – The ratio between the
total forage demand and forage available for the
entire forage year.
The Goal and Challenge
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Increasing harvest efficiency can increase
animal production
Deferment promotes range improvement
through plant succession
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Deferment reduces harvest efficiency
Designing Grazing Systems
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Considerations of grazing frequency and
grazing intensity when designing grazing
systems
Relationship (linear)
between average
annual precipitation
and recommended
proper stocking rate at
locations from Sonora,
TX to Manyberries,
Canada
Generalized animal production responses to stocking rate
Stocking Rate Considerations
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Higher stocking rates produce higher gains per acre
when:
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Precipitation is above average
Animals receive supplemental feed
Continuous stocking may increase risk during
droughts because of:
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Need to destock when beef prices are low
Need for costly supplements (lack forage)
Long-term reduction in perennial grasses
Three concepts for carrying
capacity
Agronomic-livestock production
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Focus on Animal Production
Wildlife-animal population equilibrium
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Focus on maximum animal numbers
Rangeland management-sustainable use
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Focus maximizing animal production while
sustaining rangeland productivity
(Kothmann and Hinnant, unpublished)
Types of Grazing Systems
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Continuous (Yearlong or seasonal)
Rotation Grazing Systems
Deferred Rotation
Merrill 3-Herd/4-Pasture System (DR type)
Rest-Rotation Grazing
High Intensity-Low Frequency (HILF) System
Short-Duration Grazing
Rotational Grazing Systems
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Purposes include:
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Relatively short grazed & non-grazing periods
Control timing of grazing
Reduce area selectivity
In humid grasslands and tame pastures:
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Can increase animal production/acre (not per
animal) through more uniform use of plants
Deferred Rotation
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Emphasizes deferment of forage use
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Grazing area divided into at least two pastures
allowing non-grazing for part of a year
Generally use 2, 3, or 4 pastures
Merrill 4-pasture 3-herd is an example
Merrill System
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This is a deferred rotation system that
emphasizes cyclic deferment of grazing
Pasture and rotation characteristics:
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Area divided into 4 pastures, used by 3 herds
Each pasture grazed 12 mo, “deferred” for 4 mo
Each pasture is deferred once in each season
during a 4-year cycle
Useful where yearlong grazing is practiced
Winter rest allows soil recovery although
forage may not be actively growing
Rest-Rotation Grazing
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Emphasizes a full year’s rest for part of the
grazing area
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Used in mountainous areas in western US
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Pasture and rotation characteristics:
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3-5 pastures per herd
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One pasture receives 12-months rest
Grazing pressure in others increases
Rest-Rotation Grazing
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Advantages:
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Low SR and non-grazing can improve vegetation
Low livestock numbers can provide multiple-use
advantages with more forage allocated for wildlife
& watershed
Disadvantages:
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Generally reduces animal production per head and
per acre
If SR not reduced significantly, intensive grazing
for full grazing season may damage rangeland
High Intensity-Low Frequency
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HILF grazing emphasizes improvement of
range condition thru use of high grazing
pressure to increase uniformity of forage use
with sufficient non-grazing time for plants to
regrow following grazing
Pasture and rotation characteristics:
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3+ pastures
Grazing periods of at least 14 days
Non-use periods of at least 60 days
High Intensity-Low Frequency
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Advantage:
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Minimizes competitive advantage for less preferred
plants because animals are forced to be less
selective
Disadvantages:
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Individual animal performance decreases when
animals are forced to eat mature, unpalatable
forage
Requires reduction in stocking rate (similar to Rest
Rotation)
Short-Duration Grazing
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SDG emphasizes increased grazing pressure
for short periods to minimize excessive plant
defoliation and to allow rapid regrowth of
grazed plants
Pasture and rotation characteristics:
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 8 paddocks/herd, each with equal forage supply
5 days or less grazing period (shorter during
active plant growth periods than dormant period)
Non-grazing periods < 4-6 weeks
Short-Duration Grazing
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Advantage:
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SDG may improve diet quality because maturation
of forage is delayed by repeated defoliation
Centralized watering/handling facilities (wagonwheel) that can improve livestock management
and reduce labor and facilities expenses
Disadvantage:
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Lots of fencing and high fencing cost
Animal trails in long narrow paddocks
< 60-day growing period in arid areas diminishes
positive effects of repeated defoliation/rest
Custom design your grazing system
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What are your vegetation management
goals?
What are your animal production &
management goals?
What are your management and economic
constraints?