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Why inoculate high moisture corn? What kind of inoculant should be used for high moisture corn? What pH is desired to preserve high moisture corn? Will inoculation prevent HMC from heating during summer feedout? |
Inoculating High Moisture Corn by Patrick
Hoffman and Richard Muck High moisture corn (HMC) is harvested between 25 and 35% moisture content and stored in a silo where it is preserved through fermentation. The optimum harvest moisture for good fermentation of HMC is 28 to 32%. In general, high moisture corn ferments more slowly and less extensively than corn silage. Fall weather conditions, maturity of the grain, speed of harvest, type of storage, and ability of the storage structure to exclude oxygen all have an impact on high moisture corn fermentation. To insure proper fermentation growers may want to consider the use of an inoculant. Why inoculate high moisture corn? Growers should consider the use of inoculants with high moisture corn because it ferments more slowly and less extensively than corn silage. Any aid to hasten fermentation and use up available oxygen is beneficial in the ensiling process. High moisture corn inoculants can increase the speed of fermentation, reduce dry matter loss, and increase aerobic stability. Inoculated high moisture corn may also improve animal performance. What kind of inoculant should be used for high moisture corn? Chose an inoculant that has been specifically developed for ensiling high moisture corn. Bacterial species that improve fermentation of high moisture corn include Lactobacillus plantarum, Enteroccocus, Streptococcus faecium, and various Pediococcus species. These are similar to bacteria found in inoculants for other crops. However, specific strains of these bacteria may not grow well on all crops and across a wide range of moisture contents. So a corn silage inoculant may or may not work well under the drier conditions of high moisture corn. Some high moisture corn inoculants may contain Propionibacterium. These bacteria are included to produce propionic and acetic acids to inhibit the yeasts and molds that often cause heating in high moisture corn. To date, the results of research using Propionibacterium to aid fermentation and prevent mold damage has been variable. With all inoculants, it is important to follow the manufacturer’s application rates. Typical rates are between 100,000 and 500,000 colony forming units (cfu) per gram of high moisture corn. What pH is desired to preserve high moisture corn? In a proper fermentation process, the pH of high moisture corn should drop quickly to 4.0 to 4.3. If the final pH is greater than 4.5, the corn will be prone to heating and spoilage. Will inoculation prevent HMC from heating during summer feedout? Inoculation of high moisture corn in no way guarantees aerobic stability. High moisture corn commonly heats during feedout, especially during summer months. University of Wisconsin research has observed 5-6 lb/day/cow milk losses when aerobically unstable high moisture corn was fed to lactating cows. Aerobic instability of high moisture corn is a dynamic event involving oxygen exposure, yeast, mold, slow feedout rates, and temperature of the high moisture corn mass. Chronic aerobic instability of high moisture corn is usually a management system (slow filling) or storage (silos too large) problem and there are no easy solutions. Increasing corn removal rates is an effective method to reduce heating, but is seldom practical on a farm. Numerous producers utilize high moisture corn only during the cool months (October to May) and rely on dry grains during summer months to alleviate this problem. Treating high moisture corn with organic acids at ensiling is also a viable solution to control chronic aerobic instability. |
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