Processing corn or increasing the amount of roughages in feedlot rations does little to enhance steer performance, say Ohio State University researchers.

During a 186-day feeding trial, 108 crossbred steer calves were fed one of four dietary treatments: 1) 85% concentrate diet fed for 186 days, 2) 100% concentrate diet fed for 186 days, 3) 85% concentrate diet fed for 84 days followed by a 100% concentrate diet fed for the remaining 102 days, or 4) 100% concentrate diet fed for 84 days followed by an 85% concentrate diet fed for the remaining 102 days. Corn silage was added as roughage.

During the first 84 days, the level of dietary concentrate did not affect average daily gain. Steers switched to the 85% concentrate diet for the last 102 days had higher dry matter intake than those fed the 100% concentrate diet. However, they did not exhibit an increase in average daily gain.

Finishing phase feed efficiency was highest for steers continually fed 100% concentrate, lowest for steers continually fed 85% concentrate and intermediate for steers whose concentrate level was switched during the trial. Carcass characteristics were not affected by concentrate level.

In a second trial, 108 crossbred steer calves were fed for 158 days to determine if feedlot performance could be enhanced by manipulating roughage level and grain processing.

Staged increases in concentrate level (70 to 85 to 100%) were compared to staged decreases in concentrate level (100 to 85 to 70%). Diet concentrate levels were changed after 56 and 112 days on feed. Feeding whole vs. rolled high-moisture corn was also compared. Corn silage was added as roughage.

During the first 56 days, steers fed 70% concentrate diets grew 11% faster and consumed 19% more feed than those fed 100% concentrate diets. Steers fed rolled corn gained 8% faster and were 7% more efficient than those fed whole corn. However, during the last period (Days 113 to 158) average daily gain was not affected by concentrate level or corn processing.

Researchers concluded that although increasing roughage during the feeding period increased feed intake in both trials, steer performance was not enhanced; processing high-moisture corn did not affect feedlot performance.

For more information contact Steven Loerch, Ohio State University, at 330/263-3900.

Processing wheat with micronization makes it more appealing for feedlot rations, Canadian researchers have found.

Micronization is a form of infrared heat treatment in which internal temperatures of feed products are raised to over 90 degrees C for 30 to 120 seconds.

Three wheat varieties (Sceptre, Laura and Kansas) were micronized and rumen disappearance rates were compared to those of untreated samples. Micronization reduced disappearance rates to 65-73% compared to 85-90% for unmicronized samples.

Researchers concluded micronization lowers protein degradability because the endosperm is largely undamaged. Whereas fine-grinding disrupts the wheat structure, allowing immediate microbial access to the starch.

For more information contact Tim McAllister, Lethbridge Agriculture and AgriFood Canada research center, at 403-327-4561.