Mycotoxins - Penn State University

Mycotoxins:
Managing a Unique
Obstacle to Successful
Dairy Production
Lon W. Whitlow
North Carolina State University
Raleigh
Mycotoxin:
Poison
Produced By
Molds
(Filamentous Fungi)
The Mycotoxin
Blue Book
Nottingham University
Press
Edited by
Dr. Duarte Diaz
Mycotoxins are a diverse group of fungal metabolites
(chemicals produced by a mold) that cause an
undesirable effect in exposed animals.
SUMMARY
Contact:
CAST
Council for Agricultural
Science and Technology
4420 W. Lincoln Way
Ames, Iowa 50014
Telephone
515-292-2125
Report # 139
1. Mycotoxins are prevalent in feeds
2. Mycotoxins are toxic to dairy cattle
3. High levels cause acute effects in cattle, including death
4. Low levels cause the greatest economic loss - chronic
losses in milk production & more disease
5. Mycotoxins can be the root cause
of health and production problems.
6. Prevention is important
7. Treatments are effective
Primary Toxigenic Molds and Mycotoxins
* Those Thought Most Prevalent and Toxic to Dairy Cattle
Fusarium
*Deoxynivalenol
*Zearalenone
*T-2 Toxin
*Fumonisin
Moniliformin
Nivalenol
Diacetoxyscirpenol
Butenolide
Neosolaniol
Fusaric Acid
Fusarochromanone
Wortmannin
Aspergillus
*Aflatoxin
Ochratoxin
Sterigmatocystin
Fumitremorgens
Fumigaclavines
Fumitoxins
Cyclopiazonoic Acid
Gliotoxin
Alternaria Claviceps
Stachybotrys AAL toxin Ergots
Stachybotryotoxin Lupinosis Fescue Alkaloids
Penicillium
Ochratoxin
*PR Toxin
Patulin
Roquefortine C
Mycophenolic Acid
Penicillic Acid
Citrinin
Penetrem
Cyclopiazonic Acid
1

Primary Toxigenic Molds and Mycotoxins
* Those Thought Most Prevalent and Toxic to Dairy Cattle
Fusarium
*Deoxynivalenol
*Zearalenone
*T-2 Toxin
*Fumonisin
Moniliformin
Nivalenol
Diacetoxyscirpenol
Butenolide
Aspergillus
*Aflatoxin
Ochratoxin
Sterigmatocystin
Fumitremorgens
Fumigaclavines
Fumitoxins
Cyclopiazonoic Acid
Gliotoxin
Penicillium
Ochratoxin
PR Toxin
Patulin
Penicillic Acid
Citrinin
Penetrem
Cyclopiazonic acid
Known Postulated
Mold Species 1,100 1,500,000
Secondary Metabolites 3,200 3,000,000
Neosolaniol Mycotoxins
Fusaric Acid
Fusarochromanone
Wortmannin
> 300 30,000
Alternaria Claviceps
Stachybotrys AAL toxin Ergots
Stachybotryotoxin Lupinosis Fescue Alkaloids
Do mycotoxins also assist fungi
to infect animals?
Fungal infections in animals are termed mycoses.
Fungal pneumonia, abortions, mastitis and intestinal infections
Animals resist mycoses unless immune suppressed.
Mycotoxins produced by fungi cause immune suppression,
and thus may assist fungi in infecting animals.
Hemorrhagic bowel syndrome
Caused by A. fumigatus
Forsberg
Do mycotoxins also assist fungi
to infect animals?
Fungal infections in animals are termed mycoses.
Fungal pneumonia, abortions, mastitis and intestinal infections
Animals resist mycoses unless immune suppressed.
Mycotoxins produced by fungi cause immune suppression,
and thus may assist fungi in infecting animals.
In studies of A. fumigatus
infections in ruminants,
gliotoxin and/or T-2 toxin, which are
both potent immune suppressing
mycotoxins, were always present,
when analysed.
A mycotoxin binder may prevent HBS
Hemorrhagic bowel syndrome
Caused by A. fumigatus
Forsberg
Why do fungi produce mycotoxins?
As a secondary metabolite, mycotoxins have no direct
function in fungal metabolism.
John Deere Co.
Main theories for their production are:
1. Protection of the fungus
2. Assist the fungus in creating an
environment for survival and growth.
Do mycotoxins also assist fungi
to infect animals?
Fungal infections in animals are termed mycoses.
Fungal pneumonia, abortions, mastitis and intestinal infections
Animals resist mycoses unless immune suppressed.
Mycotoxins produced by fungi cause immune suppression,
and thus may assist fungi in infecting animals.
In studies of A. fumigatus
infections in ruminants,
gliotoxin and/or T-2 toxin, which are
both potent immune suppressing
mycotoxins, were always present,
when analysed.
Hemorrhagic bowel syndrome
Caused by A. fumigatus
Forsberg
Mycotoxin Occurrence and Concentrations in Feeds
From North Carolina Producers Over 13 Years
Aflatoxin Deoxynivalenol Fumonisin T-2 Toxin Zearalenone
Number 3266 5053 822 5136 4563
Total
Positive, % 10 46 42 8 15
Low, % 6 18 33 2 7
(300 ppb)
2

Mycotoxin Contamination of 1988 Corn
Collected from July to December from 82
Feed Manufacturers in 7 Midwestern States
Russel et al., 1991
State N Aflatoxin, % T-2, %
Iowa 40 5 18
Nebraska 22 0 18
Minnesota 27 0 15
Illinois 46 13 7
Indiana 5 0 7
Ohio 27 7 11
Michigan 9 0 33
TOTAL 186 5% 13%
Mold Count Interpretations*
Safe Levels < 10,000 CFU/g
Questionable Levels 10,000 - 100,000 CFU/g
Caution Levels 100,000 - 1,000,000 CFU/g
Problem Levels > 1,000,000 CFU/g
Significance of mold counts are highly subjective,
depending on mold identification, mycotoxin formation
and feed deterioration.
Unique Concerns about Ruminant
Mycotoxicoses
Consumption of a variety of feedstuffs, including grains, byproduct
feeds, pasture, hay and silage, results in potential
exposure of ruminants to a broad array of mycotoxins and
multiple mycotoxin exposure.
This array of mycotoxins includes some not normally found in
grains and not routinely analyzed, and results in toxicities not
seen in monogastric animals.
Mycotoxin degradation and transformation in the rumen may
reduce the incidence of acute toxicity, but may increase the
problem of chronic, sub-clinical toxicity.
Rumen transformation of mycotoxins may alter expected
symptoms.
60%
50%
40%
Percent of Total 30%
Dairyland Laboratories 2002 Mold Counts
20%
10%
0%
2001 - 1987 samples 2002 - 2303 samples
10-10,000 44% 50%
10,000-100,000 15% 14%
100,000-10,000,000 37% 33%
>10,000,000 4% 3%
Mycotoxins &
Molds Occur in
Most Feeds
Including Grain,
Hay and Silage
John Deere Co.
Primary Mechanisms Through Which
Mycotoxins Affect Animals
• Reduction of feed intake
• Reduced nutrition of the animal
– reduced nutrient content of the feed,
– reduced nutrient absorption and
– alter/block nutrient metabolism
• Suppression of immunity
• Hormonal effects - primarily estrogenic
• Antibiotic effects on rumen fermentation
• Cellular death - various target tissues
• Increased stress - interactions with other stress
3

Mechanisms
Mycotoxins and Immunity
Aflatoxin T-2 Toxin
Inhibition of Protein Synthesis +++ +++
Thymus Atrophy
Necrosis of Gut-
+++ +++
associated Lymph Tissue +++
Cell Mediated Immunity +++ +++
Humoral effects,
Antibody production + +++
+ to +++ lesser to greater effect Pier, 1994
Mycotoxin Concerns Have Increased
• Learned more about mycotoxins & their toxicity
• Better analytical methods – cheaper & faster
• High producing cows are more susceptible
– More stress - more disease
– Nutrient deficiencies
• Low ruminal mycotoxin degradation - increases toxicity
– Higher feed (and grain) consumption increases rumen turnover
– Lower fiber diets - low rumen pH - fewer protozoa
ERGOTS
Claviceps
Fescue Fungus
Lameness
Necrosis of extremities
Reduced performance
Agalactia
Reduced fertility
Lameness
Necrosis of extremities
Fescue foot
Fat necrosis
Agalactia
Summer toxicosis
FGIS
Tolerance
< 0.3% sclerotia
NCSU
Univ Nebraska
Univ. Georgia
Normal Immune System Function
Around Parturition in the Dairy Cow as Indicated by
Neutrophil and Lymphocyte Function
Immune Function
(% of Controls)
140
120
100
80
60
40
20
0
Calving
-6 -4 -2 0 2 4 6
Week Around Parturition
Pasture Associated Mycotoxins
Neutrophil
Function
Lymphocyte
Function
Kehrli et al., 1989.
Fescue fungus Ergot alkaloids
Ryegrass staggers lolitrems-tremorgens
Paspalum (Dalisgrass) staggers paspalitrems (ergots)
Diplodiosis D. maydis toxin
(Grazed corn fields)
Photosensitization
(Facial Eczema-NZ) sporidesmin
(Geeldikkop-Africa) ?
(Lupinosis - Europe) phomopsin
Slobber Syndrome slaframine (red clover)
Locoism swainsonine
------------------------------------------------------------------
Common mycotoxins such as aflatoxin, DON, ZEN, T-2,
and others.
Fumonisin is produced by
Fusarium verticillioides, formerly moniliforme
4

Penn State
Penn State
Fumonisin Induced Equine Leucoencephalomalacia
Penn State University
Daily Milk Production of Dairy Cows (Holsteins and
Jerseys) Consuming Diets With or Without Corn
Naturally Contaminated With Fumonisin
Diets Contained

Effect of Corn Infected by Gibberella Zeae on Dairy Cattle
Diets
Infected corn in diet, % 0% 20% 40%
Diet Zen (ppb) 0 100 200
Diet DON (ppb)* 0 2400 4800
D.M. Intake (% BW) 2.90 2.85 2.79 n.s.
Milk, (kg/day) 22.7 22.9 23.2 n.s.
4% FCM, (kg/day) 22.1 22.2 22.6 n.s.
Bodyweight Gain, (kg/d) 0.87a 0.60b 0.49b N.S. = not significant, a & b, p < .05
Actual corn not analyzed, but corn form the same field which reduced intake in swine contained
DON. 3x3 Latin Square. 18 cows total. Periods of 21 days.
Noller, et al., 1979. J. Dairy Sci. 62:1003
Effect of DON on First Lactation Dairy
Cows in Mid-lactation (6 cows/group)
Diet Mean Difference
A B C B+C A-(B+C) P>
DON, ppb 36 2686 6393 4539
DMI, lb 35.9 35.0 35.9 35.5 0.4 n.s.
Milk, lb 50.2 47.1 47.4 47.2 3.0 .16
Fat Test, % 3.9 2.8 3.3 3.0 0.9 .05
4% FCM, lb 47.6 39.9 42.7 41.3 6.3 ND
Statistics: Only linear and quadratic effects were tested. There was a sign. Quadratic effect for fat.
Means for diet A vs B or A vs C were not tested.
Means for diet A vs B+C were tested only for milk, which was not sign. at p> .16
The effect on fat and FCM were much greater than on milk alone.
Charmley, et al. 1993. J. Dairy Sci. 76:3580.
Toxicity of Deoxynivalenol in Dairy Cattle
5 ppm DON Reduces FCM 2.6 kg or 5.7 lb
49
48
47
4% FCM
46
lb/d
45
44
43
42
41
40
DON Control 2.5 ppm 5.0 ppm 5.0 ppm
MTB-100 0 0 0 10 g/cow/d
Acosta, Mieres, and La Manna, Uruguay, Unpublished
Rolling Herd average Milk, Lb.
Relationship of Deoxynivalenol
to Change in Rolling Herd Average Milk
300 HERDS 50,000 COWS
Deoxynivalenol level in Concentrate, ppb
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
-1800
100
300
500
700
900
Rolling Herd
Ave. Milk
Whitlow et al. 1991. North Carolina State University, 1982-1983
Effect of DON on Ruminal Protein Synthesis
Danike et al., 2005 J Animal Physiol.
and Animal Nutrition 89:303-315.
Duodenal
Flow of:
Crude Protein,
g/day
RUP, g/day
Microbial
Protein, g/day
Metabolizable
Protein, g/day*
Control
1180
225
862
1091
* 20% less MP
DON
3.1 ppm
950
186
680
871
Rumen ammonia levels post-feeding a
control diet or DON contaminated diet
A second study confirmed the reduced
flow of metabolizable protein.
Danike et al., 2006 J Animal Physiol.
and Animal Nutrition 90:103-115.
Milk Production (lb/d) for Dairy Cows
(Holsteins and Jerseys) Consuming Diets Naturally
Contaminated With 2500 ppb DON and 270 ppb ZEN,
With and Without a Clay Sorbant (0.5 lb/cow daily)
Average Daily Milk (lb)
56
55
54
53
52
51
50
49
All Cows
55.04
Added
51.85 Adsorbent
No
Adsorbent
N = 83 N = 82
P < 0.05
3.2 lb Milk
Control
Sorbant
North Carolina State University
6

Fusarium graminearum or roseum and also labeled Gibberillium
Zearalenone Affected Open Heifers
Showing Mammary Enlargement
A Field Report of Zearalenone Toxicosis
Ration Contents: Zearalenone 660 ppb
Deoxynivalenol 440 ppb
Aflatoxin 88 ppb
Herd Effects Diarrhea in 1/3 of cows
Irregular estrus cycles
Pregnant cows in estrus
Failure to conceive
Vaginitis
Low erratic milk production
Mammary gland enlargement in heifers
Coppock et al., 1990. Vet.
Human Toxicol. 32:246
Zearalenone
Estrogenic effects
Competes with estrogen for binding sites
Reduces reproductive performance
Pigs most susceptible
- swollen reproductive organs
Sheep - rectal prolapse
Zearalenone Affected Open Heifers
Showing Mammary Enlargement
Conception rate for dairy heifers administered
pure zearalenone at 250 mg 1 daily for one estrous
cycle prior to insemination plus 45 days afterward.
Control 87
Zearalenone 62
Conception Rate, %
n = 36 P < .065
Based on expected DM intake, Zen was approx. 25,000 ppb.
Weaver et al., 1986. Am J. Vet Res. 47:1395.
7

Zearalenone: Reproductive Effects in Dairy
Heifers Fed Zearalenone Contaminated
Hay (~ 500 ppb) or Clean Control Hay
Services/Pregnancy Mean
Location Pregnancy
Unit 1 Unit 2 Mean Rate %
Clean Hay 1.23 1.54 1.38 72
ZEN Hay 1.90 2.00 1.95 51
n = 40
North Carolina State University, Unpublished
Theoretical Response of Heifer
Conception Rate to Dietary Zearalenone
Conception
Rate, %
80
70
60
50
40
30
20
0
2
6
10
14
18
22
26
30
34
Dietary Zearalenone, ppm
T-2 Toxin Symptoms
Digestive disorders
-Lower intake and production
-Acidosis
-Ulcers
-Intestinal hemorrhage
-Diarrhea (Bloody)
Poor fresh cow transition
Increased disease (Metabolic & Infections)
Reduced fertility
Relationship of herd fertility with dietary “zearalenone” and
urinary “zearalenone” in pastured dairy cows in New Zealand
Dietary Blood
Farms ZEN (est.) “ZEN”
n ppb ppb
Low Fertility 8 400 1.14
High Fertility 6 220 0.27
Low fertility = 10-30% of cows failing to conceive after multiple services
Symptoms included mammary enlargement and swollen and redden vulvas
“Zen” = Zearalenone and derivatives reactive to custom ELISA
Sporsen and Towers 1995. Ruakura Research Center, New Zealand
Fusarium sporotrichoides University of California, Davis
Effect of 350 ppb Dietary T-2 Toxin on Daily Milk
Production at the Randleigh Jersey Research Farm
Daily Milk, Lb.
46
44
42
40
38
36
34
32
30
1
5
10
14
18
22
26
30
34
38
42
46
50
54
58
Whitlow, NCSU, 1986
Binder Added
Days
Binder Removed
Binder Added
8

Hemorrhagic bowel syndrome associated with T-2 toxin
Example of aflatoxin effects on the liver of the
guinea pig, from high to low levels of aflatoxin
Richard, USDA, ARS, National Disease Center, Ames, Iowa and CAST, 1989.
Mycotoxin Excretion Via Milk
Excretion, % of diet conc.
Aflatoxin 1.7 Range 1 – 2
Deoxynivalenol < 0.02
Zearalenone < 0.70
T-2 toxin < 0.20
Fumonisin < 0.01
Ochratoxin < 0.03
Aspergillus flavus produces aflatoxin
Estimated Milk Production Loss in Dairy Cattle
Following a One Month Exposure to Aflatoxin.
Milk Loss, lb.
30
25
20
15
10
5
0
14
12
10
8
6
4
2
0
0 200 400 600 800 1000
Legal limit
Of 20 ppb
Dietary aflatoxin, ppb
Relationship Between Aflatoxin B 1 Intake (mg/day) and
Milk Concentration of Aflatoxin M 1 (µg/L), Van Egmond, 1989
Milk aflatoxin concentration = 1.7% diet conc.
Milk
Aflatoxin
M 1
(µg/L)
.
. . . .
. . .
. .
...
.
. .. .
.
.
.
.
AFM1
0 5 10 15 20 25 30 35 40
.
. .
.
Aflatoxin B 1 Intake (mg/day)
.
.
.
.
Van Egmond, 1989
9

Percent of
Total
Dairyland Laboratories 2002
Mold Identification
35%
30%
25%
20%
15%
10%
5%
0%
Penicillium Aspergillus Mucor Rhizopus Fusarium
2001-581 30% 6% 18% 8% 18% 17% 3%
2002-665 35% 10% 20% 8%
Specific Molds
12% 11% 3%
Cladospori
um
Other
N=1950
N=2200
Managing A Mycotoxin Problem
• Diagnosis
– Observe for general symptoms
– Process of elimination (Rule out other possible causes such as
nutrition, disease, and management)
– Add a mycotoxin binder (sorbant) to the diet
– Test feeds for common mycotoxins
(DON, T-2, ZEN, FB, AF)
• Prevention
– Manage feed to reduce spoilage
– Use mold inhibitors
– Use transition rations – reduce stress
Potential Methods for Treatment &
Prevention of Aflatoxin Toxicity
CHEMICAL
BIOLOGICAL
PHYSICAL
•Ammoniation
•Microbial
•Grain Cleaning/Seperation
Commonly used on
cottonseed and corn
Irreversible if done
properly
Enzymatic
degradation of specific
mycotoxins
Potential treatment
Effective
Reduces fines where
concentration of aflatoxin is
high
Can be used in the
feed mill or on the
•Non-Toxic strains •Heating - peanuts
farm
May compete with or 40-80% reduction
•Sodium Bisulfite
exclude toxic strains of
•Irradiation
aflatoxin
Decreased
Exposure to UV light
palatability
Practical?
•Adsorbents
Clays, carbons, glucans,
(Eaton and Groopman, 1994)
inorganic polymers
Selected Penicillium Mycotoxins
• PR Toxin - Related to reduced intake, rumen stasis,
intestinal irritation, abortion and retained placenta in
dairy cattle. A marker for problem silages (Seglar)
• Roquefortine C - Implicated in toxic silage
• Mycophenolic Acid - Implicated in toxic silage
• Ochratoxin - Kidney Toxin, toxic to calves but, not
toxic to functional ruminants -adults
• Patulin - A common mycotoxin in silage. Effects
ruminal fermentation. Has been implicated in deaths of
cows (Lacey), but has received little study.
Managing A Mycotoxin Problem
• Treatment
– Encourage feed intake
– Remove or dilute contaminated feeds
– Feed “CLEAN” feed to
transition cows
– Evaluate nutrients:
Antioxidants: Vitamin E, Cu, Zn, Mn, Se
Vitamin A and/or carotene
Protein, Fat, Adequate Effective Fiber
– Feed additives: buffers, microbials
– Mycotoxin binders are shown to be effective
Milk
Aflatoxin,
ppb
Clearance and Appearance of Aflatoxin in Milk
Associated With Consumption of Aflatoxin
Contaminated Corn in Diets
With or Without the Addition of Clay Products
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Days
Aflatoxin Aflatoxin Aflatoxin
removed added
removed
NO CLAY
CLAY
ADDED
(mean of 3
clays)
10

Effect of Feed Additives on % Reduction
in Milk Aflatoxin Residues
%
80
70
60
50
40
30
20
10
0
54.1
67.3
61.2
64.6
Bentonites
added at 1.2%
31.4
58.5
Mycrosorb
5.4
Mycosorb 0.05% Activated Carbon 0.25%
Efficacy of Various Adsorbents Added to Diets at
0.5% to Reduce Milk Aflatoxin Concentrations When
Diets Contain 170 ppb Aflatoxin B1
120
100
100
Milk
80
Aflatoxin
60
% of
40
Control
20
0
104 92 93
MTB-100
Control
Stroud, J.S., et al. 2006. J Dairy Sci. (abstr.)
87 ** * *
58 65 52 55
Milbond-TX
Astra Ben 20
Condition Ade
Toxinil+
Novasil+
Mexsil
Ultrasorb
* Significant P < .05
The problem of sampling a non-uniform lot of feed
Protein Aflatoxin
12 12 11 13
12 13 12 13
12 13 11 12
12 11 12 13
13 12 11 12
Average = 12
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 8000 0 0
0 0 0 0 0
Average = 400
46*
33* 39* Efficacy of Adsorbents Added Diets at at Different Inclusion Rates
(Clay at 1.2%, Glucan at 0.05% and Carbon at 0.25%) to Reduce
Milk Aflatoxin Concentrations in Diets Containing 55 ppb Aflatoxin
Study A
95
Study B
69*
35*
41*
* P < 0.05
Milk Aflatoxin
% of Control
100
90
80
70
60
50
40
30
20
10
0
MS FG AB-
20
AB-
20
Adsorbent Product
Diaz et al., 2004,
Mycopathologia 156:223-226 & 157:233-241
RC MTB- AC-A
100
Type Amount In Vitro
Product % Binding, %
MS - Mycrosorb - Clay - 1.2% 98.4
FG - Flowguard - Clay - 1.2% 95.1
AB-20 - Clay - 1.2% 98.0
RC - Red Crown- Clay - 1.2% 98.5
MTB-100 - - Glucan - 0.05% 96.6
AC-A - - Carbon - 0.25% 99.9
Sampling &Testing Feeds for Mycotoxins
Mold spore count - Reflects deterioration but not mycotoxins
Mold I.D. - Suggests potential mycotoxins
Mycotoxins - AF, DON, ZEN, FB and T-2.
Sampling - Imprecise and difficult.
Occurs in unevenly distributed spots
Blend feed prior to sampling
Take numerous subsamples and composite
Labs -Identify accurate, fast, and cost effective lab
Mailing -Freeze wet samples, dry samples in paper bags
-Use overnight delivery
Effect of Sample Size on Estimated 95% Confidence Interval
of Test Results for Cottonseed Containing 100 ppb Aflatoxin
95% Confidence Interval
Sample Size Sub-samples Low High
lb. No. ppb ppb
2 4 0 271
4 9 0 222
9 20 13 187
18 41 37 163
35 78 53 147
70 159 64 136
Whitaker, Dickens,Giesbrecht. 1991. In: Mycotoxins and Animal Foods. CRC Press.
11

What concentrations of
mycotoxins are safe?
No amount of mycotoxin can be considered safe
Errors in sampling and analysis may be misleading
Only a few mycotoxins are analyzed
Presence of one mycotoxin suggests presence of others
and many mycotoxins exist
Mycotoxins interact with other mycotoxins and other
factors such as nutrition and stress producing
variable results
Mold Mushrooms Moisture
Silos need to be sized to the herd for rapid feed out
SUMMARY
1. Mycotoxins are prevalent in feeds
2. Mycotoxins are toxic to dairy cattle
3. High levels cause acute effects in cattle - death
4. Low levels cause the greatest economic loss - chronic
effects – milk loss – greater disease
5. Mycotoxins can be the root cause of various problems.
6. Prevention is important
7. Treatments are effective
8. Adsorbents are the best treatment
Conditions in Silage Leading to Deterioration,
Mold Growth and Mycotoxin Formation
Aeration
Yeast Growth
Listeria
Starch and Sugars
Consumption of
Lactic Acid
Other Aerobic
Microorganisms
Deterioration
Ethanol
Increased pH
Penicillium Other Molds
Mold Growth
Silage Management – Summary
Choose appropriate hybrids
Harvest At Proper Stage of Maturity
and Moisture
Consider Processing
Fill the Silo Fast (Not too fast)
Pack for Good Density
Cover Well
Use Effective Fermentation Aid
Manage the Feeding Face
Discard the Spoilage
Mycotoxin Formation
Final Question:
How much poison is acceptable in a dairy ration?
Thanks
12