Lipid and lipoprotein profile changes in dairy cows in response to late pregnancy and the early postpartum period
Abstract. In dairy cows the peripartum period involves endocrine and metabolic changes to compensate for the increased energy requirement aggravated by reduced feed intake. Cows adjust to the resulting negative energy balance with the mobilization of lipids from adipose tissue that, if excessive, could lead to many transition disorders compromising the offspring's growth and well-being. The aim of this study was to evaluate the dynamic changes in serum lipid and lipoprotein profiles in five dairy cows during the peripartum period. For each cow body condition score (BCS) and body weight (BW) measurements as well as blood sampling was carried out 60, 30 and 15 days before calving (−60, −30 and −15 BC), at calving day (C) and on days 15, 30 and 60 after calving (+15, +30 and +60 AC). Blood samples were tested for serum total lipids, phospholipids, triglycerides, very low-density lipoproteins (VLDLs), total cholesterol (Total-Chol), high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs). One-way repeated measures analysis of variance (ANOVA) was applied to determine the effect of the peripartum period on the studied parameters in cows. A statistically significant effect of the peripartum period (P < 0.05) was found in the values of BCS, BW and all serum lipid and lipoprotein indices measured in cows. The changes observed in lipid indices of peripartum cows could be due to the start of milking and the increase in energy consumption in the body, confirming that metabolic adjustments occur as cows move from the gestation to the lactation period.