Authors : M. Murillo Ortiz, O. Reyes Estrada, E. Herrera Torres, E. Gutierrez Ornelas and H. Gonzalez Garcia
Abstract: The objective of this study was to evaluate the annual and seasonal changes on in situ degradability of dry matter, crude protein and neutral detergent fiber in the diet of grazing steers. For the statistical analysis a fixed effects model was used. Significant effects of years were observed in soluble fractions a, degradable b, degradation rate c of the Dry Matter (DM) and Crude Protein (CP) (p<0.05). Also was observed effects between years in the Potential Degradability of Dry Matter (PDDM), Potential Degradability of the Crude Protein (PDCP) and Potential Degradability of the Neutral Detergent Fiber (PDNDF) as well as in the Effective Degradability of Dry Matter (EDDM), Effective Degradability of Crude Protein (EDCP) and Effective Degradability of Neutral Detergent Fiber (EDNDF) (p<0.05). The values of a, b, c of DM and CP as well as the PDDM, PDCP, EDDM and EDCP of the diet in summer and in fall were higher than those observed in winter and spring (p<0.05). Soluble fraction A and degradable B as well as values of c of the Neutral Detergent neutral (NDF) in summer and fall were equal but different from those observed in winter and spring (p<0.05) while the PDNDF and EDNDF were different between seasons (p<0.05). We conclude that annual and seasonal weather changes affected in situ degradability of DM, NDF and CP in the diet selected by grazing steers.
M. Murillo Ortiz, O. Reyes Estrada, E. Herrera Torres, E. Gutierrez Ornelas and H. Gonzalez Garcia, 2010. Annual and Seasonal Changes in Ruminal Degradability of Diets by Grazing Steers in Native Range. Agricultural Journal, 5: 259-263.