determination of nutritional value in three forage species in three phonological stages in sabalan rangelands, ardebil, iran

in order to estimate the nutrient value of three dominant range species; festucaovina, trifolium montanum and alopecurus textilis via proximate analyses and gas productiontechnique, samples were collected in three stages during grazing period from 26th may to 1thseptember in six areas of sabalan mountain in north west of iran. results showed thattrifolium montanum as a legume had higher values for crude protein (cp), total ash,organic matter digestibility (omd), metabolizable energy (me) and gas production at 24hours and showed lower values for adf (acid detergent fiber) and ndf (neutral detergentfiber) as compared to two other species that were considered as gramineae. variation ofquality traits in trifolium montanum was lower than two other species. the obtained values ofcp, ndf, adf, ash, ee, omd, gas production and dry matter (dm) for trifoliummontanum were 18.65%, 41.83%, 26.97%, 8.95%, 0.26%, 64.50% g/kg and 50.96 ml/200mg,respectively. for festuca ovina, they were 9.37%, 68.63%, 36.87%, 6.77%, 0.58%, 53.82%and 40.04 ml/200mg dm and for alopecurus textilis, they obtained 5.01%, 73.03%, 42.18%,5.97%, 0.56%, 55.63 % and 35.46 ml/200mg dm, respectively. the values of me predictionthat were calculated via menke equation for trifolium montanum, festuca ovina andalopecurus textilis were 2.31, 1.93 and 1.75 mcal/kg dm, respectively. the mean level ofpredicted cp, me and omd for plants, especially in grasses (festuca ovina and alopecurustextilis) throughout the year, second and third stages of sampling (mid and late summer) andcomparing the nutrient requirements of moghanian sheep (native breed in ardabil province)with these data show that only at early stage of sampling (late spring and early summer), onecan supply sufficient nutrient for domestics whereas the ewes are pregnant at mid and end ofsummer and these nutrients are insufficient for them therefore, we have recommended the useof supplementary feeding in diets of grazing ewes for ideal productivity performance.