Corn grain has traditionally been the cheapest source of starch. However, in light of high corn prices, it is wise to evaluate other starch sources. Bill Weiss, professor and extension dairy specialist at The Ohio State University, offers a look at how to reduce corn and still achieve a diet with 25 percent starch:
• Wheat and barley contain 65 to 75 percent starch. This starch is usually more digestible than the starch from corn grain. “Usually, but not always, they are more expensive sources of starch and energy than corn,” Weiss says. However, because wheat and barley starch is more digestible than corn starch, you do not need to feed as much of it in the diet, which may result in some feed cost savings.
• Hominy contains about 50 to 55 percent starch and can be a major starch source if the price is competitive. However, hominy is higher in fat than corn grain, which limits its inclusion rates to no more than 20 percent of dietary dry matter.
• Corn silage, depending on hybrid and maturity, contains 20 to 40 percent starch. “To obtain a diet with 25 percent starch and using average corn silage, an average Holstein cow would need to be fed about 5 pounds more corn per day when fed a diet with 55 percent forage comprised of 70:30 alfalfa:corn silage than if she was fed a diet with 30:70 alfalfa:corn silage,” Weiss says.