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HARVESTED FORAGES Green Chop and Hay
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WHY HARVEST FORAGES?
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FORAGE MOISTURE DETERMINES THE APPROPRIATE HARVEST METHOD
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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.
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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 Without feeder 2 to 45 Total losses 10 to 80
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LOSSES IN HAY HARVEST Leaf loss Cell respiration
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
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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
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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
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Rapid drying desirable Factors affecting drying rate
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
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WHY CONCERNED ABOUT RAIN DAMAGE?
Probability of 3 days without rain in Iowa May % 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
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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%
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BALING Small square Large round bales Large 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 Better stored inside than round bales
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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
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EFFECTS OF WEATHERING ON LARGE ROUND BALES STORED OUTSIDE
Weathering effects Composition of hay after 4 to 10 months of storage Decreases DM weight and concentration DM and protein digestibility Increases NDF, ADF and ADIN Greatest effects on outside of bales
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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
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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.
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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 Low moisture = 15%; High moisture=19%
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HAY PRESERVATIVES Types Propionic acid
Application rates Hay moisture Lb/ton hay 20-25% 25-30% 30-35% 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
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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
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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
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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
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HAY GRADES Composition
Alfalfa (<10% grass) Grass Hay grade ADF NDF Relative feed value TDN CP % DM Supreme <27 <34 >185 >62 >22 - Premium 27-29 34-36 20-22 >13 Good 29-32 36-40 58-60 18-20 9-13 Fair 32-35 40-44 56-58 16-18 5-9 Utility >35 >44 <130 <56 <16 <5
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HAY GRADES Physical description
Maturity Grade Alfalfa Grass Leafiness Stems Color Other Supreme Pre-bloom - Extra leafy Fine soft stems Excellent Damage free Premium Pre-head Fine stems Green Good Early to mid-bloom Early head Leafy Fine to medium stems Slight discolored 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
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MATCH HAY QUALITY TO ANIMAL NUTRIENT REQUIREMENTS
Supreme Premium Good Fair Utility
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EFFECTS OF HAY GRADES ON HAY PRICE Rock Valley, IA in late August, 2012
Alfalfa Grass Grade Small square Large square Large round $/ton, as-fed Supreme 270 288 250 255 212 Premium 240 260 220 190 Good 230 210 142 165 Fair 140 125 127 137 Utility 90 112 Corn stalks 67 102
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