Determination of linear regression model to estimate the water requirements of sheep (case study : Pastures of northern Golestan province).

In areas where water is a scarce commodity, a strategy to determine water requirement of sheep to supply the amount of water, especially in droughts, are needed. The purpose of this paper is to offering a model to determine water requirement of sheep in winter pastures. This study was conducted in four commercial ocks of sheep in winter pastures of north of Golestan province (Gomishan and Aq-Qala) during the grazing season at December 2010 to April 2011. Among factors affecting on water requirement of sheep, the factors of ambient temperature, rainfall, wind speed, relative humidity, forage moisture and level of activity of sheep has been studied. Stepwise regression analysis is used to determine the factors that have most influence on water consumption of sheep during the grazing. Variables of Ambient temperature (t = 12.532, p < 0.01), forage moisture (t = - 6.124, p < 0.01) and rainfall (t =4.011, p < 0.01), respectively, were selected in Stepwise regression analysis. A linear formula (r2= 0.87, p < 0.01) to determine the water requirement of sheep is obtained from this study.