The comparison of digestibility of wheat straw by rumen bacteria and rumen microorganisms of Holstein cow and Khuzestan water buffalo

The number and type of bacteria in the rumen of cattle and buffaloes in different regions and consequently the digestibility of nutrients in them are different. The aim of this study was to compare the digestibility of wheat straw by rumen microorganisms and rumen bacteria of Holstein cow and Khuzestan buffalo under similar feeding conditions. Digestibility of dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of wheat straw was measured by total rumen microorganisms and rumen bacteria of cow and buffalo by two-stage digestion method and specific bacteria culture. In vitro digestibility of DM of wheat straw by total rumen microorganisms of buffalo (62.75 %) were more than cow (59.07 %), also DM and NDF digestibility by the rumen bacteria of buffalo (37.90 and 30.98 %) was more than cow (33.66 and 27.05 %) (P<0.05). However, regarding to NDF and ADF digestibility by total rumen microorganisms and ADF digestibility by the rumen bacteria, digestibility of rumen buffalo was only numerically more than cow. Regardless of the microorganism type, DM and NDF digestibility by the rumen microorganisms of buffalo (50.32, 43.23 %) was higher than cow (46.36, 39.54 %) (P<0.05).The comparison of digestibility of DM, NDF and ADF of wheat straw by the rumen bacteria in specific rumen bacteria culture showed that digestibility for buffalo in 48 and 96 hours was significantly higher than cow (P<0.05). Regardless of the time, digestibility of DM, NDF and ADF in specific rumen bacteria culture of buffalo was more than cow (P<0.05). Regardless of the animal type, by increasing of incubation time (from12 to 96 hours), digestibility of DM, NDF and ADF was increased linearly (P<0.05). Total bacteria concentrations of Khuzestan buffalo (1.9×105 cells/ml) was more than Holstein cow (0.92×105 cells/ml) (P<0.05). According to our results, under similar feeding conditions, digestibility of wheat straw was superior by Khuzestan buffalo than Holstein cow.