EFFECTS OF BACTERIAL INOCULATION OF HIGH-MOISTURE EAR CORN ON ITS AEROBIC STABILITY, DIGESTION, AND UTILIZATION FOR GROWTH BY BEEF STEERS

High-moisture ear corn (HMEC) was treated with specific bacterial inoculants and evaluated for its aerobic stability and utilization for growth by beef steers. Immediately after harvest, HMEC (65% DM) was ensiled in tower silos after being either untreated (control) or treated with the following inoculants: 1) Ecosyl(R) (E); 2) Ecosyl plus Serratia rubidaea (E + SR); and 3) Ecosyl plus Streptococcus thermophilus (E + ST). A portion of HMEC was frozen immediately (-20-degrees-C) and subsequently treated with eight bacterial inoculants before ensiling in laboratory silos; the fermented material was then exposed to air for 7 d for assessment of aerobic deterioration. The eight inoculants included the three used in the tower silos and four additional ones: Streptococcus thermophilus, Bacillus subtilis (BS), Serratia rubidaea, and a mixture of Ecosyl + B. subtilis (E + BS). The growth trial was conducted for 112 d with 32 crossbred steers (average BW 296 kg). A digestion trial was conducted, according to a 4 x 4 Latin square design, using an additional four steers (average BW 367 kg). In both trials, steers were fed the same four diets containing inoculated (E, E + SR, and E + ST) or control HMEC. Upon exposure to air, Ecosyl-treated ensiled HMEC had the least increase in pH compared with other single inoculants; all inoculant treatments lessened (P < .05) the increase in sample temperature compared with control. During aerobic exposure, treatment of HMEC with BS seemed to reduce the disappearance of water-soluble caxbohydrates, whereas Ecosyl seemed to reduce lactic acid. Despite evidence of improved aerobic stability with Ecosyl and BS, inoculation of HMEC did not (P > .10) improve BW gain or feed efficiency; however, all inoculants reduced (P < .05) digestibility of ADF.