Prevalence of Ketosis and its Correlation with Lactation Stage, Parity and Peak of Milk Yield in Iran

Ketosis is a metabolic disorder which usually occurs in cows during1 early lactation in both, industrialized and developing countries. There are no data available about the prevalence of ketosis in major dairy producing provinces in Iran. This study investigated the prevalence of ketosis among 1,002 Iranian Holstein cows from days 5 to 50 post calving in various parity and lactation stages in 13 regions of Iran. Whole blood beta-Hydroxybutyrate (BHBA) concentration equal or more than 1,400 and 3,000 μmol L-1 were considered as subclinical ketosis (SCK) and clinical ketosis, respectively. The prevalence of SCK and clinical ketosis were 13.9 and 3.4%, respectively and higher prevalence of ketosis during second (42.2%) and third weeks (24.8%) post calving. The ketosis prevalence was found significant between regions, but not parity. Prevalence of ketosis was higher in Gorgan, Shahrekord and Sari than the other regions. The negative correlations between prevalence of ketosis (BHBA = 1400 μmol L-1) and blood glucose concentration and lactation stage were significant. In addition, the positive correlation between blood glucose concentration and lactation stage was also significant. Blood glucose and BHBA concentrations were not correlated with the parity stage. The mean milk production for cows suffering from clinical ketosis, SCK and healthy cows were 28, 35 and 45 kg day-1, respectively. Significant negative correlation coefficients were found between blood BHBA with peak milk yield. In conclusion, the present results show that the best times to identify clinical and SCK are 14 and 17 days after calving.