Silage Forage Quality Using Inoculants and Packing Dr. Dan Undersander University of Wisconsin
Inoculants Silage additives whose main ingredients are lactic acid producing bacteria
Purpose of Inoculants Lactic acid bacteria are the group of bacteria that ferment sugars in the crop and help preserve it. Help insure that the fermentation goes in the direction that you want it. Drop ph rapidly Reduce heating loss To reduce protein solubilization Prevent growth of undesirable microbes
Different Types of Inoculants Traditional homofermentative types: Lactobacillus plantarum, L. casei, Pediococcus species, Enterococcus faecium Lactobacillus buchneri, a heterofermenter Combination of homofermenters with L. buchneri
Homofermenter vs. Heterofermenter Homofermenter 1 6-C Sugar 2 Lactic Acid Heterofermenter 1 6-C Sugar 1 Lactic Acid + 1 Acetic Acid + CO 2 1 6-C Sugar 1 Lactic Acid + 1 Ethanol + CO 2 1 Lactic Acid 1 Acetic Acid + CO 2 (L. buchneri, not all heteros)
End Product Comparison Lactic acid - strong acid; weak spoilage inhibitor; fermented in rumen Acetic acid - weak acid; good spoilage inhibitor; not fermented in rumen Ethanol - neutral; poor spoilage inhibitor; partially fermented in rumen Carbon dioxide - lost dry matter
Homofermentative Inoculants - Reality When they work: High lactic acid content, low other products Low ph Improved DM recovery (5-6%) Better animal performance (3-5%) Mixed effect on bunk stability Improves stability of alfalfa silage Negative effect on corn silage
Homofermentative Inoculants - Results ph Lower, but not all the time Works more often in hay crop than whole-grain silages % Trials with lower ph 70 60 50 40 30 20 10 0 (Muck and Kung, 1997)
Homofermentative Silage Inoculants ROI Improved DM recovery, 2-3% on average Treat 1000 tons as fed: $1000 Save 25 tons as fed If each ton saved is worth $60 or more, ROI = 1.5 Improved animal performance 3-5% when effective Assume 3 lbs. milk/cow/day when effective If effective 50% of the time, 1.5 lbs. milk/cow/day With milk at $16 per 100 lbs., $0.24 extra income/cow/day If cow is eating 60 lbs. silage as fed/day, then inoculant cost is $0.03/cow/day.
Aerobic Stability Problems Is the problem a management problem that can be solved without an additive? Corn Silage: L. Buchneri good alternative to propionic acid or anhydrous ammonia Safer to handle Cost competitive Similar effects on DM recovery & animal performance with all three additives If multiple silos/bunkers, use only on the silage to be fed in warm weather
Aerobic Stability Problems Is the problem a management problem that can be solved without an additive? Alfalfa and grass Above 55% moisture, stability problems are almost always related to management issues Below 55% moisture, you have a number of options: Feed out in winter Homofermentative inoculants for sporadic warm weather issues should make small improvements in stability L. buchneri or combination of products for more consistent warm weather issues.
Issues with L. buchneri Slower growth than L. plantarum, takes 45 to 60 days storage time before having much effect Not an answer to heating problems with immature silage; propionic acid is the best solution. Adding at feeding no benefit.
Phases of silage fermentation process 100 80 60 40 oxygen Bacteria ph oxygen 20 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Days Aerobic phase Feedout phase
Inoculant application Apply 100,000 colony forming units (cfu) per gram of fresh forage. Should be applied as liquid for better coverage Need good coverage for inoculant to be successful Should be applied at chopper, not bunker Inoculant does not move in silage once applied.
Take home Inoculation with bacterial inoculants improves both initial fermentation and preserved on feedout Lactobacillus buchneri helpful when less than optimum management. Inoculant must be applied for good coverage.