Department of Agronomy MF-1118 Stocking Rate
Kansas State University Agricultural Experiment Station and Cooperative Extension Service
Grazing management is the art of integrating
animals, feed, and other inputs with land, labor, and
capital resources. In this publication, land includes
rangeland, tame pasture, annual forages, and crop
residues. Labor includes the owner/operator, family,
and hired help. Capital includes cash, other assets
that can be easily converted into cash, and available
credit.
The goal of grazing management is to market a
valuable product at a profit, while maintaining or
improving the productivity of grazing land resources.
Grazing management relies on several principles and
practices. Of these, stocking rate has the largest
impact on both animal performance and forage
resources. Understanding grazing management
principles is one of the keys to the ultimate profitability
of the operation.
Stocking Rate
Stocking rate is defined as the land area allocated
to each grazing animal for a specific length of time.
Stocking rate influences:
• How well the plant can recover from grazing
during the growing season
• Future forage production
• The quality of the available forage
• Animal performance
• Long-term change in species composition
Many livestock operations base their stocking
rate on tradition, the advice of their neighbors,
financial pressure, research results, or simply a best
guess. For grazed forages to remain productive,
grazing use must be matched to the individual
pasture’s carrying capacity.
Determining stocking rates requires knowledge
of forage production and grazing pressure. The
amount of forage available for harvest is affected by
climate; soil characteristics such as depth, slope, and
texture; and the extent of unproductive areas where
rocks, brush, and unpalatable species are prevalent.
Of these factors, climate has the most significant and
overriding influence on forage production. Forage
production varies between pastures and locations
within a pasture.
Grazing pressure is the ratio of forage demand to
the amount of forage available. It is usually measured in
terms of the number of animal unit months (AUM) per
acre, although it may also be measured by AUMs per
ton or pound of available forage. An animal unit (AU) is
defined as the average annual amount of forage required
for a 1,000-pound mature cow of above-average milking
ability with a calf less than 3 to 4 months old, weaned
at 400 pounds. After 4 months of age, a 400-pound calf
requires an additional 0.3 AU equivalents (AUE). Other
classes of livestock are defined in terms of AUEs. For
example, a 1,000-pound dry cow has an AUE of 0.9. A
500-pound calf has an AUE of 0.5. One AUE consumes
about 750 pounds of air dry forage per month.
Changes in the type of grazing animals, the animals’
physiological stage, and forage availability can each
cause a change in grazing pressure.
When matching grazing pressure and carrying
capacity, the goal is to devise a management system that
will optimize animal and forage production over the
long-term, rather than attempting to maximize either
factor by itself. The graphs in Figure 1 depict the
relationships between animal production and stocking
rate (Georgia — Hoveland, 1986; Virginia — Blaser, et
al., 1986; Texas — Kothmann, 1975; Wyoming — Hart,
et al., 1988). The results of these four research efforts,
designed to maintain or improve long-term forage
productivity, were essentially the same even though
they were conducted at different locations with different
forage types.
This relationship, along with long-term research in
Kansas and other Great Plains states, indicates that a
moderate grazing intensity will result in the best longterm
economic gain. The goal of moderate stocking in
this sense is to attain the best compromise between
maximum gain per animal and maximum gain per acre,
rather than to maximize either by itself.
Hart, et al. (1988) developed an economic relationship
from their Wyoming stocking rate information
(Figure 2). Maximum profits occur about midway
between the maximum animal production per acre and
the point at which individual animal performance
begins to decline. These results are similar to those
obtained by Bement (1969) on shortgrass plains in
northern Colorado.
Stocking Rate and Grazing
Management
farthest from water will usually be underused. Even
utilization of these areas is often difficult and requires
changing the grazing animals’ habits and patterns.
Animals will readily travel more than one mile to
water on level terrain, but may not travel 1/2 mile in
steep or heavily rolling terrain.
Grazing preference. Grazing
animals will often prefer certain
forages over others, and those
preferred forages are said to be more
palatable. The relative palatability of
a plant species depends on factors
such as the other species present,
stage of growth of each species, and
soil fertility level.
Grazing animals will concentrate
in areas where the plants are
most palatable. Highly palatable
species include eastern gamagrass,
big bluestem, Indiangrass, little
bluestem, and sideoats grama.
Switchgrass, blue grama, and
buffalograss will be grazed the least
when the more palatable species are
H
M
L
v.low low medium high
Forage available
Virginia — cool season tame pasture
Texas — mixed grass prairie Wyoming — shortgrass plains
Stocking rate
Production per acre or per head
Animal production
ADG, lb
Production per animal
Production per acre
Figure 1. The relationship of animal production to stocking rate based on research on different forage types.
1
2
0
Steer days per acre
90 180
Gain, lb per acre
50
25
0
Georgia — warm season tame pasture
Product per animal
Undergrazing Overgrazing
Product per land area
Grazing pressure
Optimum
A manager’s goal should be to use a moderate
stocking rate, but be prepared to change stocking rate,
remove livestock or supply additional feed during
periods of drought or other stress situations.
Uniform Utilization
Grazing animals usually
will not graze an area uniformly.
When patchy grazing occurs,
forage availability will suffer,
resulting in reduced animal
performance. Uneven grazing
patterns can occur for several
reasons:
Pasture shape, terrain,
and water location. Rough
terrain and poorly distributed
water will often result in
underused areas within a
pasture. The shape of a pasture
can also affect uniformity of
grazing. For example, in a large
“L” shaped pasture with the
water in one end, the end
Wyoming — shortgrass plains
Gain, lb per acre
0 90 180
Returns, $ per acre
ADG, lb
10
5
0
2
1
0
Steer days per acre
Production per animal
Production per acre
Return per acre
Figure 2. Economic returns maximize
midway between the peak production per
acre and the point that animal
performance begins to decline.
present. Western wheatgrass is palatable in the early
spring, but rarely grazed during late spring and summer.
In the fall, new growth again makes it palatable.
Some plants are almost never preferred when other
forage is available. These species are readily grazed
only when planted and managed as a pure stand.
Examples would be the Old World bluestems and tall
fescue.
Forbs (broadleaf plants) and browse (woody
plants) vary in palatability. Examples of highly palatable
forbs are showy partridgepea and Illinois bundleflower,
while leadplant and Russian olive are examples
of browse that are palatable only at certain times
of the season.
Seasonal nutritional needs. Forbs and shrubs
often fill nutritional needs during certain periods of the
year and may cause seasonal variations in grazing
animal distribution. Western ragweed is consumed at
higher rates in late spring and early summer because of
its high dry matter content. Warm-season grasses are
high in quality during this period, but are low in dry
matter.
Many options are available to help encourage
more uniform grazing patterns, such as salt/mineral
movement, water developments, prescribed burning,
and cross fencing. A more complete discussion of
these management options is found in KSU Extension
publication MF-515, Grazing Distribution.
Degree of Utilization
Degree of utilization refers to the proportion of the
current year’s forage production that is consumed and/
or destroyed by grazing animals. Each pasture has an
optimal degree of utilization, depending on the palatability
of the plant species, the season that the pasture
will be grazed, and the kind and class of livestock.
In determining stocking rates, only the palatable
species on the areas normally
grazed should be considered. If
unpalatable species or ungrazed
areas are included when determining
the total forage production of
the pasture, overuse of the most
palatable species may occur.
Three questions should be
answered in determining how
much available forage the palatable
plant species can produce:
How much of the herbage
should remain when the animals
are removed? As a general rule,
no more than 50 percent of the
current season’s growth should be removed during the
growing season. By leaving sufficient leaf area, the
plants can produce enough foodstuffs for current
growth and to rebuild stored food reserves. To maintain
50 percent of the leaf area, about 2/3 of the current
season’s leaf length can be removed at any one time
(Figure 3). Season of use, length of the grazing period,
time available for regrowth after grazing, condition of
the grazed plants, and current weather conditions
influence this decision.
How much of the total plant biomass is expected
to be lost during the season due to trampling,
insects, leaf drop, disease, and wildlife? These are
competing losses that must be considered in the
determination of utilization. Normally, 25 percent of
the current year’s dry matter is considered lost through
natural processes under season-long grazing.
How much of the herbage produced will be
available for harvest by livestock? Season of use and
forage nutrient content are major considerations in
animal performance.
The estimated percentage of the forage actually
harvested changes with the type of grazing method
used. Indications are that harvest efficiency increases
as the rotation interval is shortened. According to
estimates, as much as 40 percent of the forage is
harvested with intensive rotation systems. If these
estimates prove to be real and animal performance can
be maintained at or near season-long grazing values,
increased harvest efficiency will result.
Specialized intensive-management grazing programs
may increase the relative amount of forage
harvested. The more intensive systems are normally
used on irrigated, tamegrass, or annual pastures. Their
use on rangeland is recommended only when the
manager commits to the higher management
level required.
Season of Use
There is an optimum season
of use for every combination of
plant and grazing animal. Vegetative
plant growth prior to seed
stalk development is the period of
highest nutritional quality and
highest animal performance.
After seed stalk development,
forage quality declines. This is
true for both warm- and coolseason
forages, whether annual or
perennial.
Overgrazed
100
75
50
25
Proper
Figure 3. Removing 2/3 of the current
season’s leaf length (equivalent to 50%
of total leaf area) will not reduce plant
productivity.
Percent of length remaining
Take Half
Leave Half
Likewise, there is a period
during the plants’ growth cycle
when grazing pressure should be
reduced. For warm-season plants,
this period is during early vegetative
growth (late April to early
May) and again during reproductive
development (July to frost).
For cool-season plants it is in early
spring and again in the July-August
and early fall periods. During these periods, heavy
grazing should be avoided.
Reducing the leaf area of a perennial plant during
the late summer and early fall restricts its ability to
produce foodstuffs for current growth needs, stored
food reserves and root growth. Each growing season,
approximately one-third of the root system must be
replaced by new growth due to losses caused by root
pruning, shrink-swell of the soil, and diseases. Under
heavy grazing pressure, this new root growth may stop
and existing roots may die back even further.
Developing a grazing management strategy that
meets both plant and animal needs is a challenge.
Consideration should be given to using forages that
have different growing seasons. Combining a coolseason
pasture (such as smooth brome, tall fescue,
wheat, rye, and triticale) with a warm-season pasture
(such as rangeland, bermudagrass,
sudangrass, and millet) can be a
way to increase carrying capacity
and animal production. This type
of system provides a longer green
forage period. A complete economic
analysis of the alternatives
should always be made before
beginning the system. For more
information on economic budgets,
see the most recent set of KSU Extension Farm
Management Guides available at your county Extension
office
Kind and Class of Livestock
The kind and class of livestock influences stocking
rate. Different animals prefer different forages, as shown
in Table 1 (Taylor, 1981):
• Cattle diets consist primarily of grass.
• Sheep tend to prefer forbs over grass and browse.
• Goat and deer diets contain large amounts of
browse compared to cattle and sheep diets.
Because of the differences in dietary preference,
mixing kinds of livestock under certain conditions to
increase carrying capacity and production is possible.
However, the forage source must have the necessary
600 lb calf
500 lb calf
400 lb calf
300 lb calf
cow maintenance
Animal unit equivalents (AUE)
0 30 60 90 120 150 180 210 240 270 300 330 360
1.6
1.2
.8
0
Days after weaning
Weaning
Breeding
Calving
Figure 4. The relationship of weaning weight to animal unit equivalents for a 1,000-pound cow with various weaning
weights, based on NRC requirements.
Table 1. The relative proportions of
grass, forbs, and browse in the diets of
cattle, sheep, and goats.
Kind of
Forage Cattle Sheep Goats
Grass 60% 40% 20%
Forbs 20% 40% 30%
Browse 20% 20% 50%
diversity and production for the animals to meet their
dietary preferences. For example, cattle and sheep will
compete if grazed together in a predominately grass
pasture. However, they will complement each other if
grazed together in a pasture with a high proportion of
forbs and browse. Whatever the forage source, grazing
cattle and sheep together will place increased management
requirements on the operator.
The size, age, and reproductive stage of an animal
determines forage needs. As an animal’s size increases,
its forage requirements also increases. Forage requirements
also increase for rapidly growing animals.
Pregnant and lactating females have added demand for
forage from the last trimester of pregnancy through
weaning.
The AU method, defined in a previous section, is a
convenient way of adjusting stocking rate for size, age,
and reproductive status. An AUM is the amount of
forage intake for one AU for 30 days — about 750
pounds of air dry forage. Figure 4 depicts the AU
changes for a 1,000-pound cow weaning different size
calves for one year. A dry cow requires approximately
0.9 AUE of forage. By weaning time, 1.2, 1.3, 1.4, and
1.5 AUEs are required for weaning weights of 300,
400, 500, and 600 pounds respectively. A cow weighing
1,200 pounds has an AUE of 1.2 plus the requirement
for the calf.
1,200-lb cow
Above average milking
Graze 6 months
Wean calf at 400 lb
Cow is larger
0.3 AUE
NA
1.2 AUE ??6 months
= 7.2 AUM
0.3 AUE ??6 months
= 1.8 AUM
NA
9.0
9.0 AUM ??750 lb
= 6,750 lb
(500 lb + 750 lb) ??2
1,000
1,000 lb
400 lb
1,200 lb
400 lb
1,000 lb
600 lb
750 lb
500 lb
1,000-lb cow
Above-average milking
Graze 6 months
Wean calf at 400 lb
—
This 1,000-lb cow is
defined as 1.0 AUE
A 400-lb calf averages
0.3 AUE over a 6-month
period
NA
1.0 AUE ??6 months
= 6.0 AUM
0.3 AUE ??6 months
= 1.8 AUM
NA
7.8
7.8 AUM ??750 lb
= 5,850 lb
Animal
Change
AUE
Cow
Calf
Stocker
AUM
Cow
Calf
Stocker
Total AUM
*Forage
equivalent
1,000-lb cow
Above average milking
Graze 6 months
Wean calf at 600 lb
Calf is larger
1,200 lb
1,000 lb
= 1.2 AUE
1,000 lb
1,000 lb
= 1.0 AUE
(600 – 400)
1,000
0.625 AUE =
0.5 AUE =
500-lb stocker
Graze 5 months
to 750 lb
Stockers
NA
NA
NA
NA
0.625 AUE ??5 months
= 3.125 AUM
3.125
3.125 AUM ??750 lb
= 2,345 lb
NA
1.0 AUE ??6 months
= 6.0 AUM
0.5 AUE ??6 months
= 3.0 AUM
NA
9.0
9.0 AUM ??750 lb
= 6,750 lb
0.3 +
*750 lbs of air dry forage per AUM
Figure 5. Calculating the AUE of different classes of livestock.
Standard Animal
To estimate the AUE of growing cattle (stockers,
replacement heifers), the following equation can be
used:
(weight on grass + weight off grass) ??2
1,000
As an example, a 500-pound stocker going on
grass is expected to weigh 750 pounds coming off the
pasture. The AUE is 0.625. Figure 5 illustrates the
AUE calculation for four examples: a standard animal,
a cow-calf pair with a heavier cow, a cow-calf pair
with a heavier calf, and a stocker.
AUE’s can be used to adjust stocking rates for the
class of livestock being grazed. The method to use is
illustrated in Figure 6. In the example given, a 1,000-
pound cow weaning a 500-pound calf (1.4 AUE) were
grazed on a 10-acre pasture during the previous year.
Assume that this stocking rate was satisfactory. During
the current year, stocker cattle with an AUE of 0.625
(as described in Figure 5) will be grazed on that same
pasture. To adjust the stocking rate for the new class of
animal, calculate the AUM’s of grazing each will
require. The ratio between the new stocker animal
(3.125 AUM) and the previous cow-calf pair (8.4
AUM) should be determined.
This ratio is 3.125/
8.4, or 0.37. Now, instead of
one cow-calf pair per 10
acres, the 500-pound stocker
animal would require less
than half as much acreage, or
3.7 acres. If the grazing
season length is different
between the two animals,
adjust the stocking rate by
the proper ratio. Suppose the
stocker will be grazed for 5
months compared to 6
months for the cow-calf pair.
The stocking rate for the
stocker would be 5/6 of 3.7
acres, or 3.1 acres per
animal.
Literature Cited
Bement, R. E. 1969. A stocking-rate guide for beef
production on blue-grama range. J. Range Manage.
22:83-86.
Blaser, R. E., R. C. Hammes, Jr., J. P. Fontenot, H. T.
Bryant, C. E. Polan, D. D. Wolf, F. S. McClaugherty,
R. G. Kline, and J. S. Moore. 1986. Forage-animal
management systems. Virginia Agricultural Experiment
Station Bulletin 86-7. 91 pp.
Hart, R.H., M.J. Samuel, P.S. Test, and M.A. Smith.
1988. Cattle vegetation, and economic responses to
grazing systems and grazing pressure. J. Range
Manage. 41: 282-286.
Hoveland, C. S. 1986. Basics of grassland management.
In Proceedings of the four state grassland management
workshop - Warm Season Grasses: Facts and Fantasy,
July 7- 9, 1986. Ohlenbusch, P.D., editor, Kansas State
University Extension Agronomy. p 1-10.
Kothmann, M. M. 1975. Grazing management systems.
Texas Agricultural Progress 21:2:22-23 (TAP 726).
Taylor, C. A. Jr. 1981. Optimal use of range with mixtures
of livestock. pp. 166.175. In White, L. D. and L.
A. Hoermann (eds.). Proceedings of the International
Ranchers Roundup, Del Rio, TX. Texas Ag. Ext.
Serv., Uvalde, TX 434 pp.
Assumptions:
• 1993 stocking rate was correct.
• Length of time on pasture was 6 months for 1993 and will be 5 months for
1994
AUE Cow/calf = 1.4 AUE Stocker = 0.625 AUE
AUM 1.4 x 6 = 8.4 AUM 0.625 x 5 = 3.125 AUM
Stocking rate 10 acres per pair (3.125 AUM/8.4 AUM) x 10 =
3.7 acres per stocker
Figure 6. Adjusting Stocking rate for different classes of livestock
1,000 lb 750 lb
500 lb
500 lb
1993
10 acres
1994
3.7 acres
For additional information:
Tame Pasture:
Smooth Brome Production and Utilization, (C-402)
Tall Fescue Production and Utilization, (C-792)
Rangeland:
Range Grasses of Kansas, (C-567)
Management Following Wildfire, (L-514)
Grazing Distribution, (MF-515)
Rangeland Weed Management, (MF-1020)
Rangeland Brush Management, (MF-1021)
Native Hay Meadow Management, (MF-1042)
Prescribed Burning:
Prescribed Burning: Safety, (L-565)
Prescribed Burns: Planning and Conducting,
(L-664)
Prescribed Burning: A Management Tool, (L-815)
Prescribed Burning: Equipment, (L-876)
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Publications from Kansas State University are available on the World Wide Web at: http://www.oznet.ksu.edu
Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Paul D.
Ohlenbusch and Steve L. Watson, Stocking Rate and Grazing Management, Kansas State University, February 1994.
Kansas State University Agricultural Experiment Station and Cooperative Extension Service
MF-1118 February 1994
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State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Marc A. Johnson, Director.
Paul D. Ohlenbusch
Extension Specialist
Range and Pasture Management
Steve L. Watson
Extension Assistant
Agronomy