f fermented forages:
Phase I
As the forage is harvested,
aerobic organisms predominate
on the forage surface. During the
initial ensiling process, the freshly
cut plant material, and, more
importantly, the aerobic bacteria,
continue to respire in the silo
structure. The oxygen utilized
in the respiration processes is
contained within and between
the forage particles at the time
of ensiling.
This phase is undesirable because
the aerobic bacteria consume
soluble carbohydrates that might
otherwise be available for the
benefi cial lactic acid bacteria or
the animal consuming the forage.
Although this phase reduces
the oxygen to create the desired
anaerobic conditions, the
respiration process produces
water and heat in the silage mass.
Excessive heat buildup resulting
from an extended Phase I period
can greatly reduce the digestibility
of nutrients such as proteins.
Another important chemical
change that occurs during this
early phase is the breakdown of
plant proteins. Proteins fi rst are
reduced to amino acids and then
to ammonia and amines. Up to
50 percent of the total plant
protein may be broken down
during this process. The extent of
protein breakdown (proteolysis)
is dependent on the rate of pH
decline in the silage. The acid
environment of the silage eventually
reduces the activity of the
enzymes that break down proteins.
Phase I ends once the oxygen
has been eliminated from the
silage mass. Under ideal crop
and storage conditions, this phase
will last only a few hours. With
improper management, this phase
could continue for several weeks.
The primary objective at ensiling
time is to manage the crop so air
infi ltration is minimized, thereb
f fermented forages:Phase IAs the forage is harvested,aerobic organisms predominateon the forage surface. During theinitial ensiling process, the freshlycut plant material, and, moreimportantly, the aerobic bacteria,continue to respire in the silostructure. The oxygen utilizedin the respiration processes iscontained within and betweenthe forage particles at the timeof ensiling.This phase is undesirable becausethe aerobic bacteria consumesoluble carbohydrates that mightotherwise be available for thebenefi cial lactic acid bacteria orthe animal consuming the forage.Although this phase reducesthe oxygen to create the desiredanaerobic conditions, therespiration process produceswater and heat in the silage mass.Excessive heat buildup resultingfrom an extended Phase I periodcan greatly reduce the digestibilityof nutrients such as proteins.Another important chemicalchange that occurs during thisearly phase is the breakdown ofplant proteins. Proteins fi rst arereduced to amino acids and thento ammonia and amines. Up to50 percent of the total plantprotein may be broken downduring this process. The extent ofprotein breakdown (proteolysis)is dependent on the rate of pHdecline in the silage. The acidenvironment of the silage eventuallyreduces the activity of theenzymes that break down proteins.Phase I ends once the oxygenhas been eliminated from thesilage mass. Under ideal cropand storage conditions, this phaseจะสุดท้ายเพียงไม่กี่ชั่วโมง มีการจัดการไม่เหมาะสม ขั้นตอนนี้สามารถดำเนินการต่อไปหลายสัปดาห์วัตถุประสงค์หลักที่ ensilingเวลาจะจัดการพืชผลดังนั้น เครื่องปรับอากาศinfi ltration ถูกย่อเล็กสุด thereb
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