NATHAN SOARES DOS SANTOS

AUTHOR: NATHAN SOARES DOS SANTOS

TITLE: REHYDRATED CORN GRAIN SILAGE FOR BEEF CATTLE COFINED

ADVISOR:  Prof. Dr. Marcia Dias

DEFENSE DATE: 10/31/2018

ABSTRACT: The objective of this study was to evaluate the substitution of ground dry corn by rehydrated corn grain silage (SGMR, 0, 25, 50, 75 and 100%) in concentrate for confined beef cattle. Consumption (kg / day) and digestibility (%) were evaluated, considering the ruminal parameters (pH and ammoniacal nitrogen-N-NH3), blood (plasma glucose and urea), physiological (respiratory rate-RR and body temperature- BT) and ingestive behavior (time consumed in food intake, rumination and idleness; efficiency of intake and rumination of dry matter-DM and neutral detergent fiber corrected for ash and protein-NDF). Five crossbred steers were kept in individual stalls and arranged in 5x5 Latin square for 85 days. The data were evaluated by analysis of variance and with orthogonal contrast comparison. The pH and N-NH3 were analyzed in subdivided plot, considering the effect of the substitution in the plot and the moment of evaluation (0 and 4 hours after feeding) in the subplot. Consumption (DM, organic matter, crude protein-PB, ethereal extract-EE, NDF, carbohydrates-CHO, non-fibrous carbohydrates-CNF and total digestible nutrients- NDT) were not influenced by substitution of the dry corn milled by SGMR. There was a quadratic effect of the DMS and the BMD, with higher values in the substitution of 25 to 75%, whereas for the DFDN the highest values were 0 to 75% (P <0.05). For DCNF there was an increasing linear effect (P <0.05). The ruminal pH and N-NH3, glucose and plasma urea, RF, CT, times spent in food intake, rumination and leisure, and ingestion and ruminal efficiencies were not influenced (P> 0.05) by replacement of the dry corn milled by SGMR. The time of ruminal fluid collection influenced (P<0.05) the pH and the ruminal N-NH3. Although SGMR substitution does not affect consumption, ruminal and physiological parameters and ingestive behavior, it is recommended that 25 to 75% of rehydrated maize grain silage be replaced due to higher digestibility (DMS, BMD, DFDN and DCNF). The level of substitution will depend on the infrastructure and manpower available on the property and the climatic condition of the region.