evaluation of processed and preserved feeds and forages

1. SUBMITTED TO
DR.M.VENKATESWARLU
PROFESSOR
SUBMITTED BY
M.VISHNU PRASAD
RVM/16-54
ANN-604
FEED CONSERVATION,STORAGE AND QUALITY CONTROL
EVALUATION OF PROCESSED AND
PRESERVED FEEDS AND FORAGES

2. *Feed evaluation
Measuring amounts of feed constituents or
available nutrients in feeds and forages
Therefore give animals enough feed to meet
nutrient requirements and choose cost effective
feedstuffs.

3. OBJECTIVES
*Understanding of methods used to determine nutrient
composition of feeds
*Knowledge of sample collection methods
*Identify and communicate how feed samples are reported
*Comprehension of how feed stuff digestibility is
determined
*Understand various energy measurements and how they
are used
*Physical and economical evaluation of feeds

4. * Preservation technology can minimize losses, but cannot
eliminate them.
*Two basic measures:
*To prevent the activity of the enzymes present in the
product.
*To protect the product from "external deterioration factors"
such as bacteria, molds, yeasts, insects, rodents, etc.
Preserved feeds and forages

5. *Enzymes
*many of the enzymes found in food cause decomposition,
e.g., protease decomposes proteins, amylase decomposes
starch, lipase decomposes fats, and respiration enzymes
decompose sugars, etc.
* The effect of enzymes is preservation is negative.

6. *Drying
*changes the osmotic pressure and water activity,
suppresses enzyme activity and protects the product
against attack by bacteria, yeasts and moulds.
Examples; grains, seeds, hay, straw, etc.
*Salting
*changes the osmotic pressure, suppresses enzyme
activity and protects the product against attack by
bacteria, yeasts and moulds.
Examples; include fish and meat.
Food preservation methods
Based on various technologies for eliminating enzyme
activity

7. *Sweetening
*changes the osmotic pressure, suppresses enzyme activity and
protects the product against attack by bacteria, yeasts and
moulds. Examples; honey, sugar, molasses, jam/jelly making,
etc.
*Freezing
*reduces enzyme and microorganism activities. Examples; fish,
meat, vegetables, etc
*Radiation
*radioactivity and microwaves - this suppresses enzyme activity.
The products will remain good as long as they are not
contaminated again.
*Changing the pH
*As in pickling and ensiling - this protects the products as long as
the pH remains low.

8. Four main motivations for preserving forage:
*insufficient supply of forage.
*factors are drought, flood, excessively cold or hot weather, and
damage by diseases, insects, rodents and other pests.
*Easy cultivation There are seasons or conditions in which
cultivation of crops is easier, more successful, or more
economical.
*Suitability to area not every area is suitable for all crops, with
respect to climatic and other conditions;
*Keeping stocks A modern farm must always maintain a reserve
supply of feed

9. *Forage preservation methods:
*Silage
*Haylage

10. *
1. Alter physical form
2. Alter particle size
3. Prevent spoilage
4. Isolate particular portion of plant
5. Improve palatability
6. Inactivate toxins or anti-nutritional
factors
7. Easy of handling
8. Increase digestibility
Processing of feed and forages

11. *
Dry processing Wet processing
Grinding
Dry rolling
Popping
Extruding
Micronizing
roasting
Soaking
Steam rolling
Steam processing &
flaking
Pressure cooking
Exploding
Pelleting
reconstitution
Processing methods

12. *
Dry processing Wet processing
Grinding
Baling
Field chopping
Pelleting
Cubing
Dehydration
Green chopped
soaking

13. *
Key to reliable feed nutrient evaluation is representative
sample
IDENTIFICATION
thoroughly identify the feed tested
SAMPLING
GRAINS/MIXED FEEDS
Sacked feeds-5 to 7 random samples each containing a
hand full material

14. bulk feeds-12 to 15 samples,widely seperate locations for
sampling(while delivered or fed, if possble)
mix sample in a clean pail, make sure feed doesn’t seperate
Hay
use a core sampler
take a 12-15” core sample that will include stem and leaves
12-15 samples are needed to be accurate

15. *Haylage or silage
 upright silos-collect several small samples, mix
together for one composite
 pit/bunker silos-4-5 samples, do not collect spoiled
material, do not collect with in 12-18” from edge
 Freeze if you are collecting over multiple days

16. *Hay quality can differ widely even within a single species
grown in the same locality.
*The variation largely is due to a lack of understanding of good
haymaking fundamentals
*farmers tend to give less attention to hay crops than to corn,
soybeans, small grains, and other crops.
*Unfortunately, chemical analysis is not always feasible or cost
effective.
*routine chemical analysis does not reveal defects such as
dust, musty odour, mould, foreign material, and leaf
shattering.
Evaluating Hay

17. *Hay Quality Factors
*Hay quality really means feed value and should be
evaluated accordingly. The factors known to influence hay
quality and animal performance include the following:
*1) stage of maturity at harvest,
*2) leafiness,
*3) colour,
*4) foreign material,
*5) odour and condition.

18. *Stage of Maturity
*plant’s stage of development at the time it is
harvested.
*Determining the maturity of legumes and grasses is
easy before harvesting but becomes more difficult
after cutting and baling.
* Weathering or sun bleaching after cutting or the
delay of normal development of legume flowers
due to cool, cloudy weather

19. *Leafiness
*the ratio of leaves to stems
*an excellent indicator of hay quality.
*in legumes is particularly critical because legumes
lose their leaves during curing and handling more
readily than grasses.
*It is extremely important to high quality feed given
about 60% of the (TDN), 70% of the protein, and 90%
of the vitamins are found in the leaves.
* A high percentage of leaves also indicates good
harvest and handling methods.

20. *Colour
*The most desirable hay colour is the bright green of the
immature crop in the field.
* This colour usually indicates that the hay was rapidly
and properly cured, with no damage from rain, moulds,
or overheating during storage.
*A fresh aroma, freedom from must or mould, and a
relatively high carotene content add to its palatability
and feed value.

21.  Rain damage.
 Hay that has been exposed to rain or to heavy dews or fog
has a characteristic dark brown or black appearance.
 Heating damage.
 Brown hay indicates heating from microbial (mould) growth
because the hay was not sufficiently dry when it was baled.
 Extensive heating, as with brown hay, results in
considerable loss of dry matter, digestible protein, and
energy and destroys much of the carotene and other
vitamins.

22.  Foreign Materials
 Foreign materials can be divided into injurious and noninjurious
categories.
 Injurious foreign material is material that will harm the animal if
eaten. This includes poisonous plants and matter such as wire or
nails.
 Noninjurious foreign material is matter that is commonly wasted in
feeding operations but is not harmful to livestock if eaten. This
includes weeds, grain straw, cornstalks, stubble, chaff, and sticks.

23.  Odour and Condition
 The smell of new hay is the standard by which hay odour is
judged.
 mustiness, or a putrefied (rotten) odour result from weather
damage or insufficient drying before baling and indicate lower
quality hay.
 Odour problems usually result in lower acceptability by
livestock.

24. Hays of Various Qualities

25. *Sensory evaluation
*nose and eyes can tell a lot about silage quality or problems.
*First
*bunker face it should be very smooth and straight. This
minimizes oxygen exposure to the silage.
*Bunker silos with irregular and uneven faces have greater
surface area exposed to oxygen and therefore a greater
chance at increased microbial activity.
evaluation of silage

26. *Second
*the colour of the silage can indicate potential fermentation
problems
* Silages with excessive acetic acid will have a yellowish .
* Those with high butyrate will have a slimy, greenish colour.
* Brown to black silage usually indicates heating from
fermentation and moisture damage.
*These silages have the highest potential for moulding and are
unacceptable feeds.
*White coloration of silage is usually indicative of secondary
mould growth.

27. *Third
*silage odours can also help you evaluate fermentation.
Normal silage has minimal odour because of the lactic
acid.
*Clostridial fermentation results in a rancid-butter smell.
*No silage should have a musty, mildew or rotten smell
due to moulding.
* Remember if the smell of the silage is really unpleasant
, most likely it will be refused by cattle or at least
reduce intake.

28. ODOR COLOR CAUSE
Vinegar Yellowish
Acetic acid production
(Bacillus)
Alcohol Normal Ethanol production (Yeast)
Sharp sweet Normal Propionic acid production
Rancid butter Greenish
Butyric acid production
(Clostridium)
Caramel/Tobacco Dark brown to black
High temperature, Heat
damaged
eventually a good, clean-
smelling
Yellowish or brownish or
golden yellow
lactic acid production
Odor and color evaluation of silages.

29. Physical evaluation
Visual Appraisal
such as sight, smell and feel, but they are important
tools for evaluating forages and feeds. Colour, leaf
content, stem texture, maturity, contamination
from weeds, moulds or soil, and observations on
palatability are examples of useful visual
determinations.
General evaluation of feeds and forages

30. *FEED MICROSCOPY
basic and major tool to identify feed
ingredients,adulterants and contaminants of feeds
qualitative feed microscopy- identifies and
evaluates ingredients and foreign materials
quantitative microscopy-proportioned
measurement of each ingredient in finished feeds
or contaminants and adulterants in ingredients

31. Proximate Analysis
• Dry matter content (100 percent minus moisture
content)
• Crude protein (total nitrogen is measured)
• Ether extract (lipids and fats)
• Ash (mineral content)
• Crude fiber (cellulose and some lignin)
Using the above analysis, the proximate system
estimates the following:
• Nitrogen free extract (sugars, starch and some of
the hemicellulose and lignin)
• Total digestible energy (estimate of digestibility)
Chemical evaluvation

32.  While the proximate system has some limitations for
the analysis of forages, portions of it are widely used
today.
 Most typical forage analyses use the dry matter and
crude protein
 procedures from the proximate system to determine
percent dry matter and percent crude protein.
 Ash (total mineral content) and ether extract are
not commonly determined in a typical forage
analysis.
 The original crude fiber analysis has been replaced
with the newer detergent analysis.

33. Dry Matter Determination
It is important because all animal requirements are
made on a dry matter basis. It would be impossible
to compare different forages without using the
percent dry matter as a base line.
 Dry matter is also very important as the moisture
content will give clues as to how a forage will
preserve when stored by baling or ensiling.

34. Protein Analysis
 In legumes protein is the primary nutrient
 It is important to understand what protein analysis
tells about the quantity and quality of the protein
present in the forage and feed.
When a laboratory uses wet chemistry, crude protein
will most likely be measured by the standard Kjeldahl
procedure.
This measures total nitrogen which is then multiplied
by 6.25 to arrive at the crude protein value for the
forage.
 The 6.25 figure is used because most forages have
about 16% nitrogen in the protein (100 divided by 16
=6.25).

35.  True plant protein is roughly 70 percent of the
protein in fresh forages, 60 percent of the total in
hay forage and lower than 60 percent in
fermented forages.
 Ruminant animals are able to utilize a portion of
both types of protein.
 Many laboratories report a digestible protein
value. a calculated number, such as 70percent of
the crude protein

36.  If heat damage is suspected, an analysis for bound
protein or unavailable or insoluble protein
 the bound protein as ADF-CP is unavailable or
insoluble crude protein.
 a portion of the crude protein in forages that is
unavailable, the percentage of which will increase if
heating has occurred.
 If the bound or insoluble protein is greater than 12%of
the crude protein, there has been enough heating to
reduce protein digestibility.
 If the bound protein is over 15%, there has been
extensive heating in the forage.

37. Crude Fiber Analysis
 uses alkali and acid treatments to isolate the
cell wall residue (crude fiber) that represents
undigestible portions of the forage.
 It was later learned that ruminants could digest
a portion of the crude fiber.
Crud fat or ether exract
*can be determined by using soxhlet extraction
assembly *ether can be used as a solvent which
extracts all the true fats as well as other
substances soluble in ether

38. Detergent or Van Soest Method of Cell Wall
Determination
in the 1960s by Peter Van Soest this system was
developed because it was determined the crude
fiber system did not differentiate the components
of the cell wall well enough to generate accurate
energy estimates over a wide range of forages
species and maturities.
 The crude fiber system was criticized for often
underestimating good quality forages and
overestimating poor quality forages.

39. The forage sample is boiled in a special detergent
at a neutral pH of 7.0.The material is then
filtered.
The soluble portion contains these highly
digestible cell
contents:
• sugars
• starch
• pectins
• lipids (fat)
• soluble carbohydrates
• protein
• non-protein nitrogen
• water soluble vitamins and minerals

40. Neutral Detergent Fiber (NDF) and Acid Detergent Fiber
(ADF)
 The insoluble portion of the forage (neutral detergent
fiber) contains the cellulose, hemicellulose, lignin and
silica.
 It is commonly referred to as the cell wall fraction.
 as the NDF in forages increases, animals will be able to
consume less forage.
 NDF increases with the advancing maturity of forages
 The fraction of the forage cell wall that is most
commonly isolated and reported is the acid detergent
fiber (ADF).

41.  ADF is the portion of the forage that remains
after treatment with a detergent under acid
conditions.
 It includes the cellulose, lignin and silica
 ADF is important because it has been shown to
be negatively correlated with how digestible a
forage may be when fed.
 As the ADF increases, the forage becomes less
digestible.
 ADF is sometimes misinterpreted as indicating
the acid content of fermented forages.

42. Fractions of feed dry matter

46. Mineral Analysis
The minerals typically determined are calcium and
phosphorus.
atomic absorption and colorimetric procedures are most
commonly used to determine the mineral content of the
forage.

47. Near Infrared Reflectance Spectroscopy (NIRS)
Analysis
 It is a rapid and low-cost computerized method to
analyze forage and grain crops for their nutritive
value.
 Instead of using chemicals, as in conventional
methods, to determine protein, fiber, energy and
mineral content,

48. This method of analysis involves the drying and
grinding of samples which are then exposed to
infrared light in a spectrophotometer.
The reflected infrared radiation is converted to
electrical energy and fed to a computer for
interpretation.
 Each major organic component of forages (and
grain) will absorb and reflect near-infrared light
differently.
By measuring these different reflectance
characteristics, the NIRS unit and a computer
determine the quantity of these components in
the feed.

49. The NIRS method of determining forage nutritional
content is very rapid (25 times faster than
conventional laboratory procedures) and less
expensive than wet chemistry methods.
Accuracy depends on good sample collection,
storage and consistent drying, grinding and mixing
of samples prior to analysis.
Without proper calibration, the NIRS analysis can
have serious error.

50.  The typical forage analysis generated with NIRS is
similar to that using proximate and detergent
analysis.
 NIRS typically reports bound protein, available
crude protein, potassium and magnesium values.

51. In Vitro and In Vivo Disappearance Evaluation
 In vivo (in animal) and in vitro (in glass or in test tube)
procedures are seldom used for farm forage analysis.
 dry matter disappearance in a specific period of time is
measured and this value will indicate how digestible a
forage
 may be the term in situ (in bag) may be used to describe
the procedure where small nylon bags containing
samples of forage are placed in the rumen of live
animals consuming similar diets to the forage being
evaluated.
 This is done through a sealed external opening into the
rumen of an animal, called a canula.

52. In vitro is usually a two-step procedure done in test
tubes.
 First the forage sample is digested using rumen
fluid from a donor animal to simulate rumen
digestion.
 The sample is then digested in an enzyme
solution to simulate digestion in the small
intestine.
 Both in situ and in vitro are excellent
techniques for forage evaluation when more
expensive and time consuming digestion or
feeding trials are not possible.

53.  Digestion trials are an excellent way to evaluate
forages or other feeds for nutrient availability.
 In this procedure, the forage is fed to several
animals.
 The amount of forage fed and faeces produced in a
10 to 14 day period is recorded and sampled for
analysis.
 Because an analysis can be done on both the feed
and the faeces, it is possible to determine the
digestibility for each nutrient in the feed.

54. Digestible nutrients (TDN).
The actual formula is:
% digestible crude protein +
% digestible crude fiber +
% digestible starch and sugars +
% digestible fats x 2.25 = % TDN
The fats are multiplied by 2.25 because they
contain that much more energy per unit weight.
An estimate of digestibility can then be
calculated.
((dry matter intake - dry matter in feces) ÷ dry
matter intake) x 100 = apparent dry matter
digestibility

55. Conclusion;
 qualitative characterization of a forage or feed is the
critical first step in the process of evaluating forage and
feed quality.
 Laboratory methods for evaluating feeds are developing
a newer techniques become available and feed evaluation
system become more sophisticated
 More strategic and applied research is required to
further develop the science and application of tropical
feed evaluation and laboratory techniques.

56. *
* Principals of food/feed preservation
* ftic.co.il/Forage%20Manual%20Principals-en.php
* Assessing quality and safety of animal feeds
* www.fao.org/docrep/007/y5159e/y5159e03.htm
* Search Results
* [PDF]Forage Nutrition for Ruminants - UC Davis Plant Sciences
* www.plantsciences.ucdavis.edu/.../Forage%20Nutrition%20for%20Rumin
ants.NDSU....
*
Principles of animal nutrition and feed technology D.V.REDDY