MORE ON STEAM FLAKED CORN - 10/96
At the 1996 Cornell Nutrition Conference a summary of corn processing was presented with the title:
STEAM FLAKING IMPROVES STARCH UTILIZATION AND MILK PRODUCTION PARAMETERS.
Dr. Theurer from Arizona State made the presentation and his concluding "bottom line" was:
"Increasing the proportion of starch digested in the rumen vs. intestines of dairy cows fed corn or sorghum grain improves performance by lactating dairy cows, particularly milk and milk protein yield without decreasing milk fat yield. This occurs with steam flaking of corn or sorghum grain which increases starch utilization and estimated amino acid uptake by the mammary gland."
The review was very similar to previous information in Pennfield TSR 9511PP and TSR 9605 PP. Special attention was given to improved nutrient use beyond the rumen. Steam flaking increased liver output of glucose 16% and mammary uptake of glucose 18%, and improved mammary uptake of amino acid nitrogen by 42%. This may help to explain why yields of milk and milk protein increase.
Dr. Chase at Cornell reviewed a new 1996 California study (JAS 74:310) in the latest Cornell Dairy Nutrition Notes. Steam Flaked corn resulted in 5.8 lbs. more milk, .3 lbs more milk protein, higher ruminal and total starch digestion, and more microbial protein produced per unit organic matter fermented. He concluded that as a conservative estimate, the energy value of properly steam flaked corn is 10 to 15% better than cracked or coarse ground corn based on these results.
Recently some have said that "fine" grinding corn is almost as good as steam flaking. Only one study at Arizona State University compared steam flaked corn to fine ground, coarse ground and steam rolled corn. This is one of the studies previously summarized in Pennfield TSR 9511PP. Properly steam flaked corn resulted in the highest level of milk production, fat corrected milk production, milkfat and protein yield compared to all other processes.
Cows fed fine ground corn produced 3.5 lbs less milk per cow per day and 4.2 lbs. less Fat Corrected Milk than properly steam flaked corn. Fine corn was second to properly steam flaked corn in milk production, ahead of coarse grinding or steam-rolling. However, fine grinding resulted in lower FCM than coarse or steam rolled corn due to lower fat % on fine ground corn. Statistically differences were not significant. Finely ground corn did result in significantly less intake - 8.6 lbs. less DM eaten daily when fed fine ground corn compared to the average intake on the other processed corn. This resulted in improved feed efficiency, but may be a concern regarding palatability.
Ruminal availability results reported in previous Technical Service reports would indicate that properly steam flaked corn is the most ruminally available source. Finely ground corn should be more available than coarsely ground or cracked corn. If a feed processor is unable to properly steam flake corn, fine grinding should be better than coarse grinding, dry-rolling, or cracking corn. However, corn that is finely ground may result in problems with dustiness, consistency and palatability. It is probably best used for TMR feeding. Often for stall barn feeding, extent of grinding is less to avoid palatability problems, thus resulting in more cracked or coarsely ground corn.
Field observations would indicate that a lot of ground corn on farms is not finely ground. One of the difficulties is characterizing what is "Fine" ground corn. It has been described as "chicken meal" or "so fine that you can't see any yellow". Research and field use in the future must characterize -by physical measurement- what cracked, coarse, and fine particle size means when discussing corn processing.
Steam flaking will maximize the value of corn grain for dairy cattle. For best results, use steam flaked corn in a properly balanced ration.
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