Survey on seasonal changes in somatic cell and microbial counts in dairy farms in Hamedan province

Microbial contamination and somatic cells are account as two important factors in reducing the shelf life and entire quality of raw and pasteurized milk. This study was carried out on the seasonal variation of milk microbial and somatic cell counts. Six industrial and traditional dairy farms from Hamedan province were sampled monthly for a period of one year. Records of somatic cell and bacterial count of samples were analyzed by using different statistical methods in SAS software. Least square mean (±SE) somatic cell count (cells per ml×1000) and total microbial was 325.10(±¬13.20) and 5287.03(±¬261.23), respectively. Differences in microbial count in industrial and traditional farms was significant (P<0.0001). Seasonal changes in total count was significant (P<0.0002) and the effect herd nested in farming system was significant (P<0.0001) as well. Also there were significant difference in farming system and herd on somatic cell counts (P<0.0001). Although industrial dairy farms had lower total count than traditional dairy farms, the somatic cell counts were higher and need to be more investigated on annually herd combination, dry-off time and cutting strategy of low producing and infertile dairy cows.