In vitro fermentation of conventional diets commonly fed to dairy cows in Central Myanmar

This study consisted of two experiments conducted to evaluate the effective net gas, fermentation kinetics (experiment 1), methane gas concentration, partitioning factor (PF) for microbial protein synthesis and in vitro dry matter digestibility (IVDMD) (experiment 2) of conventional diets commonly fed to dairy cows in Central Myanmar. The conventional diets from four areas [diet from Sin Tel area (Diet-ST), diet from Myay Ngu area (Diet-MN), diet from Ta Pel area (Diet-TP) and diet from Amarapura area (Diet-AM)] were used as experimental diets in this study. In most of conventional diets, rice straw, sorghum stover and natural grass were used as roughage source and cotton seed cake and broken rice were used as concentrate. However in some diets, sesame residue and butter bean residue were used as roughage source instead of sorghum stover and natural grass. The roughage to concentrate ratio and crude protein (CP) content of conventional diets ranged from 53:47 to 72:28 and 11.46 to 17.96%, respectively. In experiment 1, the effective net gas volume of Diet-TP was lower (p<0.05) than Diet-ST and Diet-AM and generally, the fermentation kinetics (a, b, c and a+b) of Diet-TP were also lower than those of other diets. In the experiment 2, the lower value (p<0.05) of short chain fatty acid (SCFA) was found in Diet-MN and Diet-TP while the higher values (p<0.05) of metabolizable energy (ME) and organic matter digestibility (OMD) were observed Diet-AM and Diet-TP. Although methane gas concentration of Diet-TP was higher (p<0.05) than those of other diets, the greater values of IVDMD and PF were observed in Diet-TP. According to these findings, it was perceived that all conventional diets have different nutritional qualities which are useful for production and health of dairy cows; however the Diet-TP possessed the highest nutritional qualities among the conventional diets.