The Milk Producer - January 2012 - (Page 36)
RUMINATIONS
By Mario S. Mongeon and Tom Wright
Contamination to blame?
Mycotoxins produced by mold
in your grains or feed can
seriously impair your herd’s
milk production performance
I
f your cows have gone off feed and
milk production has dropped off,
mycotoxins in their ration could
be the culprit. An ear corn mold survey
last fall has shown elevated levels
of mycotoxins in some parts of Ontario.
Mycotoxin is a generic term for
toxic chemicals produced by mold
that colonize crops and stored feed.
One mold species may produce more
than one type of mycotoxin, and various
mold species may produce the
same mycotoxin. Examples of these
toxic chemicals are Aflatoxin, Zeralenone
and Vomitoxin (DON).
Molds can develop on various feed
types at various growth stages—before
harvest or during storage. When
weather conditions are right for their
growth, molds can grow on grain kernels
still attached to plants in the field
and produce mycotoxins. Corn and
wheat, for example, can show significant
mycotoxin levels at harvest.
Molds can also proliferate on stored
feed such as corn silage if oxygen
leaks into the silage mass.
Moldy feeds can typically cause
performance losses of
five to 10 per cent, even
if they don’t produce
mycotoxin.
Cattle
find
moldy feeds less palatable
and may reduce
their dry matter intake.
This lowered nutrient
intake
reduces
weight
gains or milk production.
When mycotoxins do
contaminate your feed,
they can cause problems
when cattle consume
them even at extremely
low levels. The toxins
can impair performance
and change normal metabolism,
mainly targeting an animal’s immune
function.
Young, pre-ruminant calves and
high-producing cows are most susceptible
to mycotoxins, and cows
already stressed by lameness, high
temperatures or improper rations are
also more at risk. The transition period
and at calving time are critical,
too.
Last fall’s ear corn mold survey,
conducted by the Ontario Ministry of
Agriculture, Food and Rural Affairs,
revealed some fields had elevated levels
of DON. Severity varied across
the province, but about 12 per cent of
fields sampled showed levels between
two and four parts per million (ppm).
A few fields even had levels in excess
of four ppm.
Other sources have reported even
greater concentrations in feed samples.
In one case, a silo of high moisture
corn has been analysed at 12
ppm of DON. Other data suggest
Zearalenone could be trending higher,
more so than DON.
Mycotoxin contamination can come
from purchased feed sources as well
as your fields or silos. Before buying a
load of corn distillers grains or similar
material, ask for a laboratory report
for mycotoxins.
The fermentation process does
Total Ration (on a dry matter basis)
Mycotoxin
DON/Vomitoxin
Zearalenone
T-2
HT-2
Various molds produce mycotoxins in feed.
36 | January 2012 | MilkPRODUCER
Concern level
(ppm)
0.56
0.56
0.25
0.25
Potentially harmful
to cattle (ppm)
2.5 to 6.0
3.9 to 7.0
0.7 to 1.5
1.5 to 3.0
Adapted from Penn State
Table of Contents for the Digital Edition of The Milk Producer - January 2012
The Milk Producer - January 2012
Contents
Editor’s Notes
DFO Chair’s Message
Dairy Update
DFC Promotion
Farm Finance
Research
Applied Science
Ruminations
Rearing Replacements
Markets
New’N’Noted
Back Forty
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