Part 1, Section 4: Corn
Corn
TYPES
Waxy corn
The carbohydrate or starch granules of regular dent corn consist of approximately 75 percent amylopectin and 25 percent amylose. Waxy corn has nearly 100 percent amylopectin.
Waxy corn initially was recognized as a valuable source of industrial starch. Results of the numerous feeding trials and evaluations of waxy corn that have been conducted over the last 20 years occasionally have shown a benefit in feeding waxy corn, but they have not been consistent. In general, changes in feed efficiency and production have been small and not significant, but usually in favor of the waxy corn. In one summary of nine beef feeding trials, the effect of waxy corn on animal gains ranged from a decrease of 3.3 percent to an increase of 10 percent. Averaged over all nine, waxy corn had a 2.2 percent advantage.
The Miner Institute in Chazy, New York, recently conducted a feeding trial to compare waxy and nonwaxy corn for dairy cows. It found no significant differences between the waxy and normal corn in milk production, butterfat, and dry matter intake. Similar results have been documented for the feeding value of waxy versus normal corn silage.
Yields of some waxy corns have been comparable to those of normal dent corn. Growers should have some estimate of the relative yield performance of specific waxy hybrids before growing any substantial acreage. Waxy corns must be grown in isolation from other corn types in order to maintain purity standards for industrial use. Keeping the harvested grain separated by 12 to 16 border rows from the rest of the field is considered adequate isolation; 5 percent contamination with regular corn pollen generally is considered the upper limit.