HCS412 Forage Crops
Harvest
Management (Ch 16 pg 377-388) (Dr Mark Sulc)
Harvest decisions influence:
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Yield (too many or too few harvests can reduce yield) |
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Forage quality (delayed harvest can reduce quality) |
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Stand persistence (too many harvests can reduce plant reserves and reduce persistence) |
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Insect damage (harvests can accelerated or delayed because of insect damage) |
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Disease infestation |
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Field and storage losses (too dry, too wet, rain - all increase losses) |
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PROFIT (all the above affect profit) |
Effect
of Harvest Timing on Root Reserves in Alfalfa (Fig 4.6 pg 88)
Root Reserves in 4-cut System (see Fig 4.8 pg 90 for a 2-cut system)
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Seeding year Harvest depends on seeding date
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First Harvest Timing in Established Stands
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Summer Harvest Timing
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Fall Harvest Cautions
Fall Harvest Tips
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| Stage | CP | ADF | NDF | RFV |
| Late vegetative | 23 | 28 | 38 | 164 |
| Bud | 20 | 29 | 40 | 154 |
| Early bloom | 18 | 31 | 42 | 144 |
| bloom | 17 | 35 | 46 | 125 |
| Full bloom | 15 | 37 | 50 | 112 |
Need to know:
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Energy Requirements: Animals with high energy requirements need high quality forage (e.g. lactating animals) |
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Intake Potential: Animals that have to eat large amounts of feed need high quality forage |
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Amount of forage fed: Forage quality not that important for animals fed low forage diet (e.g. feedlot steers) |
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Economics Cost of feed relative to value of product. A high producing dairy cow generates $3000/yr in gross income, a gestating beef cow generates $450/yr. |
Beef cows (TDN 56 to 62%)
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ADF
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NDF
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CP
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| Grass |
37-42
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57-69
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10-13
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| Alfalfa |
33-39
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43-50
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17-20
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| Mix |
35-40
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48-55
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15-18
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Note: high fiber = low TDN
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CP
less than 10% tend to reduce intake |
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Most beef cows require less than 12% CP (high lactation breeds in first 3 months need 12-14% CP). CP fed in excess is simply excreted in urine (no value to the cow) |
Average producing cow (~18,000 lb/yr)
High producing and early lactation
Forages lower in quality reduce intake and usually result in lower milk production
Difficult to balance diets to maintain good intake with low quality forages
Assessment of Moisture Content of Hay - A Practical Guide
| % Moisture Condition | ||
| 30 - 40% | Leaves begin to rustle and do not give up moisture unless rubbed hard. Juice easily extruded from stems using thumbnail or knife or with difficulty by twisting in hands. | |
| 25 - 30% | Hay rustles - a bundle twisted in the hands will snap with difficulty, but should extrude no surface moisture. Thick stems extrude moisture if scraped with thumbnail. | |
| 20 - 25% | Hay rustles readily - a bundle will snap easily if twisted, leaves may shatter, a few juicy stems remain. | |
| 15 - 20% | Swath-made hay fractures easily, snaps easily when twisted, juice difficult to extrude. | |
Reproduced from Hoard's Dairyman 132. 1987.
1 = Vegetative (stems have no buds or flowers)
2 = Early bud; 1-33% stems have buds
3 = Mid bud; 34-65% stems have buds
4 = Late bud; 66-100% stems have buds (no flowers present)
5 = Early flower; 1-33% stems have open flowers
6 = Mid flower; 34-65% stems have open flowers
7 = Late flower; 66-100% stems have open flowers (no seed pods present)
8 = Post flower; stems have pods or seeds
Alfalfa Stem Staging (from Kalu and Fick, 1981)
0 = Stems < 16 cm, no buds or flowers
1 = Stems 16-30 cm, no buds or flowers
2 = Stems >30 cm, no buds or flowers
3 = 1-2 nodes with visible buds, no flowers
4 = 3 or more nodes with buds, no flowers
5 = 1 node with an open flower, no seed pods
6 = 2 or more nodes with open flowers, no seed pods
7 = 1-3 nodes with green seed pods
8 = 4 or more nodes with green seed pods
9 = Nodes with mostly brown mature seed pods
Grass Maturity Visual Rating (from Moore et al., 1991)
VE = Emergence of first leaf
V1 = First leaf collared
V2 = Second leaf collared
Vn = Nth leaf collared
E0 = Onset of stem elongation
E1 = First node palpable/visible
E2 = Second node palpable/visible
En = Nth node palpable/visible
R0 = Boot stage
R1 = Inflorescence emergence/first spikelet visible
R2 = Spikelets fully emerged, but peduncle not emerged
R3 = Inflorescence emerged and peduncle fully elongated
R4 = Anther emergence/anthesis
R5 = Post-anthesis
S0 = Seed caryopsis visible
S1 = Milk stage
S2 = Soft dough
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