Relation between liver lipid content and plasma biochemical indicators in dairy cows

ABSTRACT

Background: The incidence of metabolic disorders in dairy cows has increased as a result of intensive production practicesand genetic selection for milk yield. Among such disorders, liver lipidosis is very frequently observed and has significantnegative effects on cow health and milk yield. Severe energy supply deficit causes high fat mobilization, resulting in rapidbody condition loss and liver lipid infiltration, which cannot always be detected by known blood biochemical indicators.The main objective of the study was to determine possible associations of blood biochemical parameters with liver lipidinfiltration severity in high-yield multiparous Holstein cows along prepartum and postpartum periods.Materials, Methods & Results: Fifty-four high-yield Holstein cows from a herd managed in a free-stall system in thenorthwest region of the state of Rio Grande do Sul, Brazil were evaluated. Cows were divided in two groups accordingto their physiological status. Group 1 included 19 prepartum cows, with an average milk yield of 44.7 L/d in the previouslactation, and 2.8 average parity, and Group 2 included 35 postpartum cows, with an average milk yield of 46.8 L/d in theprevious lactation, and 2.5 average parity. The farm produced 10,000 kg milk per year, containing 3.5% of fat, 3.2% ofprotein and 4.7% of lactose. Total cholesterol (CH), plasma triglycerides (TGp), beta-hydroxybutyrate (BHB), albumin(ALB), non-esterified free fatty acids (NEFA) levels, and aspartate aminotransferase (AST) and creatine kinase (CK) activities were analyzed in the plasma and liver triglycerides (TGl) levels were determined in liver tissue samples. The SPSSstatistical software was used for the statistical analyses. The obtained data were analyzed for normality by the Shapiro-Wilktest and for homoscedasticity by Bartlett test. Data were submitted to analysis of variance, and means were compared bythe...