Post on 28-Mar-2015
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 Vegetation Considerations
Deferment promotes plant succession Increase desirable species Reduce and improve sacrifice areas
Improve forage harvest efficiency Reduce animal selectivity Grazing systems do not change forage
preferences Integrate range improvement practices:
Brush control Prescribed burning Seeding
Grazing Systems Objectives Animal Considerations
Animal production per head and per acre Many rangeland grazing systems will reduce
animal performance
Improve animal management and care Supplemental feeding Health care Artificial insemination
Grazing Systems Objectives Economic Considerations
Reduce costs Facilities such as watering points and
handling equipment Variable inputs, especially labor
Management considerations Facilitate application of improved
management
Definitions for grazing systems 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 Increasing harvest efficiency can
increase animal production Deferment promotes range
improvement through plant succession Deferment reduces harvest efficiency
Designing Grazing Systems 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 Higher stocking rates produce higher gains per
acre when: Precipitation is above average Animals receive supplemental feed
Continuous stocking may increase risk during droughts because of:
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 Focus on Animal Production
Wildlife-animal population equilibrium Focus on maximum animal numbers
Rangeland management-sustainable use
Focus maximizing animal production while sustaining rangeland productivity
(Kothmann and Hinnant, unpublished)
Types of Grazing Systems 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 Purposes include:
Relatively short grazed & non-grazing periods
Control timing of grazing Reduce area selectivity
In humid grasslands and tame pastures: Can increase animal production/acre (not
per animal) through more uniform use of plants
Deferred Rotation Emphasizes deferment of forage use
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 This is a deferred rotation system that
emphasizes cyclic deferment of grazing Pasture and rotation characteristics:
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 Emphasizes a full year’s rest for part of
the grazing area
Used in mountainous areas in western US
Pasture and rotation characteristics:
3-5 pastures per herd One pasture receives 12-months rest Grazing pressure in others increases
Rest-Rotation Grazing Advantages:
Low SR and non-grazing can improve vegetation
Low livestock numbers can provide multiple-use advantages with more forage allocated for wildlife & watershed
Disadvantages: 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
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: 3+ pastures Grazing periods of at least 14 days Non-use periods of at least 60 days
High Intensity-Low Frequency
Advantage: Minimizes competitive advantage for less
preferred plants because animals are forced to be less selective
Disadvantages: 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 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: 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 Advantage:
SDG may improve diet quality because maturation of forage is delayed by repeated defoliation
Centralized watering/handling facilities (wagon-wheel) that can improve livestock management and reduce labor and facilities expenses
Disadvantage: 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
What are your vegetation management goals?
What are your animal production & management goals?
What are your management and economic constraints?