Grazing Behaviour and Plants Preference for Different Ages of Zandi Ewes in Steppe Rangelands of Qom (Iran)

Herbivores select diets from an array of plant species that differ in physical and chemical characteristics. Optimal intake of nutrients by grazing animals, however, could be more easily achieved if we were able to understand and control their dietary habits and preferences. Information on food habits of endemic sheeps in Iran is generally scarce. So one mixed flocks of sheep and goats were used in the study. The feeding behaviour of three Zandi ewes (1, 3 and 5 years old) in free grazing system was evaluated considering the plant palatability and preference value based on Close observation method (recording films by video cameras) in each month of grazing season. Then diet composition and preference index for each plant species calculated. Also Grazable Plant samples were dried and milled and analyzed by AOAC methods for qualitative factors such as: ADF%, CP%, ME, DDM%, etc. there were significant differences (p¿0.01) between different species in Nutritive value. Also, Interaction effects of species and sheep age on preference index were significant. But there were no correlation between diet composition/ preference index and forage quality. The plant preference index changed during different months too. Quite often, plants that constitute medium or small proportion of the rangeland made a large part of the grazing animal's diet. Animal experience, Month of grazing, taste, smell and plant cover were the most effective factors on sheep preference. Zandi sheep could be classified as Intermediate feeders in this rangeland.