Fatty Acid Profiles and Eicosanoid Biosynthesis in Transition Dairy Cows

Abstract

The onset of lactation imposes considerable changes in dietary requirements and metabolic functions. These adaptations occur during the transition period (TP) that begins 3 wks before through 3 wk after parturition. This period is associated with an elevated incidence of diseases that cause a significant reduction in the profitability of dairy herds. Energy requirements of the TP dairy cow are unable to be met by the diet and must rely on tissue reserves. Mobilization of fat from tissues releases non-esterified fatty acids (NEFA) into the blood stream which are used as energy; however, NEFA function is not limited to energy supply. These compounds can serve as substrates for the biosynthesis of inflammatory lipid mediators (LM). The two major enzymes for eicosanoid synthesis are cyclooxygenases (COX) and lipoxigenases (LOX). The increased activity of these enzymatic pathways could lead to an enhanced inflammatory response. Despite recent advances in TP dairy cow health, little is known about the relationship between variations in the plasma fatty acid (FA) profile and the production of LM through both COX and LOX biosynthetic pathways. We hypothesize that plasma FA profiles and expression of enzymes associated with eicosanoid biosynthesis shift during the transition period.