2013 Georgia Grazing School:
Optimizing the size, number, and layout of your paddocks
Productivity Per Animal vs. Per Acre
2013 Georgia Grazing School
Optimizing the size, number, and
layout of your paddocks
Product
animal
Dennis Hancock
Extension Forage Specialist
UGA – Dept. of Crop and Soil Sciences
Undergrazing
Grazing Pressure
Productivity Per Animal vs. Per Acre
Basic Grazing Numbers
Forage
Need
Product
acre
Undergrazing
Optimum
Product
animal
•  Animal Data
§  Animal Weight (lbs)
§  Rate of Dry Matter Intake (DMI, %)
§  Head
•  Grazing Data
Logistics
Available
Forage
Overgrazing
Basic Grazing Numbers
•  Animal Data
§  Animal Weight (lbs)
§  Rate of Dry Matter Intake (DMI, %)
§  Head
•  Grazing Data
Logistics
Available
Forage
§
§
§
§
§
Rest Period (d)
Days in a Given Paddock (d)
Number of Paddocks
Grazing Efficiency (%)
Paddock Size (acres)
§
§
§
§
§
§
Acres Available (acres)
Available Foragebefore (lbs/acre)
Available Forageafter
Available Foragediff
Stocking Rate
Stocking Density
•  Production Data
Dr. Dennis Hancock
Extension Forage Agronomist
§
§
§
§
§
Rest Period (d)
Days in a Given Paddock (d)
Number of Paddocks
Grazing Efficiency (%)
Paddock Size (acres)
§
§
§
§
§
§
Acres Available (acres)
Available Foragebefore (lbs/acre)
Available Forageafter
Available Foragediff
Stocking Rate
Stocking Density
•  Production Data
Grazing Pressure
Forage
Need
Overgrazing
Estimating Forage Need
By % of body weight (Table Data):
Animal Class
Forage Intake Range
Dairy cow
Dairy heifer
Bull
Beef, cow (dry)
Beef, cow (late gest.)
Beef, cow (early lact.)
Beef, stocker (steer)
Beef, stocker (heifer)
Beef, finishing
Beef, replacement heifers
Sheep, ewes (dry)
Sheep, ewes (late gest.)
Sheep, ewes (early lact.)
Horse, Mature (maint.)
Horse, Mature (late gest.)
Horse, Mature (early lact.)
Horse, Weanling (< 600 lbs)
Horse, Yearling (600-1000 lbs)
Goat, nanny (dry)
Goat, nanny (late gest.)
Goat, nanny (early lact.)
(DM as a % of b.w.)
2.0 - 4.0
2.2 - 2.8
1.5 - 1.9
1.7 - 2.0
1.8 - 2.1
1.9 - 2.4
2.4 - 3.2
2.2 - 2.6
2.3 - 2.5
2.0 - 2.4
1.5 - 2.0
2.2 - 3.2
3.0 - 4.8
1.0 - 2.0
1.0 - 2.0
1.3 - 2.6
2.3 - 2.8
2.0 - 2.3
1.5 - 2.0
2.2 - 3.2
2.8 - 4.8
2013 Georgia Grazing School:
Optimizing the size, number, and layout of your paddocks
Estimating Forage Need
Estimating Forage Need
By % of body weight (Table Data):
By % of body weight (Table Data):
Animal Class
Forage Intake Range
Dairy cow
Dairy heifer
Bull
Beef, cow (dry)
Beef, cow (late gest.)
Beef, cow (early lact.)
Beef, stocker (steer)
Beef, stocker (heifer)
Beef, finishing
Beef, replacement heifers
Sheep, ewes (dry)
Sheep, ewes (late gest.)
Sheep, ewes (early lact.)
Horse, Mature (maint.)
Horse, Mature (late gest.)
Horse, Mature (early lact.)
Horse, Weanling (< 600 lbs)
Horse, Yearling (600-1000 lbs)
Goat, nanny (dry)
Goat, nanny (late gest.)
Goat, nanny (early lact.)
(DM as a % of b.w.)
2.0 - 4.0
2.2 - 2.8
1.5 - 1.9
1.7 - 2.0
1.8 - 2.1
1.9 - 2.4
2.4 - 3.2
2.2 - 2.6
2.3 - 2.5
2.0 - 2.4
1.5 - 2.0
2.2 - 3.2
3.0 - 4.8
1.0 - 2.0
1.0 - 2.0
1.3 - 2.6
2.3 - 2.8
2.0 - 2.3
1.5 - 2.0
2.2 - 3.2
2.8 - 4.8
Animal Class
(DM as a % of b.w.)
Beef, cow (dry)
Daily Forage Need - Calculator
Rest Period and Occupancy depend
on the Growth Curve
•  Animal Data
12000
§  Animal Weight (lbs)
§  Rate of Dry Matter Intake (DMI, %)
§  Head
Available
Forage
Rest Period (d)
Days in a Given Paddock (d)
Number of Paddocks
Grazing Efficiency (%)
Paddock Size (acres)
§
§
§
§
§
§
Acres Available (acres)
Available Foragebefore (lbs/acre)
Available Forageafter
Available Foragediff
Stocking Rate
Stocking Density
Forage Mass
(dry lbs/acre)
§
§
§
§
§
•  Production Data
Target Height (inches)
Begin Grazing End Grazing*
Extension Forage Agronomist
4000
2000
0
0
5
10
15
20
25
30
Days of Growth
Recommended
Rest Period (days)
Alfalfa (grazing types)
10-16
2-4
Annual Ryegrass
6-12
3-4
Bahiagrass
6-10
1-2
Bermudagrass
6-12
2-6
Clover, White
6-8
1-3
Clovers, Other
8-10
3-5
Orchardgrass
8-12
3-6
Pearl millet
20-24
8-12
Small grains
8-12
4
Sorghum/sudan
20-24
8-12
Switchgrass
18-22
8-12
Tall Fescue
4-8
2-3
* Height at end of grazing may need to be higher to optimize intake
of quality forage or vigorous re-growth.
Dr. Dennis Hancock
8000
Available Forage
6000
(dry mass/unit
area)
Grazing Rules of Thumb
Crop
1st Growth Period
2nd Growth Period
3rd Growth Period
4th Growth Period
10000
•  Grazing Data
Logistics
1.7 - 2.0
2400 lbs/d= 1200 lb cow x 2.0%/hd/d x 100 hd
Basic Grazing Numbers
Forage
Need
Forage Intake Range
15-30
7-25
10-20
10-20
7-15
10-20
15-30
10-20
7-30
10-20
30-45
15-30
35
40
45
50
2013 Georgia Grazing School:
Optimizing the size, number, and layout of your paddocks
Paddock Number
Paddock Size
How many paddocks should I use?
•  Ideally, one should first consider the
needs of the grass.
How big should my paddocks be?
•  This is where it all comes together…
§  But, there’s one element we still need to
measure.
§  We’ll come back to that!
§  In the meantime, let’s refresh our memory on
grazing efficiency.
§  How much rest period is needed?
§  How long should I keep them in a paddock?
Ø  i.e., how many days between rotations?
Number of
Days of Rest
=
+1
Paddocks
Days of Grazing
9 Paddocks =
Paddock
Animal Weight x %DMI x Head x Days in Paddock
=
Size
Available Foragediff x Grazing Efficiency %
24 days of rest + 1
3 days of grazing
Efficiencies of Grazing and
Mechanized Harvest
Method
Efficiency
Grazing
Continuous Stocking
Slow Rotation (3-4 paddocks)
Moderate Rotation (6-8 paddocks)
Strip Grazing, Daily Rotation
30-40%
50-60%
60-70%
70-80%
Mechanical
Hay
30-70%
Silage
Green Chop
60-85%
70-95%
The Primary Calculations
Basic Grazing Numbers
Forage
Need
•  Animal Data
§  Animal Weight (lbs)
§  Rate of Dry Matter Intake (DMI, %)
§  Head
•  Grazing Data
Logistics
Available
Forage
§
§
§
§
§
Rest Period (d)
Days in a Given Paddock (d)
Number of Paddocks
Grazing Efficiency (%)
Paddock Size (acres)
§
§
§
§
§
§
Acres Available (acres)
Available Foragebefore (lbs/acre)
Available Forageafter
Available Foragediff
Stocking Rate
Stocking Density
•  Production Data
Convinced?
Then, here’s how:
12 ac.
Available = Paddock x Number of
Acres
Size
Paddocks
Paddock
Animal Weight x %DMI x Head x Days in Paddock
=
Size
Available Foragediff x Grazing Efficiency %
Number of
= Days of Rest + 1
Paddocks
Days in Paddock
Grazier's Arithmetic: A Grazing Calculator
Dr. Dennis Hancock
Extension Forage Agronomist
•  Do a pasture inventory.
§  Acreage, water, soil fertility…
•
•
•
•
•
Seek advice.
Identify cost-assistance opport.
Sketch out the “ideal.”
Develop a phase-in plan.
Use training wheels.
§  Temporary: Learning/Laborious
§  Permanent: Convenient/Fixed
•  Build in flexibility.
8
ac.
9
ac.
9
ac.
8
ac.
20 ac.
6 ac.
30 ac.
2013 Georgia Grazing School:
Optimizing the size, number, and layout of your paddocks
Rules of Thumb:
•  A 2-4 day rotation works best
for most beef operations.
§  For tall fescue based pastures,
10 – 15 paddocks is best.
§  Allows 24-30 day rest period.
•  Place water within 400-600 ft
of all parts of paddock.
•  Isolate shade, mineral feeder,
and water from one another.
§  Place shade away from paddock
entrance.
Free
version of Google Earth:
•  Calculates
fence line lengths
•  Water
line lengths
Soil Type and Paddock
Mapping
•  USDA – NRCS’s Web Soil Survey
# "
!$
!
http://websoilsurvey.nrcs.usda.gov/app/
# #
Use
NRCS Web Soil Survey:
•  Calculate
acreages
•  Delineate
soil types
Dr. Dennis Hancock
Extension Forage Agronomist
2013 Georgia Grazing School:
Optimizing the size, number, and layout of your paddocks
Topo Maps and Soils Maps in
Google Earth
Soil Assessment in the Field
•  To add a topo layer, download the USGS Topo
Map Layer and open it with Google Earth.
§  http://www.gearthblog.com/kmfiles/topomaps.kmz
§  After the layer is installed you can zoom into an area
see topo maps of that region.
•  To add a soils map layer, download the
SoilWeb’s Google Earth Interface and open it
with Google Earth.
§  http://casoilresource.lawr.ucdavis.edu/soil_web/kml/
SoilWeb.kmz
§  Other such tools from SoilWeb:
http://casoilresource.lawr.ucdavis.edu/drupal/
http://itunes.apple.com/us/app/soilweb-for-the-iphone/id354911787?mt=8
Comprehensive Pasture
Management
Resources
Resources
Grass Productivity – Andre Voisin, 1959.
On Google Books or available for purchase
Dr. Dennis Hancock
Extension Forage Agronomist