Investigation on forage quality of four range species of compositae family (A case study in rangelands of Baft in Kerman province)

    Determination of rangeland forage quality is an important factor in assessing the nutrition status of livestock dependent on rangeland, determining suitable grazing time, increasing livestock efficacy and less damaging to rangelands. This study was conducted to determine the nutritional value and digestibility of four dominant species of Compositae family in Baft rangelands located in Kerman province. The species including: Artemisia aucheri, Artemisia persica, Scorzonera tortusissimaand Cousina sicigera, which weresampled in phonological stages of vegetative growth, flowering and seeding. The results showed that the mean values of chemical composition of the mentioned species at different growth stages were 9.94, 8.9, 6.21 and 10.40% of crude protein (CP), 45.62, 45.77, 61.07 and 42.83% of NDF and 32.77, 33.05, 46.61 and 31.73% of ADF, respectively. By increasing age of all plant species, CP was decreased (P<0.01) but except for Scorzonera tortusissima, the values of NDF and ADF were increased in other species (P<0.01). The average digestibility of the mentioned species dry matter at vegetative, flowering and seeding stages were 57.41, 53.54, 45.34 and 39.67%, respectively. The average of metabolizable energy (ME) of the mentioned species at vegetative, flowering and seeding stages were estimated to be 2.24, 2.24, 1.86 and 2.26 Cal/g, respectively. The average concentrations of mineral elements such as calcium, sodium, potassium, magnesium, iron and manganese of these four rangeland species were more than the critical requirements of sheep and goat, while the concentrations of phosphorus, copper and zinc in these plants were less than the critical level for sheep and goat requirements. Generally, the four species studied in terms of CP and ME, especially in the early stages of growth, provide the needs of sheep and goats in the region.