Nutrient composition | % of dry matter |
Crude protein (CP) | 45 to 55 |
Neutral detergent fiber (NDF) | 24 |
Starch | 8 |
Ether extract (Fat) | 11 |
“We can’t just assume that it will feed like soybean meal just because they have a similar percentage of protein,” explained Billy Brown, assistant professor at Kansas State University. “The product we tested was a bit different from typical high-protein dried distillers grains (DDGs), but treads along the same lines with higher crude protein (CP) and less fiber.”
Protomax is a proprietary coproduct produced following the fractionation of the corn kernel before it goes into the ethanol process. This removes the bran, allowing more starch to be extracted for the ethanol production before yeast bodies are added back in the coproduct.
The coproduct was tested as a soybean meal substitute for post-weaned calves, 8 to 12 weeks of age. The results of this project were recently discussed on the “Dairy Science Digest” podcast.
Designing a diet
The control diet used soybean meal as the primary source of protein. “Soybean meal is the gold standard for what we would include in a calf starter grain,” he explained. The intermediate calf starter was 50:50 soybean to HPCC and the third ration was 100% HPCC. All grain mixes were 24% crude protein.
The amino acid (AA) concentration between soybeans and corn differs vastly. Corn coproducts are known to be low in lysine, while soy products are deficient in methionine, limiting amino acids (AA) for ruminants. To ensure the research was capturing the total CP difference, not amino acid differences, the HPCC diets included rumen-protected AA, a costly additive. Even after the addition, the high-protein corn coproduct diet remained a few cents less per calf per day. “We always have to make cost comparisons to remain competitive on a dairy,” Brown continued.
Calf performance was monitored during the postweaning phase. While it is common for calves of this stage to have up to 5% of their daily ration in hay, no hay was fed for this project to focus the results on the grain difference. Grain was offered at free choice.
Calf performance
Average daily gain (ADG) at this stage is directly correlated to first-lactation milk performance. Ensuring a lean structural gain is important for developing dairy replacement heifers. Raising the inclusion rate of the HPCC in the starter grain linearly boosted body weight.
Calves consuming diets with the HPCC tended to have greater digestibility in both dry matter and protein, which was a surprise. Corn protein is notoriously challenging to digest due to the complex zein protein network surrounding starch.
Zein proteins are why nutritionists recommend ensiling or grinding corn before adding it to rations. The improved digestion resulted in a tendency for them to have a slight increase in dry matter intake as the corn coproduct increased in their ration. Improved protein digestion in the HPCC diet suggests an improved ruminal environment.
More than just protein
While dairy farms have used by-products of the ethanol industry for years, few stop to think about the process. To create ethanol from corn, small single-celled yeast organisms are added to a large vat and heated to create ideal conditions for anaerobic fermentation. During the fermentation process, the starch is converted to ethanol, and the solid fraction is then centrifuged off and dried. Throughout this process, the yeast bodies remain and can be separated off then concentrated for feed purposes.
Research results are mixed on feeding yeast and yeast products to ruminants. “I think that is the next question to answer,” said Brown. “The HPCC contains a high concentration of highly digestible yeast bodies, and future research could help us know if that is the cause for improved grain digestibility.” Perhaps when conditions are right, these dietary yeast bodies could have a positive impact on production.
To ensure success and profit, assessing breakeven on the operation’s rations requires a sharp pencil. To learn more about how to integrate HPCC into your farm, listen in to the monthly podcast, “Dairy Science Digest” on your favorite podcast platform, or access the peer-reviewed open access Journal of Dairy Science article found at: www.journalofdairyscience.org.
