Cow milk fatty acids as predictive biomarkers for the diagnosis of hyperketonemia in early lactation

Negative energy balance (NEB) is an important phenomenon in the transition period of the lactation cycle in dairy cows, and measuring the current energy balance is useful in both applied and research settings [1]. NEB can lead to a variety of early lactation metabolic disorders, reduced fertility, and ultimately decreased milk production. One indicator of NEB related to adipose mobilization is the high plasma non-esterified fatty acid (NEFA) concentration. Since these NEFA are particularly rich in long-chain FA, elevated concentrations of these FA in milk fat were identified as valuable early warning biomarkers for subclinical ketosis [2]. Due to the limited availability of propionate, however, complete oxidation of NEFA is impaired, resulting in the production of ketone bodies (β-hydroxybutyrate, acetoacetate, and acetone), which might be referred to hyperketonemia [3]. The aim of this study was to deepen the knowledge regarding the possible association, during the early lactation, between the dairy cow milk FA concentration and the elevated plasmatic value of β-hydroxybutyrate and NEFA. Blood and milk samples of fiftyfour Holstein-Friesian dairy cows, in the first part of the lactation, were collected. Four lipid fractions (cholesterol esters, phospholipids, free FA and triacylglycerols) were isolated and analyzed. The FA composition was carried out by gas chromatography technique coupled with flame ionization detector. These profiles were used to investigate the diagnostic potential value of milk FA for the correct classification of cows with BHB and NEFA concentrations above the established thresholds (BHB<1,0 mmol/L and NEFA<0,5 mEq/L). The research has allowed to identify the major milk FA of each fraction with predictive rule in the possible development of hyperketonemia. Further studies in the clinical and therapeutic approach will be necessary to evaluate if these predictive FA change in relation on the administration of particular diets, supplements, and drugs that might prevent the development of hyperketonemia. References [1] Dórea, J. R. R.; French, E. A.; Armentano, L. E. J. Dairy Sci. 2016, 100, 6164-6176 [2] Duffield, T. F. Vet. Clin. North Am. Food Anim. Pract. 2009, 16, 231-253 [3] Jorjong, S.; van Knegsel, S.; Verwaeren, A. T. M. et al. J. Dairy Sci. 2015, 98, 5211-5221