Investigation of grazing behaviour and diet selection by Zandi sheep (case study: desert rangelands of Houze Sultan, Qom)

Optimal intake of nutrients by grazing animals can be achieved if we were able to understanding and controlling their dietary habits and preference. Without understanding these behaviours, correct management of rangelands is not possible. Therefore, in desert rangelands in Qom province two fenced enclosures (1 ha. area) were constructed in which plants production and intake measured during grazing period. 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 camera) in each month of grazing season. Then diet composition and preference index for each plant species calculated and compared. Grazing cycle) distance and motivation speed and time spent for grazing, resting or walking) were assessed using a GPS mounted on the back of sheep. The results showed that during grazing season, Tamarix passerinoides And Alhagi camelorum- in first and second vegetation type - had the highest preference index, respectively. The highest diet composition was related to Halocnemum strobilaceum and Alhagi camelorum. Animal experience, plant’s flavor, plant cover and composition were the most effective factors on sheep preference. In Houze sultan, sheep showed browsing behaviour. There were significant differences in diet selection (p<0.01) among three ewe ages. Considering to plants phenology and soil moisture conditions, Presence period of Livestock in Houze sultan range was suitable but a rest- rotating grazing system can be suggested in period of flowering of Tamarix sp.