Document Type : Research Paper
Ph.D. Candidate, Univeristy College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Associate Professor, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Professor, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Feeding unsaturated fatty acids sources in dairy cows is a strategy to improve animal health during postpartum period. The aim of this study was to investigate the effects of different sources of fatty acids on dry matter intake (DMI), milk production and composition and blood metabolites during the transition period in Holstein dairy cow. Multiparous pregnant Holstein cows (n=35) were selected (around 21 days before calving) and assigned randomly to one of the five experimental treatments including: 1) control (Source of palmitic acid), 2) CLA supplementation, 3) extruded linseed (LIN), 4)extruded linseed and CLA blend (LIN+CLA), 5) meal and calcium oil sesame. DMI and milk yield were recorded daily. Blood samples were collected at -21, -14, -7, -3, 0, 3, 7, 14 and 21 d relative to calving to determine plasma concentration of glucose, cholesterol, triglyceride, low density lipoprotein (LDL) and nonesterified fatty acid (NEFA). DMI, milk yield and composition, plasma concentrations of NEFA and triglyceride were not affected by treatments. During the postpartum period, plasma concentrations of glucose were greater in CLA treatment compared with control, LIN and LIN+CLA diets. Control treatment had the greatest plasma concentration of LDL. Cholesterol concentration of control treatment was higher at 7 and 14 d post calving compared with other treatments. In overall, feeding the unsaturated fatty acid improved concentration of blood metabolites, although they had no effect on milk performance.