Principles of Silage Fermentation and Management L. E. Chase and T. R. Overton Dept. of Animal Science Cornell University

What is Silage? z“The feedstuff resulting from the anaerobic preservation of moist forage or other feeds by the formation and/or addition of acids” zDr. M. E. McCullough

Forage Goals     

Silage Fermentation (Dr. Limin Kung, Jr.) sugars lactic acid pH Days of Ensiling

Common Measurements of Fermentation End Products ItemComments DM(+) can dictate type, speed, and extent of fermentation pH(+) measures strength of acid in sample Ammonia(–) indicator of excessive protein degradation

Common Measurements of Fermentation End Products ItemComments Lactic acid (+) strongest acid (–) weak antifungal Acetic acid (+) very antifungal Butyric acid(–) a weak acid Propionic acid(+) very antifungal

Microbes Good bugs Lactic acid bacteria heterofermentative homofermentative Bad bugs Fungi yeasts molds Enterobacteria Clostridia

Silage Fermentation Phases

Nitrogen Compounds in Fresh Forage and Silage Oshima et.al.,1979

Silage DM and NPN Muck, 1987

Excess Oxygen Has Negative Effects on the Ensiling Process l slower fermentation l excess protein breakdown l growth of undesirable aerobic organisms l excess heating (silo and feed bunk) l more nutrient and DM loss (10- 25%)

How Dry Matter Content Affects Fermentation DM% 55% Too Dry run off poor packing, air clostridial growth slow fermentation protein degradation molding/heating excessive fermentation heat damaged protein DM and energy losses Dr. Limin Kung, Jr.

Cumberland Valley Analytical Services

Aerobic Deterioration zOccurs primarily in feedout period zSignals are heating and spoilage zInitiated by yeasts and molds which oxidize the preservation acids zEquals energy loss and potential DMI depression

Clostridial Silage zSpore forming bacteria zAre normally anaerobic zLow DM levels ( <30% ) increase risk zpH is usually > 5 zHigh ammonia & butyric levels zDepresses dry matter intake

What Steps Are Needed? zStart = Forage standing in field zEnd = Forage consumed by the cow zWhat do we need to manage?

Silage Triangle Sugar Bacteria Acids H 2 0

Health effects of a fermentation gone awry z1200 cow NY dairy zDecreasing milk production zIncreasing metabolic disorders

Alfalfa 1st 99 CowsInconsistent… Milk66 lbs % ADF39.9 NDF46.6 CP20.4 DM26.5 pH5.7 NH3 -N,33 % of total N Lactic.8 Acetic3.5 Butyric4.4 Total VFA10.1 Alfalfa 3rd 99 BAR 72 lbs % < NY Dairy days

Key Points zHarvest at correct moisture & maturity zFill FAST !! zPack, pack, pack, pack, etc. zSeal with a cover zConsider a bacterial inoculant zFeedout = tight, straight face zFeed fast to minimize reheating