Forage seed production is important to establish new pastures and improve existing ones. Quality seed is needed that is well-suited to the local environment and livestock needs. Forage development programs should include local seed production for long-term sustainability. The main objectives of a local seed production program are to meet the seed needs of the forage development initiative. Procedures for forage seed production include initially importing seed to establish programs. Small trials of untested species and cultivars should be conducted on farms. Contract seed production, where farmers grow or collect seed through agreements, has been the most successful method in Ethiopia.

1. Chapter 6
Forage Yield and Quality
What is forage quality?
– The capacity of a forage to supply
animal nutrient requirements.
– Includes characteristics that make
forage valuable to animals
• Characteristics affecting
consumption and utilization. (Will
the animal consume it and be able
to digest it?)
– Palatability (acceptability)
– Chemical composition
– Digestibility of the
nutrients
• Capacity to supply animal
requirements. (Once digested, will
the forage provide the needed
nutrients for growth and health?)
Ruminants and
other herbivores
can utilize high-fiber
feedstuffs because
their digestive
tracts are inhabited
by microbes that
can break down
structural
carbohydrates.

2. What is forage quality?
...it encompasses nutritive value and
voluntary intake and effects of
antiquality constituents
 Nutritive value: nutrient concentration,
digestibility, and end-products.
 Voluntary intake: quantity of dry matter
animals will consume when available
in unrestricted supply (ad libitum).
• Limited by cell wall concentration.
• Energy requirements of the animal is
important.
• Heat stress reduces intake.
 Antiquality constituents: chemical
compounds that have negative effects
on intake or produce negative
responses in animals consuming the
forage.

3. Forage composition has two primary divisions:
1. Cell contents – digested rapidly and completely.
2. Cell walls – digested slowly and partially.
1. Cell contents
 Non-structural carbohydrates
 sugars, starches, fructosans
 Protein and NPN
 60-80% protein; amino acids,
nitrate
 Minerals
 P, S, K, Mg, Ca, etc.
2. Cell wall
 Structural carbohydrates
 cellulose and hemicellulose
 Lignin and other phenolics
 Indigestible, 3-20% DW
 Cutin
 waxy outer covering
 Silica

4.  Plant species and mixtures
 Legumes vs. grasses / mixtures
• Legumes are higher in protein and have
faster rates of fiber digestion.
 Cool-season vs. warm season
• Cool season grasses are more digestible
due to anatomy differences.
 Breeding can improve quality and maturity
differences can be large.
 Temperature
 Plants grown at high temperatures produce
lower quality forage due to lignification.
 Maturity stage
 Maturity stage at harvest is the most important
factor determining forage quality of any
species.
 Forage quality declines as maturity
advances.
2. Factors affecting forage quality

5. Maturity stage:
Forage quality declines rapidly with advancing maturity.
40
45
50
55
60
65
20 30 40 50 60 70 80 90
Leaf
Percent
(%
of
DM)
Days
• Leaf-to-stem
ratio
 Leaves are
higher in
quality than
stems.

6. Factors affecting forage quality
• Fertilization
 Most important for grasses; N fertilization increases yield and crude
protein (%N*6.25).
• Harvesting and storage techniques
 Field losses include rain damage, leaf loss, and plant respiration.
 Storage losses to uncovered bales can be 40%.
• Foreign material
 Dirt, weeds, wire and straw are all considered foreign material.
 High quality hay will have little to no foreign material.
• Antiquality factors
 High quality forages should be free of antiquality factors that
discourage animal consumption.
 Can be chemical (toxins) or physical (thorns).
Managing for high quality:
• Choose adapted species.
• Include legumes.
• Fertilize and control pests.
• Harvest at early maturity stage.
• Protect from deterioration.
• Allow adequate re-growth time.

7. 3. List and define the components of forage.
 Nutrients for livestock production include:
– Carbohydrates
– Fats
– Proteins
– Vitamins
– Minerals
– Water

8.  Carbohydrate and Fat  Energy (calories)
– Energy = the potential to do work
– Can be measured as calories, in the U.S., and the joule, in international areas
– One calorie is the heat required to raise the temperature of one gram of water
from 16.5 ° to 17.5 ° C (1 calorie = 4.184 joules)
 Livestock diets required a lot of energy and since one calorie is so small,
kilocalorie and megacalorie are often used
1 kilocalorie = 1,000 calories
1 Mcal = 1,000 kcal or 1,000,000 calories
 Energy (cont.)
– Can be measured as total or gross energy (GE)
 Often the energy available for work is measured as digestible energy (DE)
– Calculated after the energy lost in feces is subtracted
– Can be expressed as an amount (kcal/g) or a % of GE
– Carbohydrates have 4.2 kcal/g of energy, fat has 9.4 kcal/g and protein
has 5.6 kcal/g
– Total digestible nutrients (TDN) can be calculated by total the digestible
crude protein, digestible carbohydrates and 2.25 times digestible crude fat.
 TDN is a commonly used measurement but not recommended as the best
for ruminant animals because of microorganisms in the rumen

9.  Energy (cont.)
– Metabolizable energy (ME)
 Account for the 3-5% of energy that is lost in urine and 3-10% of the
energy that is metabolized to methane that escapes from the rumen as
eructated (belched) gases.
 Subtracting these losses from the DE leaves the ME
 DE is converted to ME by multiplying DE by 0.82
– Net energy (NE)
 The amount of energy available to the animal for maintaining bodily
functions (Nem) and producing new products (NEp) after some energy is
used to metabolize the consumed food
– New products also include growth (NEg), milk (NEl), and
reproduction (NEy)
 Protein
– Complex combinations of amino acids
 Amino acids are the building blocks of all cells and tissues including the
blood, skeleton, vital organs, brain, muscles and skin
– Necessary for synthetic processes essential to life
– Forages are tested for crude protein, available protein, unavailable protein,
adjusted crude protein and soluble protein
 Crude protein (CP) is the most often used expression

10.  Minerals
– 15 + minerals are categorized as either macrominerals or microminerals
 Macrominerals include: calcium, magnesium, phophorus, potassium, sodium,
chlorine and sulfur
 Microminerals include: chromium, cobalt, copper, iodine, iron, manganese,
molybdenum, nickel, selenium, zinc, arsenic, boron, lead, silicon and vanadium
– Minerals are listed as a percentage of the total sample taken for testing or in parts per
million (PPM) for some minerals
– Since certain minerals may be toxic to livestock if found in large quantities and
deficiencies may result in declining animal health and performance, mineral content
should be considered in the quality of the forage
 Vitamins
– Vital for animals for various functions and needed to efficiently utilize other nutrients
– A, D, E, K, B12, Thiamin, Niacin, and Choline are needed
– Supplements can be used but add to the expense of feed
 Water
– Much of the water consumed by livestock is within feedstuffs
– Vital for body temperature regulation, growth, reproduction, lactation, digestion,
metabolism, excretion, and many other functions
– Amount needed will vary according to animal size, growth stage, location and type of
feed
– Forages are tested for the dry mater content and moisture content to aid in determining
quality

11. 4. Describe methods for determining quality.
 Forage quality can be determined by many
ways but the three main methods are:
1. Organoleptic (sensory) observation
2. Chemical composition
3. Feed trial evaluations

12. 1. Organoleptic (sensory)
observation
– Using the sense organs
(eyes, nose, taste, ears, touch)
to evaluate forage
– Factors to consider include:
 Species
 Maturity stage
 Leafiness
 Color
 Odor and condition
 Foreign material

13. Nitrogen analysis technique developed in
1883 by Johan Kjeldahl, a Danish chemist.
2. Chemical composition (laboratory analysis)
– More accurately determines quality of forage
 Helps livestock manager determine how
much forage and supplement are needed
for a particular animal and production goal
 Allows for better rationing
– When forage is sampled, sample must be
representative of what is being predicted
Laboratory analysis: historical
 Proximate analysis system
– Dry matter (DM) – moisture free weight
– Crude protein (CP) – %N*6.25
(because plant protein is 16% N; 100/16=6.25)
– Ether extract (EE) – lipids and pigments
– Crude fiber (CF) – weak acid and weak base
extraction
– Ash – mineral content after combustion at 1100F
– Nitrogen free extract (NFE) – by difference
(100-CP+EE+CF+Ash)

14. Laboratory analysis: Current
 Detergent analysis system (Peter Van Soest)
– Cell walls
– Cell contents
This detergent analysis system more
accurately predicts what nutrients the
animals can use by distinguishing between
cell walls and cell contents.
4. Describe methods for determining quality.

15. Laboratory analysis: Current
 Detergent analysis system (Peter Van Soest)
– Cell walls
– Cell contents
This detergent analysis system more accurately predicts what nutrients the
animals can use by distinguishing between cell walls and cell contents.

16. Laboratory analysis: NDF
 Neutral Detergent Fiber
– Determined when a sample is extracted with a
neutral detergent solution
– Cell contents are largely soluble and the cell
wall components are insoluble
– NDF value predicts dry matter intake (DMI)
[because …. a high NDF means the animal
feels full longer because certain components
are taking longer to be digested, and … if the
animal feels full, it eats less]
– Corn grain is ~ 10% NDF; nearly 90%
digestible
– Straw with an NDF of ~ 80%; only 20%
digestible
– Dry matter intake decreases with increasing
NDF
(negatively correlated)

17. Laboratory analysis: ADF
 Acid Detergent Fiber
– Sample is extracted with a sulfuric acid detergent solution
– Cell walls are partially digestible with cellulase
– ADF value predicts digestible dry matter (DDM)
– Corn grain is ~ 3% ADF
– Dairy quality alfalfa is < 30% ADF
– Late maturity grass hay and straws may be > 50% ADF
– Digestible Dry Matter decreases with increasing ADF (negatively
correlated)

18. 3. Feed Trial Evaluations
– Ultimate evaluation
 In vivo and in vitro digestibility measures
 Feed – Fecal = Digestible
– Costly and require proper sampling but are
faster and more specific
Values will be reported for:
 Dry matter / moisture: for “as fed” and
“dry matter basis”
 % Nitrogen
(crude protein = %N * 6.25)
 Fiber analyses
 NDF and ADF
 Mineral analyses
 Ca, P, Mg, K, S
 Calculated values
 TDN, NEm, Neg, NEl, RFV
Interpreting forage analysis reports

19. Relative feed value (RFV)
What is it, why is it, and how is it
calculated?
• RFV was developed to provide a
single value for comparing forages
• Higher RFV values indicate higher
quality forage
(in contrast to NDF and ADF
numbers being inversely correlated
with quality)
• RFV is calculated as follows:
RFV = (DDM * DMI) / 1.29
where DDM = DM digestibility
(%)
DMI = voluntary DM intake (%
of BW)
DDM = 88.9 – (0.779 * ADF)
DMI = 120 / NDF

20. Antiquality factors affecting animal health.
 Antiquality characteristics are traits that make plants undesirable for consumption and can be physical,
like thorns or secondary metabolites, unpleasant odors or tastes.
 Antiquality characteristics include things that contribute to:
– Illnesses
– Poor animal gains
– Low consumption
– Reproductive difficulties
 Livestock will often not select plants with physical antiquality factors such as thorns, molds, dust or
weeds if there is another choice available.
– These unpalatable traits reduce intake and may decrease microbial activity in the rumen, reducing
digestibility.
 Most antiquality factors are chemically based.
– This results in undesirable tastes and odors which influence selection and palatability by the animal.
– Some cannot be detected by taste or smell and are toxic leading to health problems.
Common antiquality components include:
– Lignin: reduces digestibility; late maturity forage has more lignin, less palatable
– Tannins: reduce palatability
– Saponins: can cause bloat
– Coumarin (sweet clover): anticoagulant
– Flavonoids: can lead to reproductive failures
– Nitrates: nitrate poisoning
– Endophytes (perennial ryegrass and tall fescue): toxic ergoalkaloids (Lolitrim b and
ergovaline)
– Alkaloids: reduce palatability

21. Summary of Forage Quality
 High-quality forage fed to livestock in sufficient quantities will result in
improved animal performance.
 Forage quality is the most significant factor affecting how much forage
and supplement will be required each day.
 Forage quality can be measured several ways including visual
(organoleptic) methods, chemical analysis, and feeding trials.
 Stage of maturity has the greatest influence on forage quality.
 Forage quality is most greatly influenced by how it is managed.
 Use approved methods for sampling and a NFTA certified laboratory for
testing.
• The primary purpose of growing forage crops is to feed animals. Factors
affecting intake and digestibility are of central importance in forage
management.
• Cell walls and cell contents are affected by species selection, fertilization,
and harvest timing.
• Maintaining forage quality at time of harvest is a function of harvesting
techniques and storage conditions.

22. 7.1. Aim and Need of forage seed production
 The production of forage to overcome livestock feed shortages is
dependent on the availability of reliable supplies of quality seed at the
time of planting.
 Sowing a new pasture or improving an existing natural pasture requires a
reliable source of seed or vegetative material of species recommended and
adapted for the area.
 Availability of quality seed or vegetative material that is suited to farmers’
needs for livestock production. Farmers’ needs are variable depending on the
environment, type and class of grazing animal and the animal product
required.
 Forage development programs need to include local seed production to
ensure their long-term sustainability and economic viability. Because
of the wide range of agro-ecological zones and farming systems in
Ethiopia, many species are required, but local production of seed for
the key species can be initiated very early in the forage program.
 The principal objective of a local seed production program should be
to meet the forage seed needs of a forage development program.
Chapter 7
7. Pasture Establishment and Seed Production

23. 7.2. Procedures of forage seed production
1. Importation of Initial Seed
 The first years of an improved forage production program will
normally need to be established with imported seed.
 The cost of seed is small compared to the benefits of rapid and
widespread implementation of improved forage production. Small
quantities of a very wide range of species and cultivars should be
imported along with larger quantities of proven species or
cultivars to initiate forage production programs.
 Regional or small scale trials should be conducted with untried
species and cultivars to assess their suitability for wider use.
 Wherever possible these trials should be conducted in farmers'
fields but careful planning and supervision of the trials are
important to protect them from grazing and to ensure that small
quantities of seed are effectively used.

24. 2. Contract Seed Production
 The most successful method of producing forage and browse seeds in Ethiopia has
been to contract farmers to grow or collect seed.
 Contract seed production involves establishing a contractual agreement between a
farmer and the seed purchaser – usually the Ministry of Agriculture, but sometimes a
seed trader.
 The seed contract is a legally binding agreement between the purchaser (a project or
Ministry or trader) and the farmer or a group of farmers. Both the purchaser and the
producer must make certain commitments under the seed contract.
a. The Purchaser Must:
 Provide seed for initial sowing.
 Provide close supervision and technical backup or the seed plots.
 Purchase the seed for cash at an agreed price for certain quality at a specified
time.
b. The Producer Must:
 Produce seed to an agreed quality.
 Sow, manage and harvest the crop.
 Clean the seed after harvest and deliver it at a specified time.
 Contract prices are based on estimated yield, production costs, the market for seed
(or program requirements), and the cost of imported seed. Local seed prices will
normally be significantly less than imported seed prices because they exclude
shipping or airfreight costs

25. 7.3. Management of Grasses and Legumes for Optimum Seed
Production
1. Site Selection:
 The most suitable sites for forage and browse seed production should
be/have:
 An adequate growing season to support good seed set and
maturation;
 Free from frost; even, sunny conditions during flowering to promote
flower opening, pollination and high rates of photosynthesis during
seed differentiation;
 Access to labour for harvesting and seed cleaning; and
 Access to markets and seed storage infrastructure.
 Weed free areas or areas that have a history of reasonably clean
cropping are preferable to weedy areas to minimize the problems of
weed competition in the seed crop.
2. Seedbed Preparation:
 Seed crops need to be established in a clean, fine and firm seedbed with
sufficient seed to ensure a strong, dense plant population, which will
compete with weeds and maximize yields.

26. 3. Seed Treatment
 Legumes seeds need to be treated to soften hard seeds, which will not
germinate without treatment.
 Browse legumes and forage legumes with less than 500,000 seeds per
kg should be treated.
 The simplest say is to boil water in a tin, remove the tin of boiling water
from the fire, and immerse a cloth bag containing the seed in the hot
water for about 10 minutes.
 The treated seed should then be rapidly cooled by spreading it out in a
thin layer. E.g. Stylos are sensitive to heat so they should only be
immersed for 3 minutes.
 Where hot water treatment of seed is impractical, scarification is
suitable alternative. The simplest way to scarify or scratch the seed
coat is to combine some seeds with sand or gravel and thoroughly mix
them together so that the gravel or sand scratches the seed.
 Legume seeds should be inoculated. When using cultivars or species
new to an area, legume seed should be inoculated with appropriate
rhizobia to ensure that they fix nitrogen.

27. Seed harvesting
• In tropical pasture seeds, the choice of harvest time is a complicated decision because
some immature seeds will always be present. Even the most closely synchronized crops
comprise inflorescences in various stages of maturity and there is further variation in
flowering time within individual inflorescences.
• Most tropical legumes flower and set seed over a long period and frequently shed seed
quickly. This makes it very difficult to judge when to harvest seed.
• For a particular crop, the period in which high yields of ripe seed can be harvested depends
on the species or cultivar involved.
• Techniques used to judge ripeness include testing for ease of seed removal; seed hardness;
and field colour.
• When most seed can be easily removed by gentle rubbing or shaking, then seed is normally
close to shedding and should be harvested. If seed rubbed in the palm of the hand is hard
and dry then it is mature and ready to harvest.
• The seed or pods of some species, for example Siratro, Rhodes Grass, tree lucerne and
Leucaena, change colour as they ripen.
• The optimum harvest time usually occurs before maximum flower density occurs.
• Hand harvesting of tropical pasture seed, particularly if labour is experienced and well
supervised, can lead to high yields of good quality seed.
• Hand harvested yields are generally higher than yields from mechanical harvesting. As an
alternative to hand picking, mature seed of both grasses and legumes can be removed from
the plant by shaking it into a basket or bag. Hand picking and shaking two or three times per
week will maximize seed yields and farmer income.
• Small seeds can be collected from threshing areas by sweeping. This technique is
particularly suitable for stylos, Wynn Cassia, and Axillaris.
7.4. Harvesting, threshing and storage condition of seeds.

28. • After harvest, seeds must be threshed, cleaned and dried ready for storage.
• Newly harvested seeds contain husks, straw, soil particles and other unwanted
seeds.
• These must be removed through the threshing and cleaning process to obtain
good quality seeds of the required cultivar.
• Seeds are often harvested at higher moisture contents than those recommended
for storage.
• Moist seeds are more susceptible to damage during cleaning because they are
relatively soft.
• Drying reduces seed moisture to a safe level for both cleaning and later storage.
• Threshing involves separating the seeds from panicles and straw and winnowing
the chaff from the seeds.
• The process of separating the seed from the chaff or pod often requires
considerable energy but sorting the seed from the straw is a relatively easy
process. This process is followed by winnowing.
• Winnowing uses wind to separate heavy and light material. It involves dropping
the material from shoulder height or higher on to a clean area on the ground with
wind blowing from behind.
• Any material that is lighter than the seed is removed and the remaining fallen
seed is hand sorted to remove imperfect seed and non-seed material. Whether by
hand or machine, winnowing is easy to handle.
Threshing and winnowing

29. Threshing methods
Seed materials can be threshed by hand or machine. The basic principles of each of these
methods are examined below.
Manual threshing:
1. Small-scale farmers employing this method often use a simple stick or flail to separate the
seed from the inflorescence and straw by beating the crop repeatedly on the floor.
2. The crop or plant parts bearing the seed may also be beaten against stones to release the
seeds.
3. Hand collection by rubbing or shaking ripe seeds into a container can provide seed of
excellent quality especially when labour is effectively supervised.
Animal-powered threshing
1. Animals are used to trample on plant parts bearing the seed.
2. Weights are added behind the animals to increase threshing productivity.
3. This method is considered relatively cheap but is slow.
Engine-powered threshing
1. Where whole undamaged straw is valuable, machines can be used to strip seed from the
panicle without damaging the straw. These can be stationary and powered by an engine or
mounted on a tractor and taken to the field.
2. This method is considered the most expensive and usually used only in large-scale
operations.
In all the techniques care must be taken to minimise physical damage which can affect
germination or allow disease infestation. In legumes, abrasion can reduce the degree of hard
seededness.

30. 7.5. Post-harvest seed management
 The overall aim of seed management is to consistently succeed in
producing a seed crop with not only a high yield of quality seed,
but also a crop, which allows efficient seed harvesting. This
essentially means having a crop of uniform age is best which can
be achieved by establishing an adequate, uniform plant
population; developing a dense cover to exclude weeds,
encouraging flowering at the same time; and ensuring that flowers
produce mature seeds.
 Regular crop inspections are important to control weed and pest
populations.
 Weeds should be hoed or pulled by hand. Weeds not only
compete with the seed crop but they also increase the risks of
contaminating forage seed with weed seed – something which
increases the work required for effective seed cleaning.

31. 1. Seed Drying and Cleaning:
 Legume seed should be dried as soon as possible after harvest to achieve a
seed moisture content of 8 to10 percent. This ensures good seed viability. Seed
can be sun dried without damage to the seed.
 Grass seeds should be heaped immediately after harvested so that they will
"sweat" to assist final maturation of the seed. Grass seed is more sensitive than
legume seed and should be dried slowly to maintain its viability.
 Sun drying is not recommended because of this grass seed can/should be dried
in the shade.
 All dried seed should be turned regularly – at least once per day – to ensure
efficient drying. Dried seed is then threshed using animals, a mortar and pestle,
or beating with sticks or flails.
 Regular inspection of the seed is essential to avoid damage to the seed.
 Threshed seed is then cleaned to remove seeds of contaminant species, soil,
chaff and poor seeds.
 Winnowing and sieving are the normal means of cleaning seed.
 Most farmers in Ethiopia are skilled at manual seed cleaning of both coarse and fine
seed, for example maize and teff.
2. Seed storage
 Once cleaned, harvested seed must be stored in a cool, dry place. The length of
life of a seed in storage depends on the environment in the seed store.

32. 7.7. Seed Distribution
• The major consideration in assessing seed marketing efficiency is
the distribution network.
• Distribution completes the process that converts the physical and
biological properties of seed produced to economic value for the
seller. Distribution needs to be considered in terms of marketing
channels and logistic functions.
• Seed passes from the producer to the user through a marketing
channel.

33. Management of Improved Pasture
Chapter 8

34. 8.1. Grazing management

35. 8.2. Grazing systems