{"references": ["AL-ABBASY, E.G.H.: Effect of Adding Two Levels of Niacin in Milk Production and Controlling Indicatorsof Ketosis in Friesian Cows Postpartum. Br. J. Dairy Sci., 3(1)1-4, 2013.", "CINCOVI\u0106, M.R., BELI\u0106, B., \u0110OKOVI\u0106 R., TOHOLJ B., HRISTOVSKA T., DELI\u0106 B., DO\u0160ENOVI\u0106 M.: Insulin resistance in cows during dry period and early lactation. Contemporary agriculture, 63(1-2)98-105, 2014.", "CINCOVI\u0106, M.R., BELI\u0106, B., RADOJI\u010cI\u0106, B., HRISTOV, S., \u0110OKOVI\u0106, R.: Influence of lipolysis and ketogenesis to metabolic and hematological parameters in dairy cows during periparturient period. Acta veterinaria (Beograd), 62(4)429-444, 2012.", "\u0110OKOVI\u0106 R. CINCOVI\u0106, M., KURCUBIC, V., PETROVI\u0106, M., LALOVI\u0106, M., JA\u0160OVI\u0106, B., STANIMIROVI\u0106, Z.: Endocrine and Metabolic Status of Dairy Cows during Transition Period. Thai J. Vet. Med., 44(1)59-66, 2014.", "KAMANNA, V.S., KASHYAP, M.L.: Mechanism of action of niacin. Am J Cardiol. Apr 17;101(8A):20B-26B, 2008.", "KARKOOD, K., TAMIZRAD, K.: Effect of niacin supplementation on performance and blood parameters of Holstein cows. South African Journal of Animal Science, 39:4, 2009.", "KUTAS. F. : Biochemistry of vitamins. Szent Istvan University Budapest, pp 50-55, 1994.", "MOREY, S.D., MAMEDOVA, L.K., ANDERSON, D.E., ARMENDARIZ, C.K., TITGEMEYER, E.C., BRADFORD, B.J.: Effects of encapsulated niacin on metabolism and production of periparturient dairy cows J. Dairy Sci., 94:5090-5104, 2011.", "NIEHOFF, I.D., HUTHER, L., LEBZIEN, P.: Niacin for cattle: A review. Br. J. Nutr., 101:5-19, 2009.", "NRC. National Research Council. Nutrient Requirements of DairyCattle. 7th rev. ed. Natl. Acad. Press, Washington, DC, 2001.", "PESCARA, J.B., PIRES, A.A., GRUMMER, R.R.: Antilipolytic and lipolytic effects of administering free or ruminally protected nicotinic acid to feed-restricted Holstein cows J. Dairy Sci,, 93:5385-5396, 2010.", "PIRES, J.A., PESCARA, J.B., GRUMMER, R.R.: Reduction of Plasma NEFA Concentration by Nicotinic Acid Enhances the Response to Insulin in Feed-Restricted Holstein Cows. J. Dairy Sci., 90:4635\u20134642, 2007a.", "PIRES, J.A., GRUMMER, R.R.: The Use of Nicotinic Acid to Induce Sustained Low Plasma Nonesterified Fatty Acids in Feed-Restricted Holstein Cows. J. Dairy Sci., 90:3725\u20133732, 2007b.", "YUAN, K., SHAVER, R.D.,BERTICS, S.J., ESPINEIRA, M., RUMMER, RR.: Effect of rumen-protected niacin on lipid metabolism, oxidative stress, and performance of transition dairy cows J Dairy Sci., 95:2673-2679, 2012."]}

The aim of our study was to examine the influence of niacin administration on lipid metabolism in cows during early lactation. Thirty Holstein-Friesian cows were included in experiment and were divided into two groups: cows suplemented with niacin (15) and negative controle nonsuplemented cows (15). Blood samples were taken by venepunction of v.coccigea in vacutainers for serum separation. Sampling was performed at calving and in first and second weeks of lactation. Concentration of blood NEFA, BHB, cholesterol and triglycerides was determined NEFA:cholesterol ratio was calculated as index of liver lipidosis. Cows that received niacin showed lower concentrations of NEFA and BHB and a higher concentration of triglycerides and cholesterol, also there is a significantly higher concentration of cholesterol per unit NEFA. Application of niacin in cows during periparturinet period showed positive effects on lipid metabolism such as decreased lipid mobilization (decreased NEFA), ketogenesis (decreased BHB) and liver lipidosis (higher triglycerides and cholesterol in blood and higher concentration of cholesterol per NEFA unit) in early lactation.