The Comparison of Corn and Soyhulls

Soybeans are a vital crop in agricultural production, primarily processed for their oil. This processing results in two significant by-products: soybean meal and soybean hulls. Soybean hulls, essentially the outer skin of the soybean, are produced during the oil extraction process. These hulls are relatively small and low in density, which leads to the common practice of pelleting them to enhance handling and bulk density. From a nutritional standpoint, both loose and pelleted soybean hulls offer comparable value. Typically, soybean hulls are priced competitively with corn, prompting a need for comparison on their nutritional merits.

Nutritional Comparison: Energy and Protein Content

When evaluating the nutritional aspects of corn and soybean hulls, the focus typically centers on two primary nutrients: energy and protein. Corn is known for its high energy content, boasting approximately 90% TDN (Total Digestible Nutrients), a measure of its energy value, along with a protein content ranging from 8% to 10%. In contrast, soybean hulls present a more complex picture regarding their energy content. Various publications have reported differing TDN values for soybean hulls, leading to some confusion in their nutritional assessment.

The following table summarizes the TDN values for soybean hulls from different sources:

Despite the variation in TDN values, there is consensus that soybean hulls contain about 12% crude protein. The discrepancies in energy content primarily arise from how soybean hulls are utilized in cattle diets. For instance, if cattle are fed a diet composed of 90% corn, they exhibit 10% to 20% faster gains compared to those receiving a diet consisting of 90% soybean hulls. However, when these ingredients comprise only a small portion of the diet, the performance of cattle fed soybean hulls can equal that of those fed corn.

Practical Feeding Trials: Corn vs. Soybean Hulls

To illustrate the practical implications of feeding corn versus soybean hulls, consider a scenario involving a group of cows that have recently begun calving. Initially, these cows consume around 25 pounds of hay daily. As they enter the calving period, it becomes necessary to supplement their hay intake. Let’s analyze the effects of adding 5 pounds of corn versus 5 pounds of soybean hulls to their diet.

When 5 pounds of corn are added to the diet, the cows' hay consumption drops to approximately 18 or 19 pounds per day. Despite the increase in energy intake, the overall total feed consumption is reduced to about 23 or 24 pounds. This reduction can negatively affect the digestibility of the hay, which is a critical factor for the nutritional health of the cows.

Conversely, when 5 pounds of soybean hulls are introduced into the diet, the cows adjust their intake to about 21 or 22 pounds of hay per day, while still consuming the 5 pounds of soybean hulls. This adjustment not only maintains a higher overall feed intake but may also enhance the digestibility of the hay. This demonstrates that, despite having a lower TDN per pound compared to corn, soybean hulls can be equally effective as a supplement for cattle on forage diets due to their positive effects on forage intake and digestibility.

Protein Content and Additional Benefits

Another advantage of soybean hulls over corn is their higher protein content. As previously mentioned, soybean hulls contain around 12% crude protein, while corn has only 8% to 10%. This increased protein level can be particularly beneficial in diets for lactating cows or growing cattle, where protein requirements are higher.

Moreover, soybean hulls offer additional benefits when incorporated into diets, such as:

• Enhanced forage intake
• Improved digestibility of feed
• Increased overall nutrient absorption
• Support for better weight gain in certain feeding scenarios

Conclusion

In summary, the comparison of corn and soybean hulls reveals that while corn may have higher energy content in isolation, soybean hulls provide significant advantages when included in forage-based diets. Their ability to enhance forage intake and digestibility, coupled with their higher protein content, makes soybean hulls a valuable supplement for cattle. Therefore, livestock producers should consider the overall benefits of soybean hulls in the context of their feeding strategies, especially when aiming for optimal animal performance during critical growth phases.

References:

• National Research Council (NRC) publications on beef and dairy cattle.
• Research studies on the nutritional evaluation of soybean hulls.
• Agricultural Extension Services on feed composition and livestock nutrition.