Objective: Investigate the effects of whole or rolled corn with 20 or 40% forage diets on yearling steers performance

Corn included in growing and finishing feedlot diets is typically processed by dry rolling, grinding, or steam flaking.  The topic of how much processing and when to process is still debated.  Forage level and moisture content of dietary ingredients, as well as other unknown factors may interact with the processing level and contribute to the variability in animal response.  Our objective was to evaluate effects on animal performance and carcass characteristics from feeding whole or rolled corn in finishing diets with either 20% or 40% of the diet dry matter inclusion from grass hay.

One hundred and eight black crossbred yearling steers (917 ± 2.49 pounds initial body weight) were used to evaluate feeding whole or dry-rolled corn in diets with either 20 or 40% of the diet dry matter included from grass hay.  Steers were randomly assigned to one of 12 pens (9 animals /pen) at the CREC.  Each pen was randomly assigned to one of 4 treatment diets: 1) 55% whole corn with 20% grass hay; 2) 55% dry-rolled corn with 20% grass hay; 3) 35% whole corn with 40% grass hay; 4)35% dry-rolled corn with 40% grass hay; (Table 1).

Implications:  There were no forage level by corn type interaction, indicating across each forage level (20% or 40%) when the same corn type (whole or rolled corn) was included in the diet it resulted in similar animal responses.  Feeding diets with 40% forage as hay did impact final animal weights having lighter final weights than 20% forage at the same harvest end point.  This was anticipated, due to lower energy value of the diet and was reflected by lower average daily gains with the 40% vs. 20% forage diets (Table 2). Thus the feed to gain ratio (pounds of feed required to gain a pound of body weight) was greater for the 40% vs. the 20% forage treatment. Whole or rolled corn resulted in similar weight, average daily gain and dry matter intakes.  However there was a tendency for rolled corn to be more efficient as indicated by the lower feed to gain ratio.

Chanda Engel
Livestock Research Specialist