The objective of this study was to investigate the effect of three semi-arid climates (cold, moderate and warm with the annual temperature range of −20 to 22, −2 to 24, and 2 to 35°C respectively) on crude protein (CP), starch (ST), soluble sugar (SC), bulk density, acid detergent fiber (ADF) and organic matter digestibility (OMD) of sixteen barley grain varieties obtained in year 2008 (10 samples per each variety). Samples were ground (1 mm) and the chemical compositions were determined as proposed by standard methods. Three ruminally fistulated sheep (49.5 ± 2.5 kg) were used as rumen liquor donor for gas production technique. The animals were fed 0.8 kg DM alfalfa hay and 0.5 kg DM concentrate (165 g CP/kg of DM). Rumen fluid was collected before the morning feeding and strained through 4 layers of cheesecloth into a CO2-filled flask. In vitro incubation of the samples was done using a manual pressure transducer technique. Approximately 200 mg of each sample was weighed into 120 ml serum bottles (n= 4). The bottles were pre-warmed at 39°C before the injection of 30 ml rumen fluid-buffer mixture into each bottle followed by incubation in a water bath at 39°C. Gas produced were recorded at 72 h after the incubation. These data were used to estimate the organic matter digestibility of the samples. Starch content of cold region varieties was significantly (P < 0.05) higher (65.65%) than those of warm region (55.29). The samples obtained from the warm climate had the highest amount of crude protein (11.68%), while it was the lowest (10.57%) in the cold region samples. Soluble sugar contents of moderate climate varieties was more than the cold and warm climate samples and the differences were significant (P < 0.001). Varieties of the cold and warm climates had the highest (80.03%) and the lowest (78.03%) organic matter digestibility (P < 0.05), respectively

Keywords