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What is Forage?
Characteristics
i. Bulky
Implications on animal nutrition?
ii. High fiber
Is fiber important?
iii. Lower digestibility than grains
High quality (60 – 68%) E.g., ?
Medium quality (53 – 59%) E.g., ?
Low quality (<53%) E.g., ?
What is Forage Quality?
“The extent to which a forage has the
potential to produce a desired animal
response”
Key responses?
i. ?
ii. ?
iii. ?
Forage Quality is “Milk in the Bucket”
Ball et al, 2001. American Farm Bureau Federation Publication 1-01
Forage Quality is “Calves on the Ground”
Ball et al, 2001. American Farm Bureau Federation Publication 1-01
Forage Quality is “Pounds on The Scale”
Ball et al, 2001. American Farm Bureau Federation Publication 1-01
Forage Quality
Factors that affect animal responses?
i. Nutrient composition?
ii. Palatability?
iii. Intake?
iv. Digestibility?
v. Anti-quality factors?
Forage Quality (cont.)
Nutrient composition
i. Crude protein
ii. Carbohydrates
Fiber/NDF (cellulose, hemicellulose, lignin)
ADF (cellulose, lignin)
Non-structural CHO (starch, sugar)
iii. Other nutrients?
What Happens to NDF in the Rumen?
Gaylean and Owens, 1988. Proc. Of the Southwest Nutrition & Management Conference
Estimating DMI (as % of BW)
DMI (% of BW) = 120 ÷ %NDF
Forage Quality NDF, % DMI, % of BW
Excellent 38 3.16
42 2.86
46 2.61
50 2.40
Poor 54 2.22
ADF and Digestibility
Undersander, 2003. http://www.uwex.edu/ces/forage/
Estimating % Digestible DM
% Digestible DM = 88.9 – (ADF% × 0.779)
ADF, % DDM, %
30 65
35 61
40 58
45 54
50 50
Effects of ADF and NDF on Hay Price
Putnam et al., 2008. Irrigated Alfalfa Management in Mediterranean & Desert Zones
Forage Quality (cont.)
Factors that influence forage quality?
i. Maturity stage
Leaf-to-stem ratio
ii. Species differences
Grasses vs. Legumes
Cool-season vs. Warm-season
iii. Variety differences
iv. Growth conditions
v. Harvesting & Storage conditions
i. Maturity, Yield & Quality
http://www.gov.mb.ca/agriculture/crops/production/forages/print,annual-crops-an-excellent-way-to-increase-your-feeding-flexibility.html
Lignification and Digestibility
Lignin (% of NDF) Jung, 2012. Proceedings: Florida Ruminant Nutrition Symposium
Examples of Changes in Forage Quality with Maturity
U.S.-Canadian tables of feed composition, third edition. 1982.
ii. Grasses vs. Legumes
Grasses Legumes
Crude protein
Cell wall/fiber
Lignin
Energy
Minerals (E.g., Ca & Mg)
Bloat
Grasses
Non-leguminous, require less management
Cool-season vs. warm-season
Keyser, 2012. UT Ext. Pub. SP731-A
Cool Season Grasses
i. Orchardgrass
ii. Bromegrass
iii. Tall Fescue
iv. Ryegrass
v. Bluegrass
vi. Wheatgrass
vii. Red Canarygrass
viii. Timothy, etc.
Cool Season: Orchardgrass (cont.)
Shade tolerant perennial
Much of PNW irrigated pasture
Highly productive
Highly palatable
Compatible with alfalfa/clover mixes
Marginal winter hardiness
Cool Season: Smooth brome (cont.)
Shade tolerant, Winter hardy
Highly productive, Slow regrowth
Very palatable
High protein content
Erosion control e.g., “Lincoln”
Cool Season: Downy brome
“Cheatgrass” (Annual weed)
Drought and grazing tolerant
A lot of negatives
Outcompetes most grasses (domination)
Quick decrease in quality (maturity)
Fire prone!
Cool Season: Tall Fescue
http://www.pggwrightsonseeds.com.au/products/grasses/tallfescue/resolute/; http://www.biopix.com/trifid-bur-marigold-bidens-tripartita_photo-.aspx
Cool Season: Tall Fescue
Adapted to wide range of soil types
Highly productive
Negatives
Summer slump
Fescue toxicity (endophyte fungus)
Some varieties e.g., Alta (vs. Johnstone, Fawn)
Endophyte fungus
Produces ergot alkaloids
Ergovaline
Lysergic acid
http://stablemanagement.com/article/endophyteinfected-fescue-problems-nonpregnant-horses-14616; http://journal.frontiersin.org/article/10.3389/fchem.2014.00110/full
Ergot Alkaloids
Numerous negative effects e.g., compromised
neurological function, embryonic loss
Ergot alkaloids e.g., Lysergic acid
Biogenic amines e.g., Serotonin & Dopamine
“Fescue foot”, heat stress
Tall Fescue Toxicity (cont.)
http://thestockexchangenews.com/vet-talk-ergot-poisoning-in-cattle/; http://blog.nature.org/science/2014/02/03/bison-good-cattle-bad-a-prairie-ecologists-perspective/cows-in-pond/
Cool Season Grasses
Refer to “Improved grasses and legumes for
Idaho” for information on the following:
iv. Ryegrass
v. Bluegrass
vi. Wheatgrass
vii. Red Canarygrass
viii. Timothy
Warm Season Grasses
i. Bermudagrass
ii. Bahia
iii. Switchgrass
iv. Bluestem
v. Bluegrass
vi. Indiangrass, etc.
Warm Season Annuals
i. Sorghum
ii. Sudan grass
iii. Sorghum × Sudan hybrids
High alkaline soil tolerant
Drought tolerant
Very productive
Prussic acid & nitrate poisoning?http://www.cattletoday.com/forum/viewtopic.php?f=14&t=99322/
Prussic Acid Poisoning
Plant HCN content influenced by:
Stage of growth, Drought, Frost, etc.
HCN + Hemoglobin Cyanoglobin
(Hydrogen cyanide/Prussic Acid)
(Cyanogenic glucoside)
http://homepage.ruhr-uni-bochum.de/Markus.Piotrowski/Index.html?Research_Nitrilase.html
Nitrate Toxicity
Plant nitrate content influenced by:
Drought & high T˚C, Lack of sunlight, disease etc.
http://www.agweb.com/article/get-to-know-nitrate-toxicity-naa-wyatt-bechtel/
Warm Season Annuals
iv. Small cereals (Barley,
Rye, Wheat, Oats…)
Use with annual legume (e.g.,
Spring pea) for good silage
Aim for grain development
(late milk-early dough)http://www.progenellc.com/images/imagepage/oats/oats.html
Summary - Grasses
i. Many different species
ii. Good source of nutrients
Mix with legumes
iii. Potential anti-quality factors
E.g., Ergot alkaloids, Prussic acid, etc.
Legumes
i. Alfalfa
ii. Birdsfoot Trefoil
iii. Red Clover
iv. White Clover
v. Sainfoin
vi. Annual legumes e.g., beans, peas
Legumes (cont.)
Fixation of atmospheric N
Positives Negatives
1. High CP 1. Low fiber, high lignin
2. High Ca and Mg 2. Induce bloat
3. High vitamin A 3. Phytoestrogens
4. High yield
3 to 4 cuttings
Alfalfa “Queen of Forages”
http://corlandseeds.ca/Deep%2003.JPG; http://portaldelinterior.com/wp-content/uploads/2013/05/recomendaciones-para-el-cultivo-de-alfalfa-Fuente-Wikipedia.jpg
Alfalfa “Queen of Forages” (cont.)
Highly productive
Idaho = 3.9 tons/acre, 4.3 M tons, $871 M (2014)
Good perennial
5 to 6 year stands
Drought resistant
Very nutritious
Alfalfa “Queen of Forages” (cont.)
Needs well-drained soils
“Heaving”
Winterkill
Low tolerance to overgrazing
Low NSC relative to soluble CP
Bloat problems
Bloat
Accumulation of gasses
“Bloat guard”- Poloxalene
https://quizlet.com/75133666/bovine-gi-rumen-flash-cards/; http://lvspa.org/inc/index.php/more-info/k2-tags/item/74-bloat
Gas
Birdsfoot Trefoil
http://www.extension.umn.edu/garden/diagnose/weed/broadleaf/creeping/birdsfoottrefoil.html;
Birdsfoot Trefoil (cont.)
Tolerant to adverse soil conditions
Acidic, poor drainage, heavy, low native fertility
Exceptional pasture legume
Withstand grazing
Works well with grass e.g., brome & tall fescue
Does not cause bloat (condensed tannins)
E.g., ‘Empire’, ‘Viking’
Legumes
i. Alfalfa
ii. Birdsfoot Trefoil
iii. Red Clover
iv. White Clover
v. Sainfoin
vi. Annual legumes e.g., beans, peas
Red Clover (cont.)
Require well drained soil (pH > 5.5)
Short-lived perennial
Suited for hay or silage
2 or 3 hay crops
Production of phytoestrogens
Phytoestrogens
E.g, Isoflavones (Formononetin)
Plant content varies
Genetics
Use of low-phytoestrogen varieties
Environmental conditions
E.g., fertilizer deficiency
Phytoestrogens (cont.)
Mimic estradiol
“Clover disease”
Low lambing rates, uterine prolapse, dystocia, death
Temporary or permanent infertility (‘defeminization’)
Estradiol Isoflavone, e.g., Formononetin
White Clover (cont.)
Good pasture legume
Highly palatable, nutritious
Commonly planted with grasses
E.g., ‘Ladino’, ‘New York’ (Idaho-adapted)
Mix with Orchardgrass, Tall Fescue
Sainfoin
http://www.wildbeeinternational.com/wbi/wp-content/uploads/2014/03/2013-07-04-14.12.33.jpg
E.g., ‘Shoshone’
Sainfoin (cont.)
Highly palatable
Highly nutritive
Contain phenolics e.g., condensed tannins
Improve protein utilization
Non-bloating nature
Anthelmintic properties (reduce parasites e.g., nematodes)
Can be incorporated into alfalfa pasture
Annual Legumes
E.g., Beans (Faba’s), Peas
Cool-season
Good as silage or for grazing
http://bayoulog.com/2014/10/01/cool-season-wildlife-food-plots/
Summary - Legumes
i. High quality forage
Opportunity to mix with grasses
ii. Reduce the cost of N fertilization
iii. Potential issues
Bloat, Phytoestrogens
Forage Preservation (cont.)
Is forage preservation a perfect process?
Fresh Vegetation Preserved Forage
DM LossesQuality Loss
Haymaking
Objectives
i. Produce a high yielding, high quality crop
ii. Rapid curing
iii. Minimize leaf loss
iv. Minimize cell respiration
v. Avoid leaching losses & molding
vi. Maintain quality in storage
Haymaking
Objectives
i. Produce a high yielding, high quality crop
ii. Rapid curing
iii. Minimize leaf loss
iv. Minimize cell respiration
v. Avoid leaching losses & molding
vi. Maintain quality in storage
Harvesting
http://www.deere.co.za/en_ZA/products/equipment/hay_and_forage_equipment/mower_conditioners/mower_conditioners.page?
When to Harvest?
Impact of plant maturity on DMI & digestibility
Ball et al, 2001. American Farm Bureau Federation Publication 1-01
When to Harvest?
Forage Species Time of Harvest
Alfalfa Bud stage (1st cutting); 1/10 bloom for 2nd and later cuts
Orchardgrass, Tall Fescue Boot to early head (1st cut);every 4-6 weeks after
Red Clover Early to ½ bloom.
Barley, Oats, Rye, Wheat Boot to early head stage.
Sudan-sorghum hybrids Early boot stage.
Weather conditions?
Curing (cont.)
Factors that affect the duration of curing
Initial DM%
Environmental
i. Temperature
ii. Humidity
iii. Wind speed
iv. Solar radiation
Conditioning
How Does Rain Affect Hay Quality
i. Leaching (soluble CHO, CP, minerals)
ii. Increased and prolonged respiration
iii. Leaf shattering
iv. Microbial activity
v. Color bleaching
Risk Assessment
If you were to go ahead, which of the following
has the higher risk?
i. Forage is baled vs. ensiled?
ii. Small vs. large acreage to harvest?
iii. Rain early vs. late in drying period?
iv. Forecasted rain is “full-frontal” vs. “scattered”?
v. Grass vs. Grass-legume mix vs. legume?
vi. Market for damaged hay, drying agents, etc…
Curing (cont.)
Factors that affect the duration of curing
Initial DM%
Environmental
i. Temperature
ii. Humidity
iii. Wind speed
iv. Solar radiation
Conditioning
Conditioning
Treatment of hay crop to accelerate the
drying process.
Mechanical and/or
Chemical conditioning
Mechanical Conditioning
Conditioners bruise, lacerate, crush or crimp
plant to reduce differential drying of leaves vs.
stems
https://www.poettinger.at/img/landtechnik/scheibenmaeher/rc_aufbereiter_th.jpg
Chemical Conditioning
Desiccants/drying
agents
E.g.,
K2CO3,
NaCO3
http://extension.psu.edu/plants/crops/forages/hay-and-silage/harvest-management/chemical-conditioners-for-hay
Reducing Drying Time
http://www.farmingmagazine.com/dairy/forages/haymaking-101-mowing-tedding-and-raking/
Tedding
Baling
https://www.deere.com/en_US/products/equipment/hay_and_forage_equipment/balers/9_series_round_balers/9_series_round_balers.page
Has to be done at the correct moisture
______% moisture?
Consequences of baling when too wet or dry?
DM Losses During Haymaking (cont.)
Process % DM
Respiration 2 - 16
Conditioning (crimper) 1 - 4
Raking at 40-50% moisture 2 - 5
Raking at 10-15% moisture 25 - 30
Baling (rectangular) 2 - 5
Baling (large, round) 15 - 40
Baling When Too Wet
Growth of spoilage microbes (aerobic)
Spoilage bacteria, e.g., bacilli
Yeasts, molds, fungi
Hay (plant sugars, protein) + O2 CO2 + H2O + Heat
Effect of Feeding Moldy Hay in Cattle
Parameter Good Hay Moldy Hay
Hay intake, kg 7.1 6.5
Rumen fermentation characteristics
Total VFA, µ mol/mL 88.0 72.5
Rumen ammonia, mg/dL 23.4 15.5
Digestibility, %
DM 63.7 53.5
CP 76.9 53
Performance
Average daily gain, kg/d 0.73 0.61
Feed:Gain 12.0 13.4Mohanty et al. (25)
Hay Preservatives
Hay preservatives
Reduce losses due to molds & heating
Reduce drying times (can bale at higher T˚C)
Roberts, 2005. https://www.agry.purdue.edu/forageday/2005/article/management%20of%20preservatives-2005_Version3.pdf
Hay Preservatives (cont.)
Preservative Mode of Action
ApplicationMethod
Moisture Content of Hay
Pros & Cons
Weak acid e.g., Propionic acid
Controls mold & bacterialgrowth by altering pH
Liquid-added before baling
Up to 30% Can be stored Corrosive
Buffered acid e.g., Ammonium propionate
Controls mold & bacterial growth
Liquid-added before baling
Up to 30% Not ascorrosive
Not as effective
Bacterialinoculants
Compete with other microbes in hay
Liquid-added before baling
Up to 23% Cannot be stored
Designed for silage prodn
Hay Storage
Recommended % moisture for safe storage
Bale type % Moisture
Small rectangular bales 16 - 18
Round bales (soft center) 14 - 16
Round bales (hard center) 13 - 15
Large rectangular bales 12 - 14
Export hay < 12
Hay Storage
Protect from the elements
http://hallhall.com/blog/haying-with-the-buffalo-on-colorado-ranches/, http://rurification.blogspot.ca/2012_12_01_archive.html
Forage Quality Results
How can laboratory results differ when they
are sent the “same” sample?
https://www.progressiveforage.com/forage-production/harvest-and-storage/decreasing-the-variability-in-hay-tests
Forage Quality Results
Accuracy = how closely the quality measurements
of the submitted sample compares to the true
quality of the lot of forage it represents.
Forage Quality Results (cont.)
Precision = the ability of a laboratory to
repeatedly produce the same results.
Accuracy of forage analysis is limited by the
weakest link in the analytical procedure
Sample Collection
https://picclick.com/Hay-Probe-Bale-Sampler-Drill-Type-24-Depth-171080086455.html; https://www.ag.ndsu.edu/carringtonrec/center-points/managing-hay-resources-when-the-sun-won2019t-shine
Hay Sampling Protocols
Reducing sampling error
a. Identify a single hay lot
b. Sample close to the point of sale/feeding
c. Choose a sharp, well-designed probe (3/8 to 3/4
inch)
d. Sample at random (systematically)
Hay Sampling Protocols (cont.)
Reducing sampling error (cont.)
e. Use the proper technique
https://www.progressiveforage.com/forage-production/harvest-and-storage/decreasing-the-variability-in-hay-tests
Hay Sampling Protocols (cont.)
Reducing sampling error (cont.)
f. Take the right amount (1/2 lb or 250 g)
g. Handle the sample properly
h. Never split the sample before grinding it first
i. Choose a qualified lab
Is it certified e.g., National Forage Testing Association
(NFTA)?, Quality control steps?, Procedures, e.g., AOAC?
Quality Guidelines for Alfalfa Hay
http://hayandforage.com/article-1211-USDA-Weekly-Hay-Market-Prices---February-28-2017.html
Quality Guidelines for Grass Hay
http://hayandforage.com/article-521-USDA-Hay-Market-Prices-–-February-16-2016.html
Relative Feed Value (RFV)
Widely used index to market hay
RFV = % Digestible DM × DM intake (% of BW)
1.29
% Digestible DM % = 88.9 – (ADF% × 0.779)
DM intake (% of BW) = 120 ÷ NDF%
Total Digestible Nutrients (TDN)
Index that estimates energy supply
Earlier equations based on ADF;
TDNLegumes and grasses = 88.9 – (0.79 × ADF%)
NRC, 2001
TDN = dNFC + dCP + (dFA × 2.25) + dNDF – 7
Relative Feed Quality (RFQ)
Another forage quality measure
RFQ = TDN × DM intake (% of BW)
1.23
RFV = % Digestible DM × DM intake (% of BW)
1.29
Forage Production
What is the goal of most forage production
systems?
Strategies to achieve that goal?
i. ?
ii. ?
iii. ?
iv. ?
Forage Production (cont.)
In some instances, forage quality cannot be
optimized!
If we cannot grow forages or if forages are too
expensive, what could we use to feed cattle?
Use of Crop Residues as Feed
1 kg of grain
≈ 1 kg of residue
≈ 400 M tonnes of residue/yearhttp://www.startribune.com/ethanol-industry-gets-its-own-corn/290370141/; https://www.pinterest.com/pin/132785888986916857/
Use of Crop Residues as Feed (cont.)
Examples of crop
residues
?
?
?
http://maxpixel.freegreatpicture.com/Straw-Bale-Harvested-Wheat-Field-Summer-853333
Use of Crop Residues as Feed (cont.)
What are the advantages?
i. ?
ii. ?
iii. ?
What is the biggest drawback?
Improving the Nutritive Value of Crop Residues for Livestock
Some form of processing required to;
i. Increase acceptability of high fiber
ii. Increase DMI
iii. Enhance rate and extent of digestion
iv. Increase production performance and economic
returns
Improving the Nutritive Value of Crop Residues for Livestock (cont.)
Types of processing methods;
i. Physical-mechanical
ii. Chemical
iii. Microbiological
Improving the Nutritive Value of Crop Residues for Livestock (cont.)
Problem with processing of residues;
i. Cost of treatment often > value of end product
ii. Treated product may be of low to moderate
value
Might still need to supplement protein &/or
energy!
Physical Treatments: Grinding & Pelleting
Grinding
i. Decreases particle size
ii. Increases surface area
iii. Increases the bulk density
of forages https://buildasoil.com/products/alfalfa-meal
Physical Treatments: Grinding & Pelleting (cont.)
Pelleting
i. Further increases the
bulk density
i. Reduces dustiness
ii. Increases ease of handling http://www.ghatnutrition.com/alfalfa-pellets-17/
Physical Treatments: Grinding & Pelleting (cont.)
Benefits of grinding and pelleting long hay
-60
-40
-20
0
20
40
60
80
100
DMI Daily gain Feed:Gain
% Improvement
Beardsley, 1964. JAS. 23:239-245
Physical Treatments: Grinding & Pelleting (cont.)
Improvements in DMI & ADG inversely
related to unprocessed forage quality!
Grinding & pelleting in combination with protein
supplementation
Chopping = inconsistent improvements
Physical Treatments: Grinding & Pelleting (cont.)
Grinding and pelleting generally depresses
digestibility!
Up to 15% for grasses & 6% for legumes
Greater depression with higher DMI
However, high DMI = high GE intake = high DE intake!
Physical Treatments: Grinding & Pelleting (cont.)
Decrease in digestibility due to reduced fiber
digestion;
Higher DMI = shorter rumen residence time
Decrease in particle size = less time spend time
eating and ruminating
Impact?
Physical Treatments: Grinding & Pelleting (cont.)
Grinding and pelleting often reduces ruminal
digestion of forage protein!
Heat produced during grinding & pelleting
i. Decreases ruminal degradation (increases by-
pass protein)
ii. May cause Maillard reactions
Physical Treatments: Steam Explosion
Primarily used for pre-treatment of
lignocellulosic material for ethanol & biogas
production.
Superheating for a short time
i. Hydrolyzes hemicellulose to sugars
ii. Breaks down lignin bonds with carbohydrates
Physical Treatments: Steam Explosion (cont.)
Some of the reported benefits;
i. Increase in DMI
ii. Increase in DM, NDF, cellulose digestibility
iii. Increase in ADG
iv. Improvement in feed efficiency
Challenge = cost!
Physical Treatments: Mechanical Separation of Plant Parts (cont.)
Leaf fraction Stem fraction
Surface area, mm2/g 13.6 6.6
Ash, g/kg 102 79
Nitrogen, g/kg 15.2 11.2
NDF, g/kg 673 699
ADF, g/kg 384 407
Lignin, g/kg 33.1 51.8
Intake, g/kg of BW0.75 44.2 34.4
NDF digestibility, % 58.9 48.0
ADF digestibility, % 57.6 49.0Laredo and Minson, 1975. Br.J.Nutr. 33:159-170
Physical Treatments: Mechanical Separation of Plant Parts
Improvements must be significant to offset
processing costs e.g.,;
i. Transportation of forages to a central processing
location
ii. Drying of fresh forages prior to separation
(energy intensive)
Chemical Treatments
Involves the use of either;
i. Hydrolytic agents
e.g., NaOH, KOH, Ca(OH)2, NH3, urea
ii. Oxidative agents
e.g., SO2, ozone
iii. Combination of hydrolytic agents and oxidants
Chemical Treatments: Hydrolytic Agents
Hydrolytic treatments
Partially solubilizes hemicellulose, lignin,..
Disruption of H-bonds in cellulose
http://www.intechopen.com/books/cellulose-fundamental-aspects/structural-characteristics-and-thermal-properties-of-native-cellulose
Chemical Treatments: Oxidative Agents
Oxidative treatments
Degrade a proportion of cell wall lignin
http://http://www.intechopen.com/books/ionic-liquids-new-aspects-for-the-future/applications-of-ionic-liquids-in-lignin-chemistry
Chemical Treatments: Hydrolytic Agents
Hydrolytic agents = Alkali’s e.g., NaOH,
Ca(OH)2, NH3, urea
Disrupt lignocellulosic structure
i. Partially solubilize bonds between lignin, and
cellulose and hemicellulose
ii. Disrupt H-bonds in cellulose
http://www.intechopen.com/books/cellulose-fundamental-aspects/structural-characteristics-and-thermal-properties-of-native-cellulose
Chemical Treatments: NaOH
Used at 3 to 5% of DM
Wet application = soak cereal straw in NaOH
for 3 days and wash off residual chemical
Leaching of nutrients during washing (10-15% DM
loss)
Disposal of residual NaOH
Chemical Treatments: NaOH
73.7
35.9
5.6
67.4
32.6
4.88
0
10
20
30
40
50
60
70
80
NDF ADF Lignin
Effect of NaOH Treatment on Fiber Content (%) of Bermuda grass
Control NAOH trt.
Utley et al., 1982. Can. J. Anim. Sci. 62:499-505
Chemical Treatments: NaOH
48.8 49.4
43
55.8 55.4
46.8
0
10
20
30
40
50
60
Dry matter NDF ADF
Effect of NaOH Treatment on Nutrient Digestibility (%)
Control NAOH trt.
Utley et al., 1982. Can. J. Anim. Sci. 62:499-505
Chemical Treatments: NaOH
0.65
11.2
0.69
9.91
0
2
4
6
8
10
12
ADG, kg/d Feed:Gain
Effect of NaOH Treatment on Production Performance
Control NAOH trt.
Utley et al., 1982. Can. J. Anim. Sci. 62:499-505
Chemical Treatments: NaOH
Treatment issues
i. Hazardous (caustic alkali)
ii. Na accumulation in manure
iii. Expensive
iv. Wet application = leaching + disposal of residual
NaOH
Chemical Treatments: Ca(OH)2
Quicklime, burnt lime (CaO) used
Add water and forms hydrated lime (Ca(OH)2)
CaO + H2O Ca(OH)2 + Heat
Handle with care when mixing!
“Quicklime dust” causes severe irritation!
Chemical Treatments: Ca(OH)2
36.3 36.4 36.7
51.8 50.353.1
0
10
20
30
40
50
60
Dry matter Organic matter NDF
Effect of CaO treatment on Nutrient Digestibility (%) of Corn Stover
Untreated Treated
Shi et al., 2015. J Anim Physiol a Anim Nutr. DOI: 10.1111/jpn.12381
Chemical Treatments: Ammoniation
Most widely used method of alkali treatment
in the US
Not as effective as NaOH treatment
But increase CP content
Works better with poor quality forages/residues
< 5% CP
< 45 – 50% TDN
Chemical Treatments: Ammoniation(cont.)
Application rate = 1.5 to 3% of DM (~60
lb/ton of dry forage)
Chemical Treatments: Ammoniation(cont.)
Key reaction: Anhydrous NH3 (liquid) to gas
(several weeks)
Gas can penetrates forage (but losses)
Better reaction with;
i. High moisture in forage
ii. High ambient temperature
Chemical Treatments: Ammoniation(cont.)
82.1
2.56
31.5
73.9
11.875
51.2
0
10
20
30
40
50
60
70
80
90
NDF content CP content NDF digestibility
Effect of Ammoniation on Nutrient Composition & Digestibility (%) of Wheat Straw
Untreated Treated
Bals et al., 2010. Anim. Feed Sci. Technol. 155:147-155
Chemical Treatments: Ammoniation(cont.)
Increases intake and digestibility
Can partially replace “conventional” hay with
treated straw
Up to 65% in late-gestation cows
Up to 35% in cows nursing calves
Chemical Treatments: Ammoniation(cont.)
Always consider ammoniation cost vs. hay price!
Estimated cost to treat 1 ton of forage:
$26-30 for anhydrous ammonia
$5-9 for plastic
Total = $31-39/ton
If wheat straw = $45-50/ton, ammoniated straw =
$76-89/ton
Chemical Treatments: Urea
Urea used as a source of NH3
Urea NH3 + CO2
Mixed with roughage in silo, pelleter, etc.
Safer than handling anhydrous NH3
Variable results
Moisture content? Urease activity? Temperature?
Urease
Chemical Treatments: Alkaline Hydrogen Peroxide (AHP)
10.4
45.1
25.9
11.5
56.2
2.3
0
10
20
30
40
50
60
Lignin Cellulose Hemicellulose
Effect of AHP Treatment on Nutrient Composition (%) of Wheat Straw
Untreated AHP Treated
Chaudhry, 1998. Anim. Feed Sci. Technol. 74:315-328.
Chemical Treatments: Alkaline Hydrogen Peroxide (AHP)
49.446.4
58.8
76.1
67
85.4
0
10
20
30
40
50
60
70
80
90
NDF ADF Cellulose
Effect of AHP Treatment on Nutrient Composition (%) of Wheat Straw
Untreated AHP Treated
Chaudhry, 1998. Anim. Feed Sci. Technol. 74:315-328.
Chemical Treatments: Peroxides
Effective in improving digestibility
Higher cost than NaOH or NH3 treatment
Not as practical as NaOH of NH3 treatment
Some peroxides are pollutants (e.g., ozone)
Microbial/Enzymatic Treatments
Advantages;
i. Fewer chemicals
ii. Lower energy inputs
Disadvantages;
i. Longer treatment time
ii. Loss of substrate during incubation
Microbial Treatments: White-rot Fungi
Effective in degrading lignocellulosic material
But loss of carbohydrates (CHO);
i. 1st utilize soluble CHO
before producing
lignin-degrading enzymes
ii. Degrade CHO from
delignified cell wallhttp://www.mykoweb.com/articles/DeconstructingDecomposing.html
Enzymatic Treatments
Use of various fiber degrading enzymes;
i. Cellulases,
ii. Xylanases
iii. Ligninases, etc.
Inconsistent results!!
High cost