Making The Best Use of Alfalfa in Dairy Rations

Transcription

1 Making The Best Use of Alfalfa in Dairy Rations Dr. Dan Undersander University of Wisconsin Effect of forage quality on % fat-corrected milk production at four concentrate levels rrected milk /day) % fat cor (lb/ Prebloom Early bloom Mid bloom Full bloom Alfalfa maturity stage % grain in ration % 37% 5% From Kawas et al., 1989 Influences on corn silage Corn Silage Variation Less than half of variation in corn silage digestible energy due to genetics (non-bmr). Do not assume traits like soft kernel, digestible starch, etc., will compensate for poor management -- They do not. Have one shot to get corn silage right. Haylage versus Corn Silage lbs $ Lbs $ Corn silage 1 Haylage 11 Corn 1.9 $ $1.3 SBM.1 $.7.8 $1.15 $.57 $.7 Corn price $./bu Bottom Line lbs $ lbs $ 3 milk/ton 17 3 CP 175 RFV 17 3 milk/ton CP 15 RFV Corn SBM $.3 $3.5 Or, $1. lowered forage fed by. pounds, but that dry matter still cost $33/ton dry matter 1

2 Targeted Byproduct Usage lbs $ lbs $ lbs $ Haylage Corn Sil Corn SBM Dist Forage Quality Crucial Low quality forage reduces milk production Low quality cannot be over come Low quality forage raises cost of rations Distillers has net cost of $93/ton when replacing corn silage or $8/ton when replacing haylage. Steps to High Quality Alfalfa for Optimal Use in Dairy Rations Cut on time Cut at.5 to 3.5 inch height Minimize ash content Put in wide swath Minimize heating Rapid feedout Rate of Alfalfa Forage Quality Change per Day Component Mean Crude Protein, % DM -.5 Acid Detergent Fiber, % DM.3 Neutral Detergent Fiber, % DM.3 Neutral Detergent Fiber Digestibility, % NDF -.3 Source: Undersander, 9 unpublished Produce Quality Forage Cut for forage quality desired Quality changes daily Can only preserve harvested quality, not improve

3 Relationship between yield and forage quality Cutting Decisions - 1 st cut Forage Quality Stick Take first cutting by quality - Not stage of maturity Cutting Decisions - 1 st cut Forage Cutting Height vs Yield by Cutting Forage Quality Stick Predictive Equations of Alfalfa Quality (PEAQ) protocol 1- WI Choose representative one square foot area of field 1) Determine stage of most mature stem in area using criteria (in box at right): late vegetative - stem over 1 inches tall no visible buds or flowers bud - 1 or more nodes with visible buds, no flowers or seed pods flower - 1 or more nodes with open flowers, no seed pods ) Measure the height of tallest stem in ft area (from soil surface) 3) Based on the most mature and tallest stem, use chart estimate NDF or RFV ) Repeat the above procedure in 5 to 1 areas of field to obtain field NDF or RFV ns DM/ac) Yield (to.5 Cut 1 Cut. Cut 3 Cut Cut Height (inches above soil) Clark and Wood County, WI AM vs PM Cutting Why should ash content be a concern? Beneficial if good drying conditions Hay should dry to less than % moisture by nightfall Ash provides minerals to the diet, but no calories (i.e. energy). Takes the place of nutrients on almost a 1:1 basis. Ash content above that contained in plant is dirt contamination 3

4 Ash Content of Forage Samples Possible Causes of Higher Levels of Ash in Forages Average internal ash content of alfalfa is to 8% Average internal ash content of grass is 5 to % Remainder of ash is dirt! Ash Content of Forage Samples, UW Marshfield Lab Type Statistic % Ash Haylage Avg 1.3 Max 18. Min 5.7 Hay Average 1.3 Max 17. Min 8.8 Disc mower knives angled Forage cut too close to ground Windrow lays on ground Raking to scrape ground Merging swaths/windrows will minimize ash content while improving harvest efficiency Minimize wheel traffic damage Managing to Reduce Wheel Traffic Loss No traffic Traffic Minimize driving on field Use smallest tractor for equipment Merge windrows where possible Go to larger equipment Take most direct route to edge of field Make road to drive on Managing to Reduce Wheel Traffic Loss Minimize driving on field Do driving on field soon after harvest Manage to dry forage quickly Harvest for haylage or baleage Use preservative and harvest wet hay Use of duals not recommended Apply manure quickly after cutting Put hay into wide swath Dries faster Higher TDN

5 Sequence of Drying Forages Effect of wide swath on drying rate 8% Figure a. Field 5 N Arlington Research Station May 9, 3, 31, 7 Stomatal openings 9 wide swath vs narrow swath drying rate ture Moist % Conditioning Weather regulated Osmotic & Cell forces percent moisture wide swath narrow swath 3 % Time 1 9am Day 1 pm Day 1 5pm Day 1 9am Day pm Day 5pm Day 9am Day 3 pm Day 3 time Maximum swath width versus cutting width Hay Preservation Results of Malliard Reaction th Width (%) Maximum Swa Cutting Width (in.) Change, Percentage Units Dig NDF Dig CP Dig NFC Heating Degree Days > 8F Hay Preservation Results of Malliard Reaction Stewart Alfalfa Haylage Bunker TDN = dnfc + dcp+.5*fa + dndf - 7 Wall Corner Top of Face Units Change, Percentage U Dig NDF Dig CP Dig NFC TDN Bottom of Face -1 Heating Degree Days > 8F Source: Bill Mahanna 5

6 Stewart Alfalfa Haylage Bunker Why is Density Important? Wall Corner Top of Face Bottom of Face Silage Density Dry Matter Loss, (lbs DM/ft 3 ) 18 days (%) Data from Ruppel, 199 Source: Bill Mahanna Packing Density Six-inch Layers Heavy Tractors With added weight Wheels well lugged, high tire pressure Progressive wedge method Drive over entire surface Multiple passes Take Home Messages Oxygen movement into silage face Harvest in the recommended range of dry matter ( 3-% ) Pack to achieve bulk density of at least lbs AF /ft 3 Plastic Cover O = % Zone of Heating CO ~ 5-% O Diffuses Into Forage O = 1% CO Diffuses Out CO =.% Feed Out Face Longitudinal Cross Section of Bunker Silo

7 3 ft (days). Time to Remove Time to Remove 3 ft vs Removal Rate Removal Rate (in/day) Mold on wrapped bales Minimize Feedout Losses Air diffuses 3 inches into face of tube or bunker Mold reduces feed intake, Feed 1 inches from face per day Steps to High Quality Alfalfa for Optimal Use in Dairy Rations Cut on time Cut at.5 to 3.5 inch height Minimize ash content Put in wide swath Minimize heating Rapid feedout 7