Corn grain processing on the kinetics of in vitro dry matter degradation

Objectives.Determine the effect of processing corn grain on the kinetics of degradation and in vitro fermentation of dry matter. Materials and methods. There were five treatments, each one consisting of a mixture of two species, 70% Kikuyu grass (Pennisetum clandestinum) and 30% corn (Zea mays). The grain was subjected to various procedures: dry coarse corn (DCC), fine dry corn (FDC), reconstituted corn (RC), reconstituted and ensiled (REC) and silage with urea (REUC). In vitro gas technique was used to measure degradation parameters and gas production at different times up to 48 h. The Gompertz and the Ørskov and McDonald models were used to adjust gas production and degradation curves of DM, and they were evaluated with PROC NLIN from SAS. Results. The highest accumulated volumes were obtained from treatments with FDC and REUC with 524.03 and 552.5 ml, respectively and were different from the DCC treatment (p<0.05). The potential of degradation (A + B) in DCC showed the lowest value being different (p<0.05) with FDC, REC and REUC treatments. Conclusions. The type of processing of corn grain, as fine ground, reconstituted silage with and without urea, significantly improved the fermentation and degradation of DM parameters. The use of finely ground grain (2 mm) can be replaced by coarse reconstituted and silage, since it is cheaper than fine grinding.