Hepatic lipidosis in high-yielding dairy cows during the transition period: hematochemical and histopathological findings

The aim of this study was to assess the severity and distribution of hepatic lipidosis in high-yielding dairy cows during the transition period by the evaluation of body condition score (BCS), serum levels of non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) and histological liver lipid content (GdL). Twenty-seven dairy cows, with a milk production of ~10 000 kg per year were enrolled in an experiment. Clinical examination was performed to evaluate the health status or the presence of periparturient diseases after calving. Animals were divided into two groups: healthy (HG; n = 11) and sick (SG; n = 16). The evaluation of BCS, NEFA, BHB and liver biopsies were performed at 15 ± 5 days prepartum (T0), 10 ± 2 days postpartum (T1), 30 ± 2 days postpartum (T2) and 50 ± 2 days postpartum (T3). Two-way repeated-measure ANOVA was applied to assess statistical significance of sampling time and between groups for all variables. Pearson’s correlation coefficient was used to investigate the relationship between all variables. Results showed BCS loss from T0 to T3 in SG and a significant increase of NEFA and BHB at T1. The GdL began to be mild at T0 increasing and becoming moderate to severe at T1, fairly regressing, but not disappearing, at T2 and T3, in both groups. This study showed that high lipomobilisation with a mild to moderate fat infiltration does not imply that ketosis or other periparturient diseases might be present. Our results suggest that hepatic lipidosis is associated with long-term histological and metabolic changes in dairy cows.