The objective of this research was to evaluate the association between ketonemia and serum paraoxonase-1 (PON1), malondialdehyde (MDA), and other blood components in tail and mammary veins of dairy cows. Forty-two Holstein dairy cows with decreased feed intake were divided into HIGH (?1.2mM ; n=31) and LOW (<1.2mM;n=11) groups based on the b-hydroxybutyrate concentration in plasma collected from the tail vein. The HIGH group had a significantly greater plasma non-esterified fatty acid (NEFA) concentration, but significantly lower serum PON1 activity and phospholipid concentration, and a tendency to have a lower cholesterol ester concentration than the LOW group. Serum PON1 activity was not correlated with the MDA concentration but was positively correlated with serum concentrations of cholesterol esters and phospholipids, and negatively correlated with the plasma NEFA concentration. These results suggest that serum PON1 activity is reduced by hyperketonemia and the relevance of PON1to MDA seems to not be direct, though it is involved.

Hanan Kamal has completed her PHD at the age of 33 years from Assiut University, Egypt. She is a member at the department of Animal Medicine, Faculty of Veterinary Medicine, Assiut, Egypt. She has over 35 publications that have been cited over 81 times, and her publication h-index is 5. She is a member of Japanese Society of Veterinary Science,  Egyptian Society for Cattle Disease, Egyptian Society for Equine Diseases and Egyptian society for Camel Diseases.