Handling Steamed Corn Flakes
Report and comments by: James I. Sprague, Livestock Nutritionist
The June 2002 issue of the Journal of Animal Science included a invited
review paper by Richard Zinn, Fred Owens and R. A. Ware. They discussed
the importance in the flaking process of corn on starch digestibility
and feed efficiency. They included in the paper a discussion of the
effect of leaving the flakes in the pile or bin and letting the starch
change from the continued heating and moisturizing in the pile. This
process is referred to as retrogradation.
Retrogradation
They define retrogradation: "Retrogradation refers to the re-association
of dispersed starch molecules." They explain that retrogradation
causes a "glue like hardening of affected segments of starch,
this decreases porosity of the internal starch matrix and limits rehydration
and enzyme penetration." (I presume this means in the rumen and
then down the small intestine and colon.) They report from lab tests,
starch availability was 40 percent lower for the stored flakes than
fresh flakes from the roller mill. Yet, with in vitro test,s the digestion
was not different (in vitro is another lab test). I do not know of
any feeding test of stored flakes versus fresh flakes. These results
may be available.
Feeding Fresh Flakes
It appears from their paper, there is some risk of holding flakes
in storage. So at this time we recommend that flakes be fed a soon
as practical after flaking. Holding flakes overnight is probably not
recommended at this time. Yet in many cases holding flakes is needed
to "get the cattle fed." The retrograde process possibly
is a slow process and a short time of holding flakes in a storage
areas may be acceptable.
Drying Flakes
The authors state: "Allowing steam-flaked corn to dry is not
synonymous with retrogradation." They report similar tests of
starch gelatinization between fresh and dried flakes. They also report,
"no differences were detected between fresh and air-dry steam
flaked corn in ruminal or total tract starch digestion." It is
interesting to remember that the original flaked research and demonstrations
at Colorado State University by Matsushima and others were accomplished
with dried flakes. Also dried flakes are routinely used for dairy
cow feeding for material handling and mold prevention reasons.
Therefore, drying corn flakes for material handling reasons is recommended.
Keeping Flakes Intact
Most feedlots try to keep the flakes intact. The reason is prevention
of fines. I do not know of research to absolutely determine if breaking
up flakes really effects the starch utilization of the grain. My opinion
is that making good flakes is a priority and good bunk management
of getting the cattle to clean up the last feeding will overcome any
problem of fines created by rough handling of flakes.
Questions or comments on this or any article by Dr. Jim Sprague can
be addressed to him at 625 Grandview, Newton, Kansas, 67114. Or call
him at (316) 283-8692.
Beef Producers Support Checkoff
According to the results of an independent survey released during
the Cattle Industry Summer Conference, 66 percent of producers approve
of the beef checkoff. Additionally, nearly 70 percent believe the
checkoff helps producers compete with the aggressive promotion programs
of poultry and pork, 71 percent believe that the beef checkoff program
has value, even when the market is down and three out of five producers
believe that if there were no beef checkoff program, no one else would
pay for beef promotion. ©
