QUESTIONS AND ANSWERS ON LACTOBACILLUS BUCHNERI 40788, A NEW MICROBIAL INOCULANT THAT IMPROVES THE AEROBIC STABILITY OF SILAGES
Kung, Jr. and Christina Taylor
University of Delaware
|1.||What is aerobic stability?|
stability” describes the ability of a silage to remain stable (and not
spoil) when exposed to air. A
simple method to measure aerobic stability is to expose silage to air and
measure the generation of heat. Heat
is produced from spoilage organisms (usually yeasts) that degrade the
nutrients in silage. As an
example, good quality silage that is stable for 50 hours is better than
one that spoils after 10 hours of exposure to air.
|2.||Why should we be concerned about the aerobic stability of silage?|
silages are exposed to air, yeasts can degrade lactic acid, which
increases the pH and leads to spoiling.
Spoiled silage is especially bad when fed to ruminants because it
is low in nutritive value and dry matter intake can be severely depressed.
Aerobic spoilage in the silo may also lead to the production of
mycotoxins, which can result in reduced animal performance.
|3.||When is aerobic stability of silages a problem?|
heat occurs from the natural process of fermentation and this should not
be confused with heating from spoilage.
However, extensive and prolonged heating during the early period of
ensiling may be a result of excess air trapped in the forage mass.
Warm weather and exposure to air, encourages the growth of spoilage
microbes in silage.
|4.||Are some crops more prone to aerobic spoilage than others?|
Silages that contain large amounts of starch (e.g. corn silage and
barley silage) tend to spoil more readily than other silages but alfalfa
and grass silages can also readily spoil.
Silages that are very dry also tend to spoil more quickly when
exposed to air than those with a high moisture content.
High moisture corn also tends to spoil rapidly when exposed to air.
|5.||What management factors can improve the aerobic stability of silages?|
to the proper moisture content for the specific crop and silo, correct
chop length, rapid filling, good packing, and immediate sealing of silos
will help to prevent excess air from spoiling silage.
Good bunker face management and feedout rate can also help to keep
silages from spoiling.
|6.||What silage additives can help to improve the aerobic stability of silages?|
propionic acid-based additives applied at the time of ensiling at 2 to 4
lb. per ton of fresh forage can help to improve the aerobic stability of
silages. Preservatives that
can be added to a TMR at the time of feeding are also available, but if
silage is spoiling to a considerable extent in the silo, adding these
products only at feedout may not be the best option.
Anhydrous ammonia can be used on corn silage to improve its aerobic
stability, but ammonia is extremely hazardous to use.
microbial inoculants improve fermentation but do not consistently improve
the aerobic stability of silages. However,
several new products contain microbes that specifically improve the
aerobic stability of silages. One
of these microbes, Lactobacillus
buchneri 40788 has markedly improved aerobic stability in silages.
|7.||How does Lactobacillus buchneri 40788 improve the aerobic stability of silages?|
most microbes found in silage inoculants, Lactobacillus
buchneri 40788 is a heterolactic microbe that produces high
concentrations of acetic acid, and sometimes lesser amounts of 1, 2
propanediol, propanol, and propionic acid.
Other antifungal compounds may also be produced as well.
Both acetic and propionic acid are more effective at reducing the
growth of yeasts and molds than is lactic acid.
Thus research studies have shown that silages treated with Lactobacillus
buchneri 40788 remain unspoiled for much longer periods of time than
untreated silage when exposed to air.
|What kind of improvement in aerobic stability is expected from treatment with Lactobacillus buchneri 40788?|
absolute number for improvement in aerobic stability from any additive is
difficult to give because so many factors can affect the movement of air
into the silage mass. In
addition, silage can begin to spoil days before it is actually placed in
the feed bunk. However, in
research studies, silages treated with Lactobacillus
buchneri 40788 have taken between fifty to several hundred hours
longer to spoil than untreated silage.
|9.||Does Lactobacillus buchneri 40788 work on all types of silages?|
Research has shown that Lactobacillus buchneri 40788 can improve the aerobic stability of
corn, barley, ryegrass, alfalfa silage, and wheat silage. Lactobacillus buchneri 40788 has also improved the aerobic stability
of high moisture corn.
|Should I be concerned about dry matter losses in the silo because Lactobacillus buchneri 40788 is a heterolactic acid bacteria?|
not. Research conducted with Lactobacillus
buchneri 40788 has shown that sometimes the loss of dry matter in the
silo is slightly more than in untreated silage.
However, these losses were small.
The potential for sparing greater spoilage losses during storage
and feedout out weighs the small losses that might be incurred as a result
of the fermentation.
|Should I be concerned that the high concentrations of acetic acid in silages treated with Lactobacillus buchneri 40788 might reduce intake?|
not. In some past
studies (not involving Lactobacillus
buchneri 40788), silages with high concentrations of acetic acid have
been associated with depressions in intake.
However, there is no direct evidence that acetic acid itself is
responsible for this finding. In addition, acetic acid produced by Lactobacillus buchneri 40788 occurs via a pathway that is different
from that used by other heterolactic acid bacteria. To date, research studies have shown that feeding silages
treated with Lactobacillus buchneri 40788
does not reduce the dry matter intake of dairy cows (three lactation
studies) or sheep (one study).
|12.||What is the proper application rate for Lactobacillus buchneri 40788?|
research has shown that in typical crops and conditions in the U.S., Lactobacillus
buchneri 40788 must be applied at a rate to achieve about 400,000
colony forming units per gram of wet forage.
This is higher than the recommended application rate of 100,000
colony forming units per gram of wet forage for traditional microbial
|13.||Are all Lactobacillus buchneri the same?|
The data reviewed in this article has been generated specifically
with the strain Lactobacillus
buchneri 40788 and should not be considered generic to all Lactobacillus
|14.||When should one consider using Lactobacillus buchneri 40788?|
|Lactobacillus buchneri 40788 should be used in cases where aerobic
stability is a problem. For
example, bunk, pile or pit silos with large exposed surfaces are good
candidates for treatment with Lactobacillus
buchneri 40788. If
spoiling silage occurs only during warm weather, treating only the portion
of silage that would be fed during that time of the year may be an option
(this may be more difficult to do in a bunk rather than tower or bag silo.
Silage moved from one silo structure to another and or silage exposed to
air for several days before feeding should be considered for treatment
with Lactobacillus buchneri
|How would I know if the inoculant I am buying has Lactobacillus buchneri 40788 in it?|
|Any product that contains Lactobacillus buchneri strain 40788 will identify the strain as
40788 on the list of ingredients on the product labelling.
If you are looking at product literature then, the 40788
designation to be featured both in the text and in the product description
|L. Kung, Jr. is a Professor in the Department of Animal & Food Science at the University of Delaware. Christina C. Taylor is a Science Scholar in the senior author's laboratory.|