NCI Future of Feeding Webinar Series | Featuring Dr. Glenn C. Duff

Dr. Glenn C. Duff, Professor from New Mexico State University

Each month, NCI holds a new update in the Future of Feeding webinar series, which focuses on using innovation in the processing of animal food, the equipment being used, as well as using grains from our region for co-products. This month, we featured speaker Dr. Glenn C. Duff, Professor from New Mexico State University. He discussed “Steam Flaking for Cattle & its Impact on Performance and Carcass Characteristics” during the webinar.

Duff began his discussion by discussing traditional animal feedstock characteristics. They’re typically corn-based, and this base ingredient provides sufficient nutrients to the livestock while being easy to produce. However, wheat, sorghum grain, and barley are also used to produce feedstock. This feedstock can either be processed using steam flaking, dry rolling, or high moisture harvesting methods. However, steam flaking has become the most common method due to its ability to improve the feedstock’s starch availability, nutrient utilization, and its overall feeding value (as proven in a 2002 research study that Duff cited). He also cited a 1966 study in which it was proven that steam processing and flaking milo feed significantly increases digestibility of the total digestible ingredients in a high-grain diet.

Different feedstock products made from steam flaked grains.

He also pointed out that the bulk density of the product influences the amount of grain added to the feed during the flaking process. It’s common for some feedlots to flake to 26-28 lb/bu, and some use even more. The net energy available in the feed is affected by the processing method used, with this flaking process offering the highest potential of the three. This, once again, feeds into why it has become such a popular way of feedstock manufacturing lately.

The starches mentioned earlier exist as small granules in the endosperm region of the corn kernel. This highly-crystalized region is surrounded by a less-dense amorphous region, and the granules are embedded in a protein matrix. If there exists sufficient energy to break the bonds in the crystalline region, the starch begins to gelatinate. This energy can be introduced by either mechanical, thermal, or chemical means, but, regardless of the type chosen, water is needed to kickstart the process. These gelatinized grains are digested to a greater extent in the rumen and total tract region of the animal, and it’s also important to note that the benefits of these grains is inversely related to the digestibility of the unprocessed grain.

Corn steam flaking machine diagram & photo.

The process for steam flaking corn is relatively simple, helping spur its rise to one of the top feed manufacturing processes. First, the corn is loaded into a steam chest. From there, it’s steamed for around 35 minutes (this is variable depending on the size of the chest) and, using ram pressure to regulate the roll gap, the corn is rolled to the approximate desired flake density. Duff noted that some mill operators choose to reduce the flow of steam to the lowest section of the steam chest, though it’s important for the rolls to be hot and kernels to not cool before being flaked; otherwise, the quality of the product will be diminished. Finally, once the corn is flaked to the desired measure, it’s either air lifted or dragged into bins for shipment.

Retrogradation is a process that refers to the re-association of dispersed grain molecules. This process causes a glue-like hardening of the affected segments of starch, which decreases the porosity of the internal starch matrix while also limiting rehydration and enzyme penetration. Related to this process are surfactants, which are typically altered in order to facilitate moisture absorption in the kernel. Doing this not only decreases the time needed for this absorption to occur, but also allows for more moisture to migrate internally rather than sticking to the surface of the kernel while also decreasing the need for longer periods of steam-conditioning. If this moisture on the outside of the kernel wasn’t forced inward of the kernel, it would quickly be lost during the flaking process.

According to a study from 2002 (different from the one cited earlier), the value of corn is increased dramatically as a result of the steam flaking process. That study found an 18% increase in value when processed this way, which exceeds what was even predicted in the tabular values analyzed prior to the study. However, there’s also a caveat with the feedstock produced using this method: according to this study, feed produced using this method may increase the variability of weight gain amongst the livestock consuming it and also predispose them to acidosis and bloat. As such, it’s recommended that the steam flaking process be optimized on the basis of fecal starch analysis to help alleviate this problem.

That same year – 2002 – Duff and a few of his colleagues conducted their own work in the form of three studies that sought to determine the effects of differing proportions of steam flaked corn and steam flaked sorghum in the finishing diet of livestock. It also sought to explore the link between switching grain sources in the finishing period and the performance/carcass characteristics of finishing beef steers. The results of this study concluded that there was no real benefit from mixing these two steam flaked grains in finishing diets, and that switching grain sources during the finishing period may adversely affect performance.

The final study Duff discussed was conducted in 2020, and sought to explore the link between the effects of dry rolled corn vs. steam flaked corn and the carbon footprint of cattle feeding. It found that, although steam flaked corn required more fossil fuel than dry rolled corn, feeding steam flaked corn improved corn utilization. Hence, the carbon footprint in total was reduced by 9-13% per individual steer.

The Northern Crops Institute greatly appreciates Dr. Glenn C. Duff’s involvement and input in our webinar. At NCI, we continue to work towards fulfilling our mission to support regional agriculture and value-added processing by conducting educational and technical programs that expand and maintain domestic and international markets for northern grown crops. All of this wouldn’t be possible without the innovative ideas of guest speakers like Dr. Duff.    

For more information about future webinars offered at NCI, click here.

To watch the recording, click the video below.