Classification of forage quality index in highland rangelands of Taleghan

In order to maintain the nutritional status of livestock and achieve optimum performance of livestock on rangeland، range forage must be able to provide the minimum requirement of grazing animal at various phenological stages. However، to be aware and getting informed of whether the rangeland forage does have such a potential or not، it is necessary to provide a framework on the basis of scientific principles to classify the forage quality index. Moreover، this framework must be simple in terms of functionality and applicability to be used by the specialists. Until now، such a framework has not been provided for range forage. Therefore، in the current paper، not only was the information of forage quality index of species in rangeland types of Taleghan provided، but also the desirable forage quality of species was classified. The species having more than 7 % crude protein (CP) were very desirable; the ones having less than 5 % crude protein were considered undesirable and if the crude protein of species were between 5 and 7 %، they would be desirable. The species having more than 60 % dry matter digestibility (DMD) were very desirable; the species having less than 40 % dry matter digestibility were undesirable and if the dry matter digestibility of species were between 40 and 60 %، they would be desirable. The species having more than 8 Mj/Kg DM metabolisable energy (ME) were very desirable; the species having less than 5 Mj/Kg DM metabolisable energy were undesirable and if the metabolisable energy of species were between 5 and 8 Mj/Kg DM، they would be considered desirable. The values of 7% crude protein (CP)، 50% dry matter digestibility (DMD) and 8 Mj/Kg metabolisable energy (ME) were considered as the critical levels for maintenance requirement of an animal unit (non-pregnant and dry sheep with a mean weight of 50 kg). The daily requirement (dry forage) of grazing animal unit equivalent (Fashandi breed sheep with the weight of 60. 7 Kg) in rangeland types varied between 1. 5 and 2. 4 Kg per day when the forage quality was desirable. This value was less than 1. 5 Kg when the forage quality was very desirable while it reached to 2. 4 Kg when the forage quality was undesirable. Daily requirement of animal unit equivalent in rangelands of Taleghan in phenological stages of vegetative stage، flowering and seeding stage were 1. 3، 1. 6 and 1. 9 Kg، respectively that the minimum and maximum values were recorded for vegetative and seeding stage، respectively. Results، discussion and the presented framework of classification in this paper are regarded as the fundamental information for management of animal and the rangeland in Taleghan and similar habitats in Iran، being able to provide a part of information for methods of determining the range condition، range trend and grazing capacity.