HARVESTED FORAGES
Green Chop and Hay
pp. 263-267
WHY HARVEST FORAGES?
FORAGE MOISTURE DETERMINES THE
APPROPRIATE HARVEST METHOD
GREEN CHOP
• Forage is chopped and fed directly from field
• Works well with legumes, forage sorghums,
and corn
• Advantages
– Minimal harvest losses
• Greater harvest efficiency than grazing
– No fencing required
– Reduces bloat problems with legumes
• Limitations
–
–
–
–
No storage
Fuel, equipment and wagon requirement
Weather dependence
Difficulty in controlling maturity.
HAY
• Forage harvested at a moisture level of 15% or less
• Factors affecting nutritional quality
– Forage species
– Maturity
– Losses during harvest, storage and feeding
Step
Loss, % of standing DM
Mowing
1 to 6
Raking
5 to 20
Swathing with conditioner
1 to 10
Plant respiration
2 to 16
Baling
1 to 15
Storage,
Outside
5 to 30
In-barn
2 to 12
Transporting
1 to 5
Feeding,
With feeder
1 to 10
Without feeder
2 to 45
Total losses
10 to 80
LOSSES IN HAY HARVEST
• Leaf loss
– Compared to stems, leaves contain:
• More protein, sugars, carotene, and minerals
• Less NDF and ADF
– Loss greater from legumes than grasses
– Loss increased by:
• Raking at higher DM concentrations
• Baling with a large round baler compared to square
bales
• Rain, particularly if the forage is relatively dry
• Cell respiration
– Metabolism of plant soluble carbohydrates by
plant enzymes at moisture concentrations above
48%
– Losses range from 2 to 16% of dry matter
– Losses affected by rate of drying
• Heat damage
– Occurs when hay is stored at moisture
concentrations greater than 18%
– Stimulates growth of aerobic bacteria and mold
• Metabolizes soluble carbohydrates
• Causes heating
– Temperatures > 120oF causes heat-damage to proteins
– Temperatures > 160oF may cause spontaneous
combustion
• Results in decreased net energy concentration and protein
digestion
• Leaching
– Loss of soluble nutrients in rainfall or snow melt
– Occurs during:
• Rainfall during prior baling
• Outside storage of bales
– Losses greater from legumes than grasses
HAY MANAGEMENT TO MAXIMIZE QUALITY
• Mowing
– Goal
• To mow at high quality and to maximize rate of drying
– Managing for forage quality
• Stage of harvest
Plant stage
Crop
High quality
Maximum yield
Legumes
Late bud
Mid-bloom
Grasses
Boot stage
Flowering
Cereal grains
Boot stage
Soft dough
• Timing of harvest
– Mowing at end of day will have higher concentration
of sugars than mowing in morning
– Rate of drying
• Drying process
– 80 to 60% moisture
– 60 to 40% moisture
– 40 to 15% moisture
• Rapid drying desirable
-
Rapid
Slow
Very slow
– Limits cell respiration
– Reduces rain damage risk
• Factors affecting drying rate
– Weather
» Prefer high temperatures and low humidities
– Timing of mowing
» Mowing early in day maximizes solar drying
– Wide, thin windrows
» Exposure to wind and sunlight
– Tedding hay
» Fluffs windrows
– Mechanical conditioning
» Cracks stems to release moisture
– Chemical conditions
» Potassium or sodium carbonate
• Applied at 5 to 7 lb / acre
• Reduces drying time by ½ day
• Effective on legumes, but not grasses
WHY CONCERNED ABOUT RAIN DAMAGE?
• Probability of 3 days without rain in Iowa
– May - 26%
– June - <40%
– July - <50%
• Rain damage
– Leaf loss
– Decreased concentrations of sugars, protein,
vitamins, and soluble minerals
Alfalfa, Bud:
Rainfall, in
No rain
1”
1.65”
2.5”
% DM loss
Leaf loss
7.6
13.6
16.6
17.5
Respiration &
leaching
2.0
6.6
30.1
36.9
Total
9.6
20.2
46.6
54.4
• Windrowing
– Goal is to get forage into a form for continued
aeration and baler pickup with minimal leaf loss
– Done with a rake or windrower
– Factors
• Species
– Alfalfa, 15-25% loss
– Grass, 5-10% loss
• Moisture level
– Avoid windrowing before forage is above 50% moisture
– Avoid windrowing when forage moisture is <35%
BALING
• Small square
–
–
–
–
–
–
60 – 100 lb
1 to 5% harvest loss from alfalfa
Easily handled
Marketable
Labor intensive
Requires barn storage
• Large round bales
– 800 – 2,000 lb
– 5 to 30% harvest loss from alfalfa
• Affected by field speed, windrow size, chamber rotation speed,
and wrapping rotations
–
–
–
–
Requires equipment for handling
Less marketable than rectangular bales
Less labor than small rectangular bales
May be stored outside or inside
–
–
–
–
–
–
600 – 3,000 lb
Lower harvest losses than round bales
Requires equipment of handling
Marketable
Less labor than small rectangular bales
Better stored inside than round bales
• Large square
FACTORS AFFECTING HAY STORAGE LOSSES
• Inside storage vs outdoors
– Under Iowa conditions
• Necessary for small rectangular bales
• Preferred for large rectangular bales
• Depends on hay price and use for large round bales
– Storage losses from large round bales
EFFECTS OF WEATHERING ON LARGE
ROUND BALES STORE OUTSIDE
• Decreases
– DM weight and
concentration
– DM and protein digestibility
• Increases
– NDF, ADF and ADIN
• Greatest effects on outside
of bales
Composition of hay after 4
to 10 months of storage
70
60
% of DM
Weathering effects
50
40
30
20
10
0
CP
NDF
ADF
Dig
MANAGEMENT PRACTICES TO REDUCE
STORAGE LOSSES FROM LARGE ROUND
BALES STORED OUTSIDE
• Baling
•
•
•
•
•
•
– Moisture level < 18%
– Dense package
– Net wrapping
Drained surface (Crushed rock, pallets etc)
Plastic cover
Pyramid stack with plastic cover
Plastic sleeve or wrap
Place bales end-to-end in rows
Place bale rows in a north/south direction with a
minimum of 3 ft between rows
• Place bales rows up and down slopes of hills
• Do not place bales in shaded areas
PRICE FOR BARN STORAGE TO PRESERVE DM
OR DIGESTIBLE DM OF LARGE ROUND BALES
COMPARED TO OTHER STORAGE METHODS*
$10.50/sq. ft.
$3.00/sq. ft.
* Doesn’t consider changes in hay quality.
FACTORS AFFECTING HAY STORAGE
LOSSES (Continued )
• Harvest moisture
– Excessive hay moisture
• Increased loss of DM and
nutrients during storage
– Decreased DM
digestibility and carotene
content
– Increased NDF, ADF, and
ADIN concentrations
• Losses greatest in large bales
– Unable to transpire
moisture
– Worsens weathering
damage to bales stored
outdoors
– Problems worse in bales
stored in barn or under
plastic
• May result in spontaneous
combustion
70
60
50
40
30
20
10
0
CP, DM
NDF, DM
ADF, DM
Dig DM, %
ADIN, %N
Low moisture = 15%; High moisture=19%
HAY PRESERVATIVES
• Types
– Propionic acid
• Application rates
– Hay moisture
20-25%
25-30%
30-35%
Lb/ton hay
10
20
30
• Effective if properly used
– Others
• Sodium diacetate at 5 lb/ton for hay up to 25% moisture
???
• Anhydrous ammonia at 60 lb/ton
– Effective fungicide
– Do not use on high quality hay
• Salt (NaCl)
– No Controlled studies
USE OF PROPIONIC ACID AS A HAY
PRESERVATIVE
• Must apply correct amount of active ingredient
• Must get uniform application
• Advantages
– Allows barn-stored hay to be harvested at higher
moisture concentrations
• Less leaf loss
• Reduces rain risk
• Limitations
– Cost
– Water soluble
– Corrosive
• May be controlled by using ammonium propionate
FACTORS AFFECTING FEEDING LOSSES
OF HAY
• Form
– Ground
• Minimizes forage loss
• Allows for hay feeding
in total mixed rations
(TMR)
• Requires some type of
bunk for feeding
– Long
• Hay losses affected by
feeder type
• Adequate space
around feeder
– 900 lb hay = 30
cows/day
– Usually space for 10
cows to each at once
around round bale
feeder
Hay wasted,%
35
30
25
20
15
10
5
0
Hay wasted,%
• Length of access to feeder
– For gestating beef cows fed moderate quality
alfalfa-orchardgrass hay, compared to 24
hour/day access to large round bales in bale
feeders:
• 12 hour access reduced hay disappearance by 4.4%
• 8 hour access reduced hay disappearance by 17.6%
• 4 hour access reduced hay disappearance by 37.2%
– But 4 hour access also reduced cow weight gain
– Recommend limiting access to bale feeders to 6
to 8 hours
• Assumes moderate quality hay
• Adequate feeder space
HAY GRADES
Composition
Alfalfa (<10% grass)
Hay
grade
ADF
NDF
Relative
feed
value
Grass
TDN
CP
CP
% DM
Supreme
<27
<34
>185
>62
>22
-
Premium
27-29
34-36
170-185
60.5-62
20-22
>13
Good
29-32
36-40
150-170
58-60
18-20
9-13
Fair
32-35
40-44
130-150
56-58
16-18
5-9
Utility
>35
>44
<130
<56
<16
<5
HAY GRADES
Physical description
Maturity
Grade
Alfalfa
Grass
Leafiness
Stems
Color
Other
Supreme
Prebloom
-
Extra
leafy
Fine soft
stems
Excellent
Damage
free
Premium
Prebloom
Pre-head
Extra
leafy
Fine
stems
Green
Damage
free
Good
Early to
midbloom
Early
head
Leafy
Fine to
medium
stems
Slight
discolored
Damage
free
Fair
Mid to
late
bloom
Headed
Moderate
Generally
coarse
Light
browm
Light
damage
Utility
Mature
seed
pods
Mature
head
Low
Coarse
Dark
brown
Excess
damage,
weeds,
mold
MATCH HAY QUALITY TO ANIMAL
NUTRIENT REQUIREMENTS
200
Relative Feed Value
Supreme
180
Premium
Good
160
140
Fair
120
Utility
100
Beef cows
Ewes
Beef feedlot
(Growing)
Growing
cattle &
replacement
heifers
Lambs &
working
horses
Dairy cows
EFFECTS OF HAY GRADES ON HAY PRICE
Rock Valley, IA on February 10, 2012
Alfalfa
Grade
Small
square
Large
square
Grass
Large
round
Small
square
Large
square
Large
round
$/ton, as-fed
Supreme
230
Premium
230
205
185
170
Good
165
175
165
125
145
115
120
Fair
140
95
Utility
115
75
Corn
stalks
45