Grazing Management: Systems

Transcription

1 Grazing Management: Systems

2 GRAZING SYSTEMS? Why would you want to use a grazing system? What do you expect from your grazing system?

3 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

4 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

5 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

6 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.

7 THE GOAL AND CHALLENGE Increasing harvest efficiency can increase animal production Deferment promotes range improvement through plant succession Deferment reduces harvest efficiency

8 DESIGNING GRAZING SYSTEMS Considerations of grazing frequency and grazing intensity when designing grazing systems

9 Relationship (linear) between average annual precipitation and recommended proper stocking rate at locations from Sonora, TX to Manyberries, Canada

10 Generalized animal production responses to stocking rate

11 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

12 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)

13 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

14 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

15 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

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17 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

18 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

19 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

20 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 nongrazing 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

21 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)

22 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

23 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

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27 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?