Evaluation of drinking water quality of dairy farms in summer and winter seasons in Isfahan Province

In order to evaluate of drinking water quality of dairy farms in Isfahan province، water samples were collected from 70 volunteer dairy farms in winter and summer of 2010. The Samples were sent to laboratory for determination of water quality parameters. Then، all data were analyzed by the GLM procedure of SAS software. Results were compared with standard values using one- sample T-Test. The farms categorized based on water quality by cluster procedure of SAS. Results were reported separately for each dairy farm. Results showed that there was not any significant difference between the two seasons in terms of chemical quality، with the exception of hardness، calcium، fluoride and potassium. Results indicated that chloride content in more than 80 percent of well water sample and 10 percent of tanker water sample were higher than standard value. TDS، EC، Ca and K in more than 50 percent of well sources were higher than the maximum limits (P< 0. 05). Hardness content in 75 percent of well source and more than 20 percent of tanker source were higher than the maximum limits and K content in more than 40 percent of well source and less than 10 percent of tanker source was higher than standard limits. It can be concluded that overall drinking water quality of many units tested for high-producing cows is unfavorable.