However, the high prices, especially in the soybean market, are expected to continue well into 2022 due to record-low ending inventories and international demand.
In either case, many have been forced to explore various feed products to mitigate the high and volatile protein prices. Many of these products are corn co-products. Although some of the products’ names are similar, the prices, nutrients and value of the products vary drastically. The co-products are developed from two corn milling processes – dry and wet milling.
Wet milling
The main purpose of wet milling is to separate the starch from the kernel. Many of the end products of wet milling are for human consumption. After several separations and centrifuging cycles, the starch of the corn can be isolated and converted into products such as high-fructose corn syrup, other corn syrups or pure dextrose.
Another fraction from the separated products is the corn germ. Corn oil can be extracted from the corn germ. Corn gluten meal, a large protein fraction of the corn, is also separated. The final fractions are the bran and steep liquor. The steep liquor is the liquid separated after the steeping process. Together, the bran, steep liquor and any distillers solubles make what we call corn gluten feed (CGF). Some or all the components of CGF can be dried. The dry CGF is often pelleted to increase the bulk density and handling capabilities. For the dairy industry, CGF and corn gluten meal are predominant products.
Corn gluten feed
CGF is an excellent feed for lactating dairy cows. It has a good combination of crude protein (CP) and digestible fiber (Table 1).
In this way, it can be used to replace some of the degradable protein sources that may be coming from soy, canola or alfalfa. The digestible fiber is also valuable as it can provide a dense form of energy that would normally have to come from corn grain. CGF can also replace some forage and the bulk and indigestible fiber portions that come with forages. In some research trials, CGF was fed up to 60% of the ration dry matter (DM) without impacting intake or performance. Typically, it is fed at 5% to 15% of diet DM.
Corn gluten meal
Although similar in name and production process, corn gluten meal is a very different product than CGF. Corn gluten meal has three times the amount of CP as CGF and is generally around three times the prices, as well. Around 60% of the protein in corn gluten meal is rumen-undegradable (RUP). Generally, this is desirable as RUP delivers amino acids to the intestine where the cow can utilize them. However, because corn is naturally deficient in lysine, the amino acid profile of corn gluten meal is not nearly as valuable to the cow as those we find in soy products. Because of this fact, treated soy products, blood meals and protected amino acids can deliver more essential nutrients per dollar.
Dry milling and distillers grains
The dry milling process is more straightforward than wet milling because there are only two products created – ethanol and distillers grains with solubles. In this process, corn is ground, fermented with yeast, and the starch is converted into ethanol.
Because of the huge growth in ethanol production over the last decades, so has the production and use of distillers grains products grown. Distillers nutrient composition varies dramatically depending on the ethanol plant. Generally, CP is around 30% and 34% neutral detergent fiber (NDF). However, the fat level, around 13%, is the main concern when feeding distillers to lactating dairy cows. The unsaturated nature and availability of the fat in distillers can hinder milkfat production. As milkfat production is not a concern in non-lactating animals, distillers are normally a good-value feedstuff to provide protein and energy to growing heifers.
Keep in mind: New production processes and products continue to enter the market. Products like high-protein distillers grains are becoming more available, but little research is available to understand the protein degradability and nutrient content.
The only thing certain about the upcoming year is uncertainty and likely volatility. As we move ahead, it is good to understand the different products in the market and their relative value. When prices are moving, we need to have the knowledge and confidence to buy the right products at the right price.
