MOLDS, MYCOTOXINS, F MOLDS, MYCOTOXINS, FUNGI UNGI UNGI

MOLDS, MYCOTOXINS, FUNGI
FUNGI
JOANNE ARMSTRONG AND CURT BOSSUYT
Molds, mycotoxins, fungi...; we hear these words floating around, but
do we really know what they mean or more importantly how they
impact our cows. Let’s dive into the world of molds and mycotoxins
and see if we can see how they will impact our herds.
First of all let’s start by defining what fungi, molds and mycotoxin are.
Fungi are the taxonomic kingdom including yeast, molds and smuts.
Mycotoxins are the substances produced by fungi (mold) under a
certain condition. Over 400 mycotoxins have been identified, of those
only several have been identified to have a biological or health impact.
Some of the more common mycotoxins include: Zearalenone,
Vomitoxin, Fumonisin, and Aflatoxin. Mycotoxins can be found on
both grain and forages. Molds grow under different environmental
conditions. For example some molds thrive in high humidity with hot
days and cool nights, where as others thrive in low pH, low oxygen
environments. The growth of these mold can occur in the field or
during storage. Table 1 outlines the mold type and the associated
mycotoxin produced as well as the mode of attack; field, storage or
both.
The safest way to feed mycotoxins is to not feed them at all. If you
have to feed the contaminated feed, feed to those animals that are less
sensitive to the affects of these toxins. Another practice for minimizing
the mycotoxins being fed is to dilute the affected feedstuff with
“clean” feeds .
Table 1.Toxin Producing Molds
The use of mycotoxin binders is another method. Mycotoxin binders aid
by isolating the mycotoxin(s) and prevent toxicity in the gastrointestinal
tract by preventing absorption across the gut wall. Binders may help in
some situations but may not be 100% effective, depending on the type
of mycotoxin and the other challenges present.
Some signs of mycotoxin in dairy cattle include:
•
rumen disorders and reduced microbial digestion
•
loose manure
•
reduced dry matter intake
•
decline in fertility
• weight loss
à Milk production and milk components may be reduced in some cases
It is difficult to diagnose the negative health effects of moldy feed
because mycotoxins residues are not easily detected in the cow. The
symptoms are often nonspecific and may be the result of a series of
events or diseases.
There are some ways to help reduce molds from occurring in your
forages or grains:
• Optimize soil fertility - producing a healthy plant will help
lower mold activity
• Crop rotation
• Disease resistant varieties of seed
• Timely harvest - proper moisture and maturity
• Use of bacterial inoculants
• Proper feed-out of feedstuffs - keeping the face of the silage
pile clean
• Minimize crop residue
Of the 400 mycotoxins identified, only several have a negative impact on
cow health. Identifying these mycotoxins and working with your
Landmark Feeds Representative to devise a feeding strategy will help to
minimize the impact on animal health and performance
Source:http://www.plantpath.wisc.edu/PDDCEducation/ScoutSchool/Gen
eral/Slide56.htm