Selecting Species and Varieties for Pasture
by Edward N. Ballard, Animal Systems Educator/Effingham Center
Illinois has the climate and soil that allows the use of most
forage species presently available for humid, temperature regions of the United
States. The landscape is dominated by cool season grasses and legumes and their
mixtures. The major grasses would be tall fescue, orchardgrass, bromegrass and
timothy. Major pasture legumes would include red and white clover, annual lespedeza,
alfalfa and birdsfoot trefoil.
However, a multitude of choices may make for difficult decisions
in designing a beef pasture system. In addition, after a species is chosen,
what variety of that species should be sown. Data exist to aid in selecting
varieties, but an understanding of the value of better varieties is important
to making an informed decision.
Selecting A Species
Surely no decision about a species can be made unless there is
a clear definition of what "good" is. For this discussion a "good" forage is
one that is high in nutritive quality, is persistent, and supplies, these nutrients
cheaply. This forage should not have any "unmanageable " flaws. To decide if
one should replace the forage that you have with something else, a good question
to ask is can the new forage do the job and do it cheaper than what I presently
Species selected for use as pasture for beef cattle should be
high yielding, persistent, tolerant of the anticipated level of management and
adapted to the region and to the soil conditions in the pasture to be seeded.
To generalize, nearly all species of forage crops can be utilized for pasture,
especially if rotational grazing is practiced (Table 1). However, if pastures
are to be frequently and closely grazed then mixtures containing combinations
of Kentucky bluegrass, orchardgrass, endophyte-free tall fescue, ryegrass (perennial
and annual) and/or white clover are best. Endophyte-infected tall fescue can
be used alone or in mixtures in areas that could be used for winter pasture
or as a calving pasture in early spring.
Table 1. Suitability of several forages species for grazing
and stored feed
||Frequent, Close Grazing
|Tall Fescue, endophyte infected
|Tall Fescue, endophtye free
There are many questions that must be answered to properly select
the forage or forages that would make up the ideal or optimal system for beef
cattle. The producer must define the role, the forage production goal, the method
of use and the "utilizer", the level of management available, the soil/land
limitations, and the time limitations.
Defining The Role
There must be a clear understanding as to what role forage will
play. Will it be the primary base grass in a pasture system or will it be supplemental
forage interseeded into existing forage? Will the forage be permanent (a perennial)
or a temporary (an annual) addition to the system? What will be the primary
season of use? A species selected for fall or winter grazing will probably be
of little value during the heat of August. Likewise, productive summer forage
will likely have a relatively short (but productive) growing season compared
to a species like tall fescue.
Defining The Forage Production Goal
Ultimately, a forage system must provide enough dry matter to
carry a given set of animals for the year and also meet the desired quality
standards of the cattle that will be grazing or consuming the forage. Forages
must therefore produce enough dry mater yields per acre to meet these needs.
Also, that yield should come at such a time as can be used efficiently. The
most efficient method of forage utilization is grazing; it is estimated that
nutrients supplied by grazing cost approximately half of those supplied by stored
feeds such as hay and silage. Therefore, production during the time of animal
need would be highly desirable. Forage crops adapted to Illinois can be classified
as "cool season" or "warm season" species based on their optimum season of growth.
Tall fescue, orchardgrass, ryegrass, bluegrass, timothy, red clover, alfalfa,
and white clover are cool season forages, while bermudagrass, pearl millet,
and big bluestem are examples of warm season species. Even though species like
alfalfa and red clover are known to be more productive during mid-summer than
fescue or bluegrass, these are still cool season species whose growth slows
greatly during hot, summer months.
Defining The Method Use
A significant constraint to forage selection is the intended method
of utilization. Systems that allow for a rotation of pastures and periods of
rest/recovery from grazing offer many more forage selection options (Table 1).
On the other hand, systems that involve continuous grazing or that will suffer
excessive traffic during dormant or wet seasons have fewer options. In extreme
cases (such as winter feeding pastures) there may not even be a good permanent
solution. Often, the question of "Am I willing to rotate pastures?" must be
answered very early in the forage selection process. Not being realistic in
this area can lead to unrealized expectations, disappointment, and often-significant
financial losses. For example, alfalfa is a species that must be rotationally
grazed for maximum stand persistence and maximum economic animal performance.
As good as it is alfalfa cannot and will not persist nor give proper animal
performance when grazed continuously.
Defining The "Utilizer"
The type of cattle to be grazed and their growth stage will determine
its nutritional needs and also will help define the forage options available.
This is especially important relative to the use of existing, old fields of
tall fescue. Old fields of tall fescue are probably infected with a fungal endophyte
that spends its whole life cycle inside the plant. The presence of this endophyte
makes the plant more drought tolerant but causes reduced conception rates in
breeding stock and reduced weight gains in growing cattle. Fescue is a good
pasture base for a cowherd and can be used for stocker pasture, even if it is
infected with the endophyte. However, it is very important to understand when
the grazing animal is most sensitive to the toxic products of the fungal endophyte
and either avoids it or mange around it during these times. This management
minimizes the effect while using a cheap source of feed.
Many if not most proposed changes to a pasture system of beef
cattle will come from taking out tall fescue and replacing it with something
else. These changes should be made carefully and only after a full understanding
of the pros and cons of the new forage to be planted.
Defining The Level Of Management Available
Requirements for good forage growth and persistence may include
pasture subdivisions (to aid in good rotations), soil fertility, weed control,
rotational grazing, residual height management, fall rest for winter hardiness,
and insect control. Without pasture subdivisions and the ability to rotate pastures,
certain forages (such as alfalfa) will not be viable options. Meeting fertilizer
needs of a crop are necessary for production and persistence. Likewise, more
intensive pest management is required for some crops, such as alfalfa. While
controlling the alfalfa weevil and potato leafhopper do not always require the
use of insecticides, the economic thresholds of each one as well as the proper
cultural controls must be understood and be incorporated into the grazing plan.
The level of management available determines what can be achieved
from a forage system. In particular, the ability to maximize forage growth rates
by using a good, fast (3 to 5 days of grazing followed by 30 to 35 days of rest)
rotation will allow the maximum production of high quality forage per acre and
consequently, animal output should be equally high. Also, soil nutrient must
be managed to supply the mineral needs of the plant.
Defining The Soil Resource
What are the soil limitations of the fields in the pasture system?
Is the soil fertility and pH known on pasture fields. Acid soils and low soil-P
are severe limitations to legume production. While some legumes such as lespedeza
and birdsfoot trefoil are tolerant of acid soils and lower fertility, most are
not productive or persistent under the same conditions.
Other significant soil limitations include rooting depth, drainage,
and topography. Shallow soils are droughty and stress forage plants during hot,
dry weather. Soils that are poorly drained place stressed on the root systems
of forage crops and may be unsuitable for species like alfalfa and many of the
native warm season grasses. Severely rolling topography may remove annual crops
such as sudangrass or millet as options for forage systems because of their
inaccessibility to planting equipment. Even applying fertilizer and lime on
these fields is a challenge in some cases.
Soil fertility is an addressable limitation in forage systems,
and forage systems recycle a large portion of nutrients that plants take up
during the growing system. However, seldom can all fields be brought up to soil
test at one time. But the important point is to know what the fertility limitations
are, where they are, and to have a plan for best using these fields in the forage
Defining The Time Constraints
Making changes in a forage system take time. Making big changes
in a forage system take a lot of time. Some forages by nature can have an immediate
effect, but their effect is often short-lived. Sudangrass, pearl millet, german
millet, wheat and rye can have immediate effects but these are annuals. Perennials
like tall fescue, orchardgrass, bromegrass, and bluegrass have longer periods
Designing a forage system must allow time for perennials to become
established. Not allowing enough time for establishment is perhaps the greatest
cause of stand failure and reseeding in new seedlings of pasture. If adequate
time cannot be planned or provided for, plan or re-seeding that area every other
year or so. A species such as Italian ryegrass can be good for this purpose,
since it is a fast starter and only lives two years.
Summarizing Forage Characteristics
Summaries of many characteristics of several forage crops that
can be grown in Illinois are shown in Tables 2, and 3.
Choosing Cool Season Grasses For Grazing
Orchardgrass: Earlier maturing than bromegrass or timothy, orchardgrass
is highly palatable to grazing livestock and is a good complementary grass to
alfalfa or red clover. Orchardgrass has good regrowth after the first grazing.
Orchardgrass varieties differ greatly in maturity or date of head emergence.
Choose mid to late maturing varieties for pasture.
Tall fescue: A strong perennial that is widely adapted. The presence
of a fungal endophyte in older tall fescue enhances persistence and stress tolerance
but lowers animal performance. New varieties that are free from the endophyte
(the label will state this0 and some appear to be tolerant of heavy grazing.
Tall fescue is the best to use for fall and winter grazing (stockpiling) because
it holds its quality and palatability better than other cool season grasses.
Bromegrass: A strong perennial that matures later than tall fescue
and orchardgrass but at about the same time as timothy. Forms a tight sod that
may become less productive with age. Seed is fluffy and somewhat hard to get
to flow. Brome is highly palatable to grazing livestock.
Perennial Ryegrass: Establish rapidly, have a long growing season,
have the potential to be high yielding under favorable environments when supplied
with adequate nutrients, posses high nutrient contents, and rotational grazed.
Ryegrasses grow best on fertile, well-drained soils and are heavier users of
water and their performance is less than optimum during a drought or periods
of extended high temperatures. Ryegrasses are considered to be high quality
Timothy: A very high yielding perennial with very little regrowth
after the first harvest. Lack of summer growth makes it much less valuable in
a pasture program. Highly palatable to livestock.
Kentucky bluegrass: A strong perennial grass that forms a tight
sod. Fine bladed and highly palatable to livestock, bluegrass produces best
in spring and fall. Goes dormant during hot dry periods. Lower yielding than
tall fescue or orchardgrass.
Choosing Cool Season Legumes for Grazing
Alfalfa: Highest quality, highest yielding forage legume with
a wide variety of uses. Provides good to excellent summer growth and supports
excellent animal gains. Can be used with orchardgrass, tall fescue or brome
in pasture systems or can be grazed as a pure stand. Must be rotationally grazing
to persist, but can last 5 years or longer in well managed pasture systems.
Grazing tolerant varieties are available. Will not establish by frost seeding
onto closely grazed sod as red clover can. Interseeding into existing grass
stands require controlling grass competition by either herbicides or tillage.
Red Clover: High yielding, palatable legume with good summer production.
Less tolerant of hot weather than alfalfa, and stands last only 2 to 3 years
maximum. Better varieties have better persistence and much higher yields than
common or uncertified seed. Can be established into existing cool season grasses.
White Clover: Low growing but high quality legume. Less heat and
drought tolerant and less productive during summer than red clover. Ladino types
are giant white clovers that are higher yielding. Ladino/white is a good addition
to a pasture. Typically sown with red clover, it is very productive in spring
and fall. White clover has the highest bloat potential of all forage legumes.
White clover stands appear to persist longer than red clover and alfalfa because
it is prolific reseeder.
Birdsfoot Trefoil: A low growing legume that does not cause bloat
and must be allowed to reseed for stands to persist. Trefoil has low seeding
vigor and can often be slow to establish into existing grass. Not good for hay.
Birdsfoot trefoil sets more seed in northern locations because it flowering
response is better under long day lengths. SEED Cost is high relative to other
Forage Yield and Quality Distribution of Diverse Pasture
Results of a project conducted by Jim Gerrish, University of Missouri
Forage Research Center, Linneus, MO.
Tall Fescue Base
1) Tall fescue + 120 lb N/acre
2) Tall fescue + alfalfa
3) Tall fescue + birdsfoot trefoil
4) Tall fescue + red clover
5) Tall fescue + alfalfa + birdsfoot trefoil
6) Tall fescue + alfalfa + birdsfoot trefoil + red clover
7) Tall fescue + alfalfa + birdsfoot trefoil + red clover + orchardgrass + timothy
8) Tall fescue + smooth bromegrass + alfalfa + birdsfoot trefoil + red clover
+ orchardgrass + timothy
Smooth Bromegrass Base
9) Smooth bromegrass + 120 lb N/acre
10) Smooth bromegrass + alfalfa
11) Smooth bromegrass + birdsfoot trefoil
12) Smooth bromegrass + red clover
13) Smooth bromegrass + alfalfa + birdsfoot trefoil
14) Smooth bromegrass + alfalfa + birdsfoot trefoil + red clover
15) Smooth bromegrass + alfalfa + birdsfoot trefoil + red clover + orchardgrass
16) Smooth bromegrass + tall fescue + alfalfa + birdsfoot trefoil + red clover
+ orchardgrass + timothy + big bluestem
Results and Discussion
The mean sward height at initiation of grazing was approximately
10.5 inches which was slightly taller than our target of 8 to 10 inches (Figure
1). Rapid growth early in the season allowed some plots to exceed target height
before they could be grazed the second time. The mean dry matter availability
at initiation was slightly less than the expected target level of 2700 lb/acre
(Figure 2). The expected forage availability level was based on height:yield
relationships previously developed at FSRC. In this study, quadrats were clipped
above the thatch layer rather than at ground level as was done in the calibration
Mean rest period required to reach the target grazing height was
greater for smooth brome based pastures than for tall fescue based pastures
(Figure 3). Mean rest period was 28 days for SB pastures while only 22 days
for TF pastures. Nitrogen fertilized TF had the shortest mean rest period at
19 days. The range in length of rest period for TF + N pastures was 15 days
in May to 28 days in July-August. The longest mean rest period was required
by smooth brome + red clover at 31 days with a range from 25 days in May to
41 day in July-August. Excluding the N-fertilized TF and SB treatments, SB-based
pastures usually required about five days additional rest through the summer
months compared to TF-based pastures (Figure 4). The shorter rest periods in
August are a reflection of the summer annual grass component, primarily crabgrass,
in the swards.
While it has been fairly easy to maintain orchardgrass as a strong
component in tall fescue based pastures with rotational grazing, maintaining
smooth bromegrass in a tall fescue mixture has been much more difficult. If
a pasture is grazed using tall fescue condition as the guide for initiating
grazing, the smooth bromegrass will likely not be adequately rested. Basing
turn-in on smooth bromegrass condition may reduce palatability and quality of
the fescue component which may result in selective grazing of the brome component.
Based on these observations, pasture mixtures should not include both smooth
bromegrass and tall fescue.
As would be expected based on relative length of rest period,
mean daily growth rate for TF-based pastures was significantly greater than
SB-based pastures (Figure 5). Mean daily growth rate was similar for TF + N,
TF + BFT, and TF + BFT + RC, however, there were very notable monthly differences
among the three treatments (Figure 6). Daily growth rate of TF + N increased
very markedly following N applications in early April and mid-June and was significantly
greater than the TF + legume mixtures during April, May, and July. During June
and August, the TF-legume mixtures exhibited significantly greater daily growth.
Daily growth rate of TF + N pastures fluctuated from 33 to 89 pounds/acre/day
while the range for TF-legume mixtures was from 47 to 70 pounds/acre/day. The
range for TF + N is 270% compared to only 50% for TF + legumes. Greater flexibility
in management is required to accommodate the larger changes in daily growth
rate associated with N fertilization. Either stocking rate, size of paddock,
or amount of forage harvested as hay or silage should be adjusted more often
and to a greater extent for TF + N compared to TF + legumes. There was less
overall variance in daily growth rate among SB-based pastures than among TF-based
pastures (Figure 7).
The low relative variance in monthly mean daily growth rate is
in stark contrast to the growth curves for cool season forages that are often
presented to producers. The typical growth curves represent either unmanaged
growth or what might be expected in a hay management system. The data presented
here indicate that seasonal variance in growth distribution in managed pastures
is much less than many graziers believe. The variance occurring in mixed grass-legume
pastures is much less than that occurring in grass monocultures. The inclusion
of warm season annuals such as crabgrass and lespedeza in the mixture are also
very likely contributing to the higher level of growth observed during July
and August. The summer annual species present in these plots were not sown as
part of the mixtures but is volunteer components. Many pastures in this region
contain these or other summer annual species, which may contribute significantly
to summer carrying capacity.
Forage dry matter production is presented for the April through
mid-September period Figure 8) and also for the total growing season (Figure
9). All pastures were rested from their final grazing in mid-August or early
September and allowed to stockpile growth for winter grazing. Stockpile forage
yield was measured after the end of the growing season in early November. During
the spring-summer period, forage yield was similar for most of the pastures,
although yield distribution varied. Only six mixtures were significantly lower
yielding than the highest yielding mixture. When the stockpile phase is included,
TF + 120 N was the highest yielding pasture and it was significantly greater
than ten other treatments. Previous studies at FSRC have shown TF + RC to produce
fall stockpile yields comparable to TF + 60 lb N/acre with N applied in mid-August.
Because there was over 30 days variance, both within and among treatments, in
the beginning of the stockpiling phase in this study, that data is not presented
as a single component.
Selecting Improved Forage Varieties
The Value of Improved Forage Varieties
A forage variety should be high yielding, persistent, adapted
to Illinois, nutritious, palatable, and free from known antiquality components.
In addition, it should be tolerant of the anticipated methods of utilization
and level of management. The variety chosen should be "improved," which means
that it has bred, tested, and proven to have better traits or performance than
older varieties. The variety should be certified (denoted by a blue tag on the
bag) or at least a proprietary variety on which performance data is available.
- Henning, Jimmy C., Selecting Species and Varieties for Pasture, July,
- Gerrish, J.R., Forage Yield and Quality Distribution of Diverse Pastures
May 17, 1999.
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