HARVESTED FORAGESGreen Chop and Hay

pp. 250-253

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 DMMowing 1 to 6Raking 5 to 20Swathing with conditioner 1 to 10Plant respiration 2 to 16Baling 1 to 15Storage, Outside 5 to 30 In-barn 2 to 12Transporting 1 to 5Feeding, With feeder 1 to 10 Without feeder 2 to 45Total 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 stageCrop High quality Maximum yieldLegumes Late bud Mid-bloomGrasses Boot stage FloweringCereal 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 - Rapid– 60 to 40% moisture - Slow– 40 to 15% moisture - Very slow

• Rapid drying desirable– 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, inNo rain 1” 1.65” 2.5”

% DM lossLeaf 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

• Large square– 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

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 STORED OUTSIDE

Weathering effects• 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

Weathered

Core0

10

20

30

40

50

60

70

CPNDFADFDig%

of D

M

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

Harvest

Low M

oisture

Harvest

High M

oisture

9 mo St

orage Lo

w Moist

ure

9 mo St

orage High

Moist

ure0

10203040506070

CP, DMNDF, DMADF, DMDig DM, %ADIN, %N

Low moisture = 15%; High moisture=19%

HAY PRESERVATIVES• Types

– Propionic acid • Application rates

– Hay moisture Lb/ton hay20-25% 1025-30% 2030-35% 30

• Effective if properly used on bales stored indoors– 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

05

101520253035

Hay wasted,%

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 GRADESCompositionAlfalfa (<10% grass) Grass

Hay grade

ADF NDF Relative feed value

TDN CP CP

% DMSupreme <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 9-13Fair 32-35 40-44 130-150 56-58 16-18 5-9

Utility >35 >44 <130 <56 <16 <5

HAY GRADESPhysical description

MaturityGrade Alfalfa Grass Leafiness Stems Color Other

Supreme Pre-bloom

- Extra leafy

Fine soft stems

Excellent Damage free

Premium Pre-bloom

Pre-head Extra leafy

Fine stems

Green Damage free

Good Early to mid-

bloom

Early head

Leafy Fine to medium stems

Slight discolored

Damage free

Fair Mid to late

bloom

Headed Moderate Generallycoarse

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

Beef c

owsEwes

Beef fe

edlot (G

rowing)

Growing catt

le & re

placem

ent h

eifers

Lambs & w

orking horses

Dairy cows

100120140160180200

Rel

ativ

e Fe

ed V

alue

Supreme

Premium

Good

Fair

Utility

EFFECTS OF HAY GRADES ON HAY PRICERock Valley, IA in late August, 2012

Alfalfa GrassGrade Small

squareLarge

squareLarge round

Small square

Large square

Large round

$/ton, as-fedSupreme 270 288 250 255 212Premium 240 260 220 190 190

Good 230 210 142 165Fair 140 125 127 137

Utility 90 112Corn stalks

67 102