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 Nguarea (Diet-MN), diet from Ta Pelarea (Diet-TP) and diet from Amarapuraarea (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.

This study aimed to compare nutritive values of local (Sorghum) and introduced (Mombasa) forages and their feed mixtures for ruminant feed in central dry zone of Myanmar. Sorghum based feed mixtures (FeedMix-1, 2 and 3) were the commonly used feed mixtures for cattle in dry zone of Myanmar and other feed mixtures (FeedMix-4, 5 and 6) were based on Mombasa. The lower CP and higher fibre contents (P<0.05) were observed in sorghum and its feed mixtures. The highest gas volumes (P<0.05) were observed in the FeedMix-4 and 6, and then the lowest gas volume (P<0.05) was observed in FeedMix-3. The gas production from quickly soluble fraction (a) of sorghum was significantly higher (P<0.05) than that of Mombasa, inversely the gas production from insoluble fraction (b) of sorghum was significantly lower (P<0.05) than that of Mombasa. Moreover, potential gas production (a+b), ME, OMD and SCFA of sorghum were also significantly lower (P<0.05) than those of Mombasa. The value of “a” was lowest (P<0.05) in FeedMix-1, whereas the highest value was found in FeedMix-6. The lowest values (P<0.05) of “b”, “a+b”, ME, OMD and SCFA were observed in FeedMix-3 and the highest values (P<0.05) of those parameters were found in FeedMix-4. Thus, the higher nutritive values observed in the introduced forage, Mombasa and its feed mixtures were indicating that Mombasa should be used instead of sorghum for the feed of cattle in dry zone of Myanmar.

The conventional diets have been fed to dairy cows since many years ago in Myanmar, however there is a little scientific information regarding the use of those diets as feed. Therefore, this study was conducted to evaluate the feeding values of conventional diets and their effects on the performances of dairy cows in Central Myanmar. Nine cross-bred Holstein Friesian cows (460±22kg) with the 12 th week of lactation were randomly allocated to one of three treatment groups with three replicates in a completely randomized design. The three treatments were Diet-ST (common diet from Sin Tel, Tatar U Township), Diet-MN (common diet from Myay Ngu, Tatar U Township) and Diet-AM (common diet from Amarapura Township). Cows were fed treatments for 60 days. The roughage to concentrate ratios ranged from 53:47 to 72:28 and the nutritive values were significantly different (p<0.05) each other. The highest nutrient intakes were observed in dairy cows fed on Diet-MN, however the nutrient digestibility were not different (p>0.05) except the CP and ether extract digestibility (CPD and EED). The nitrogen utilization was highest in dairy cows fed on Diet-ST and the lowest value was observed in the dairy cows fed on Diet-AM. Although the milk compositions were not different (p>0.05), the average milk yield of dairy cows offered the Diet-MN was significantly higher (p<0.05) than those of dairy cows fed on other diets. The highest total feed cost (p<0.05) was found in Diet-AM and the lowest value (p<0.05) was in Diet-MN. According to these findings, it was concluded that the highest feeding value was observed in Diet-MN and its effect on the performances of dairy cows was also greater than others. Moreover, it would be suggested that better bean residues and sesame residues could be used as fibre sources in the diets of dairy cows.