The objective of the present study was to evaluate the ruminal dynamics of dairy steer fed diets containing whole corn grains, grains ground into grits or whole grain treated with urea. Thus, six rumen-fistulated animals were kept in confinement and fed diets with similar contents of energy and protein. The diet was formulated with 40:60 roughage:concentrate ratio in the dry matter using sorghum silage as roughage. The experiments followed a 3 × 3 latin square design, with three animals and three periods and they were repeated eith-er two or four times depending on the studied parameter, totaling six or 12 replicates per diet. Corn grain treatment did not affect the pH of the ruminal fluid neither the ruminal degradability of dry matter, acid detergent fiber and cellulose. All diets provided a concentration of amoniacal nitrogen suitable for ruminal microbial growth; however, for animals fed whole corn grain treated with urea, this concentration was significantly lower. Bacterial activity was lower in animals fed diets containing ground corn and they do not differ among animals fed whole corn grain or corn grains treated with urea.
bacterial activity; bovine; in situ degradability
